Context: A 59-year-old woman is brought to the emergency room after collapsing at home. She had been sitting on her couch reading, when she started feeling lightheaded and lost consciousness. According to her husband, she was unconscious for approximately 30 seconds. Since regaining consciousness, she has continued to be lightheaded and dizzy. She has not had palpitations. Her only medication is simvastatin for hyperlipidemia. Her pulse is 37/min, respirations are 18/min, and blood pressure is 92/50 mm Hg. Her ECG is shown. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Administration of atropine


Context: A 78-year-old man presents to the hospital because of shortness of breath and chest pain that started a few hours ago. 3 weeks ago he had surgery for a total hip replacement with a prosthesis. The patient was treated with prophylactic doses of low-weight heparin until he was discharged. He did not have a fever, expectoration, or any accompanying symptoms. He has a history of right leg deep vein thrombosis that occurred 5 years ago. His vital signs include: heart rate 110/min, respiratory rate 22/min, and blood pressure 150/90 mm Hg. There were no significant findings on the physical exam. Chest radiography was within normal limits. What is the most likely diagnosis?

Question: What is the most likely diagnosis?

Answer: Pulmonary thromboembolism


Context: A 41-year-old woman with a past medical history significant for asthma and seasonal allergies presents with a new rash. She has no significant past surgical, social, or family history. The patient's blood pressure is 131/90 mm Hg, the pulse is 77/min, the respiratory rate is 17/min, and the temperature is 36.9°C (98.5°F). Physical examination reveals a sharply demarcated area of skin dryness and erythema encircling her left wrist. Review of systems is otherwise negative. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer: Contact dermatitis


Context: A 3-year-old male is brought to the pediatrician for a check-up. The patient has a history of recurrent ear infections and several episodes of pneumonia. His mother reports the presence of scaly skin lesions on the face and in the antecubital and popliteal fossa since the patient was 2 months old. Physical examination also reveals bruising of the lower extremities and petechiae distributed evenly over the boy's entire body. A complete blood count reveals normal values except for a decreased platelet count of 45,000/mL. Which of the following findings would be expected on follow-up laboratory work-up of this patient's condition?

Question: Which of the following findings would be expected on follow-up laboratory work-up of this patient's condition?

Answer: Decreased CD43 expression on flow cytometry


Context: A 62-year-old woman makes an appointment with her primary care physician because she recently started experiencing post-menopausal bleeding. She states that she suffered from anorexia as a young adult and has been thin throughout her life. She says that this nutritional deficit is likely what caused her to not experience menarche until age 15. She used oral contraceptive pills for many years, has never been pregnant, and experienced menopause at age 50. A biopsy of tissue inside the uterus reveals foci of both benign and malignant squamous cells. Which of the following was a risk factor for the development of the most likely cause of her symptoms?

Question: Which of the following was a risk factor for the development of the most likely cause of her symptoms?

Answer: Never becoming pregnant


Context: A 48-year-old woman is brought to the emergency department because of a 1-hour history of sudden-onset headache associated with nausea and vomiting. The patient reports she was sitting at her desk when the headache began. The headache is global and radiates to her neck. She has hypertension. She has smoked one pack of cigarettes daily for the last 10 years. She drinks alcohol occasionally. Her father had a stroke at the age 58 years. Current medications include hydrochlorothiazide. She is in severe distress. She is alert and oriented to person, place, and time. Her temperature is 38.2°C (100.8°F), pulse is 89/min, respirations are 19/min, and blood pressure is 150/90 mm Hg. Cardiopulmonary examination shows no abnormalities. Cranial nerves II–XII are intact. She has no focal motor or sensory deficits. She flexes her hips and knees when her neck is flexed while lying in a supine position. A CT scan of the head is shown. Which of the following is the most appropriate intervention?

Question: Which of the following is the most appropriate intervention?

Answer: Perform surgical clipping


Context: A 29-year-old nulligravid woman comes to the physician because of a 10-day history of small quantities of intermittent, blood-tinged discharge from her left nipple. There is no personal or family history of serious illness. She has smoked 1 pack of cigarettes daily for 5 years. Her last menstrual period was 12 days ago. She is sexually active and uses condoms inconsistently. Physical examination shows scant serosanguinous fluid expressible from the left nipple. There is no palpable breast mass or axillary lymphadenopathy. Examination shows no other abnormalities. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Subareolar ultrasound


Context: An investigator is studying the immune response and the spleen in a mouse model infected with Escherichia coli. Which of the following anatomical sites in the spleen is important for the initial maturation of B cells that will ultimately target Escherichia coli?

Question: Which of the following anatomical sites in the spleen is important for the initial maturation of B cells that will ultimately target Escherichia coli?

Answer: Germinal center


Context: A 28-year-old woman at 30 weeks gestation is rushed to the emergency room with the sudden onset of vaginal bleeding accompanied by intense abdominopelvic pain and uterine contractions. The intensity and frequency of pain have increased in the past 2 hours. This is her 1st pregnancy and she was diagnosed with gestational diabetes several weeks ago. Her vital signs include a blood pressure of 124/68 mm Hg, a pulse of 77/min, a respiratory rate of 22/min, and a temperature of 37.0°C (98.6°F). The abdominal examination is positive for a firm and tender uterus. An immediate cardiotocographic evaluation reveals a fetal heart rate of 150/min with prolonged and repetitive decelerations and high-frequency and low-amplitude uterine contractions. Your attending physician warns you about delaying the vaginal physical examination until a quick sonographic evaluation is completed. Which of the following is the most likely diagnosis in this patient?

Question: Which of the following is the most likely diagnosis in this patient?

Answer: Placenta abruption


Context: An 18-month-old girl is brought to the emergency room by her mother because of wheezing for 1 day. The baby has never had similar symptoms. She also has a runny nose and a cough. She is not feeding well. Her immunizations are up-to-date. Her rectal temperature is 38.8°C (101.8°F), the heart rate is 120/min, and the respiratory rate is 23/min. On examination, a clear nasal discharge is noticed with intercostal retractions. Chest auscultation reveals bilateral fine rales and diffuse fine wheezing. A chest X-ray is given in the exhibit. What is the most likely diagnosis?

Question: What is the most likely diagnosis?

Answer: Bronchiolitis


Context: A 61-year-old man presents to the urgent care clinic complaining of cough and unintentional weight loss over the past 3 months. He works as a computer engineer, and he informs you that he has been having to meet several deadlines recently and has been under significant stress. His medical history is significant for gout, hypertension, hypercholesterolemia, diabetes mellitus type 2, and pulmonary histoplasmosis 10 years ago. He currently smokes 2 packs of cigarettes/day, drinks a 6-pack of beer/day, and he endorses a past history of cocaine use back in the early 2000s but currently denies any drug use. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 87/min, and respiratory rate 18/min. His physical examination shows minimal bibasilar rales, but otherwise clear lungs on auscultation, grade 2/6 holosystolic murmur, and a benign abdominal physical examination. However, on routine lab testing, you notice that his sodium is 127 mEq/L. His chest X-ray is shown in the picture. Which of the following is the most likely underlying diagnosis?

Question: Which of the following is the most likely underlying diagnosis?

Answer: Small cell lung cancer


Context: A 22-year-old female presents to an urgent care clinic for evaluation of a loose bowel movement that she developed after returning from her honeymoon in Mexico last week. She states that she has been having watery stools for the past 3 days at least 3 times per day. She now has abdominal cramps as well. She has no significant past medical history, and the only medication she takes is depot-medroxyprogesterone acetate. Her blood pressure is 104/72 mm Hg; heart rate is 104/min; respiration rate is 14/min, and temperature is 39.4°C (103.0°F). Her physical examination is normal aside from mild diffuse abdominal tenderness and dry mucous membranes. Stool examination reveals no ova. Fecal leukocytes are not present. A stool culture is pending. In addition to oral rehydration, which of the following is the best treatment option for this patient?

Question: In addition to oral rehydration, which of the following is the best treatment option for this patient?

Answer: Ciprofloxacin


Context: A 12-year-old girl is brought to a pediatrician by her parents to establish care after moving to a new state. She does not have any complaints. Her past medical history is insignificant, and immunization history is up to date. The physical examination reveals a slightly raised strawberry-colored nodule on the skin of her abdomen below the umbilicus, as seen in the image. She adds that the nodule has been present ever since she can remember and has not changed in color or size. Which of the following neoplasms is associated with this patient's skin lesion?

Question: Which of the following neoplasms is associated with this patient's skin lesion?

Answer: Hemangioma


Context: A 65-year-old man comes to the physician because of progressive abdominal distension and swelling of his legs for 4 months. He has a history of ulcerative colitis. Physical examination shows jaundice. Abdominal examination shows shifting dullness and dilated veins in the periumbilical region. This patient's abdominal findings are most likely caused by increased blood flow in which of the following vessels?

Question: This patient's abdominal findings are most likely caused by increased blood flow in which of the following vessels?

Answer: Superior epigastric vein


Context: A 24-year-old man comes to the physician for the evaluation of a severely pruritic skin rash. Physical examination shows a symmetrical rash over the knees and elbows with tense, grouped vesicles, and several excoriation marks. Microabscesses in the papillary dermis are seen on light microscopy. Immunofluorescence shows deposits of immunoglobulin A at the tips of dermal papillae. This patient's skin findings are most likely associated with which of the following?

Question: This patient's skin findings are most likely associated with which of the following?

Answer: Gliadin-dependent hypersensitivity


Context: A 33-year-old man presents to the emergency department with agitation and combativeness. The paramedics who brought him in say that he was demonstrating violent, reckless behavior and was running into oncoming traffic. Chemical sedation is required to evaluate the patient. Physical examination reveals horizontal and vertical nystagmus, tachycardia, and profuse diaphoresis. Which of the following is the most likely causative agent in this patient?

Question: Which of the following is the most likely causative agent in this patient?

Answer: Phencyclidine (PCP)


Context: One day after undergoing a left carotid endarterectomy, a 63-year-old man has a severe headache. He describes it as 9 out of 10 in intensity. He has nausea. He had 80% stenosis in the left carotid artery and received heparin prior to the surgery. He has a history of 2 transient ischemic attacks, 2 and 4 months ago. He has hypertension, type 2 diabetes mellitus, and hypercholesterolemia. He has smoked one pack of cigarettes daily for 40 years. He drinks 1–2 beers on weekends. Current medications include lisinopril, metformin, sitagliptin, and aspirin. His temperature is 37.3°C (99.1°F), pulse is 111/min, and blood pressure is 180/110 mm Hg. He is confused and oriented only to person. Examination shows pupils that react sluggishly to light. There is a right facial droop. Muscle strength is decreased in the right upper and lower extremities. Deep tendon reflexes are 3+ on the right. There is a left cervical surgical incision that shows no erythema or discharge. Cardiac examination shows no abnormalities. A complete blood count and serum concentrations of creatinine, electrolytes, and glucose are within the reference range. A CT scan of the head is shown. Which of the following is the strongest predisposing factor for this patient's condition?

Question: Which of the following is the strongest predisposing factor for this patient's condition?

Answer: Hypertension


Context: A 25-year-old mother presents to her primary care physician for wrist pain. The patient recently gave birth to a healthy newborn at 40 weeks gestation. Beginning one week ago, she started having pain over her wrist that has steadily worsened. The patient notes that she also recently fell while walking and broke the fall with her outstretched arm. The patient is an accountant who works from home and spends roughly eight hours a day typing or preparing financial statements. Recreationally, the patient is a competitive cyclist who began a rigorous training routine since the birth of her child. The patient's past medical history is notable for hypothyroidism that is treated with levothyroxine. On physical exam, inspection of the wrist reveals no visible or palpable abnormalities. Pain is reproduced when the thumb is held in flexion, and the wrist is deviated toward the ulna. The rest of the patient's physical exam is within normal limits. Which of the following is the best next step in management?

Question: Which of the following is the best next step in management?

Answer: Rest and ibuprofen


Context: A 55-year-old woman comes to the physician because of a 2-week history of painful swelling on the right side of her face. The pain worsens when she eats. Examination of the face shows a right-sided, firm swelling that is tender to palpation. Oral examination shows no abnormalities. Ultrasonography shows a stone located in a duct that runs anterior to the masseter muscle and passes through the buccinator muscle. Sialoendoscopy is performed to remove the stone. At which of the following sites is the endoscope most likely to be inserted during the procedure?

Question: At which of the following sites is the endoscope most likely to be inserted during the procedure?

Answer: Lateral to the second upper molar tooth


Context: Ten days after the vaginal delivery of a healthy infant girl, a 27-year-old woman is brought to the physician by her husband because of frequent mood changes. She has been tearful and anxious since she went home from the hospital 2 days after delivery. She says that she feels overwhelmed with her new responsibilities and has difficulties taking care of her newborn because she feels constantly tired. She only sleeps for 2 to 3 hours nightly because the baby “is keeping her awake.” Sometimes, the patient checks on her daughter because she thinks she heard her cry but finds her sleeping quietly. Her husband says that she is afraid that something could happen to the baby. She often gets angry at him and has yelled at him when he picks up the baby without using a hand sanitizer beforehand. She breastfeeds the baby without any problems. The patient's mother has bipolar disorder with psychotic features. The patient's vital signs are within normal limits. Physical examination shows an involuting uterus consistent in size with her postpartum date. Mental status examination shows a labile affect with no evidence of homicidal or suicidal ideation. Laboratory studies show a hemoglobin concentration of 13 g/dL and a thyroid-stimulating hormone level of 3.1 μU/mL. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Reassurance


Context: A previously healthy 82-year-old man dies in a motor vehicle collision. At autopsy, the heart shows slight ventricular thickening. There are abnormal, insoluble aggregations of protein filaments in beta-pleated linear sheets in the ventricular walls and, to a lesser degree, in the atria and lungs. No other organs show this abnormality. Bone marrow examination shows no plasma cell dyscrasia. The abnormal protein aggregations are most likely composed of which of the following?

Question: The abnormal protein aggregations are most likely composed of which of the following?

Answer: Normal transthyretin


Context: A 2-year-old boy is brought to the physician with complaints of gingival growth in the lower jaw with associated pain for the past few weeks. He has no history of trauma or any other significant medical conditions. His temperature is 37.0°C (98.6°F), pulse is 92/min, and respiratory rate is 24/min. On extraoral examination, a swelling of 4 cm x 2 cm is present on the left lower jaw. On intraoral examination, a diffuse erythematous swelling covered with necrotic slough is present on the gingiva. Computed tomography (CT) scan of the head shows multiple soft tissue density lesions involving mandibular, maxillary, left occipital, and temporal regions. Which of the following findings, if present, would be the most specific indicator of the disease in this patient?

Question: Which of the following findings, if present, would be the most specific indicator of the disease in this patient?

Answer: Birbeck granules


Context: A 62-year-old man presents to the emergency department with chest pain. He was at home watching television when he suddenly felt chest pain that traveled to his back. The patient has a past medical history of alcoholism, obesity, hypertension, diabetes, and depression. His temperature is 98.4°F (36.9°C), blood pressure is 177/118 mmHg, pulse is 123/min, respirations are 14/min, and oxygen saturation is 97% on room air. Physical exam reveals a S4 on cardiac exam and chest pain that seems to worsen with palpation. The patient smells of alcohol. The patient is started on 100% oxygen and morphine. Which of the following is the best next step in management?

Question: Which of the following is the best next step in management?

Answer: Labetalol


Context: A 28-year-old G1P0 woman comes to the emergency department complaining that her water just broke. She reports irregular prenatal care due to her erratic schedule. She is also unsure of her gestational age but claims that her belly began to show shortly after she received her thyroidectomy for her Graves disease about 9 months ago. She denies any known fevers, chills, abnormal vaginal discharge/bleeding, or sexually transmitted infections. She develops frequent and regular contractions and subsequently goes into active labor. A fetus was later vaginally delivered with a fetal heart rate of 180 bpm. A neonatal physical examination demonstrates a lack of a sagittal cranial suture and an APGAR score of 8 and 8, at 1 and 5 minutes respectively. What findings would you expect in the baby?

Question: What findings would you expect in the baby?

Answer: High levels of free T4 and total T3


Context: A 40-year-old male visits a urologist and reports that for the past 2 weeks, his penis has been gradually curving to the right with associated pain during intercourse. He is able to have a normal erection and he does not recollect of any trauma to his penis. Although he is married, he admits to having unprotected sexual relationship with several females in the past year. His vitals are normal and physical examination in unremarkable except for a lesionless curved penis. It is painless to touch. Test results for sexually transmitted disease is pending. Which of the following is the most likely cause?

Question: Which of the following is the most likely cause?

Answer: Fibrosis of tunica albuginea


Context: An 18-day-old newborn has difficulty feeding and diarrhea for 2 days. During this period he has vomited after each of his feeds. He was born at 28 weeks' gestation and weighed 1100-g (2-lb 7-oz). His feeds consist of breast milk and cow milk based-formula. He appears lethargic. His temperature is 36.4°C (97.5°F), pulse is 120/min, respirations are 67/min and blood pressure is 70/35 mm Hg. Examination shows diffuse abdominal tenderness; rigidity and guarding are present. Bowel sounds are absent. Test of the stool for occult blood is positive. His hemoglobin concentration is 12.8 g/dL, leukocyte count is 18,000/mm3 and platelet count is 78,000/mm3. An x-ray of the abdomen is shown. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer:
Necrotizing enterocolitis
"


Context: A 6-month-old male infant is brought to a pediatrician by his guardian for scheduled immunizations. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. He is up to date on all vaccines and is meeting all developmental milestones. The infant is generally healthy; however, the guardian is concerned about multiple patches of bluish discolorations on the skin overlying the lower back and sacrum. A review of medical records indicates that these patches have been present since birth. On further review the child was placed into protective services due to neglect and abuse by his biological family. On physical examination, his vital signs are normal. The pediatrician notes the presence of multiple blue-brown patches over the lumbosacral region, buttocks, and back. These patches are soft and nontender on palpation. Which of the following is the best next step in management of the infant?

Question: Which of the following is the best next step in management of the infant?

Answer: Reassurance


Context: A previously healthy 46-year-old woman comes to the physician with a one-week history of productive cough and fatigue. Two weeks ago, she had fever, nasal congestion, rhinorrhea, and myalgias that resolved with supportive care. She has not traveled out of the United States. Pulmonary examination shows dullness to percussion and increased fremitus at the right middle lobe. An x-ray of the chest is shown. A sputum sample is most likely to show which of the following findings?

Question: A sputum sample is most likely to show which of the following findings?

Answer: Gram-positive, catalase-positive cocci


Context: A 34-year-old man comes to the physician because of progressive swelling of the left lower leg for 4 months. One year ago, he had an episode of intermittent fever and tender lymphadenopathy that occurred shortly after he returned from a trip to India and resolved spontaneously. Physical examination shows 4+ nonpitting edema of the left lower leg. His leukocyte count is 8,000/mm3 with 25% eosinophils. A blood smear obtained at night confirms the diagnosis. Treatment with diethylcarbamazine is initiated. Which of the following is the most likely route of transmission of the causal pathogen?

Question: Which of the following is the most likely route of transmission of the causal pathogen?

Answer: Deposition of thread-like larvae into the skin by a female mosquito


Context:
A 23-year-old woman presents with progressively worsening headache, photophobia, and intermittent fever that have lasted for 6 days. She says her headache is mostly frontal and radiates down her neck. She denies any recent history of blood transfusions, recent travel, or contact with animals. Her past medical history is unremarkable. She is sexually active with a single partner for the past 3 years. Her temperature is 38.5°C (101.3°F). On physical examination, she appears pale and diaphoretic. A fine erythematous rash is noted on the neck and forearms. A lumbar puncture is performed and CSF analysis reveals:
Opening pressure: 300 mm H2O
  Erythrocytes: None
Leukocytes: 72/mm3
Neutrophils: 10%
Lymphocytes: 75%
Mononuclear: 15%
Protein: 100 mg/dL
Glucose: 70 mg/dL
Which of the following is the most likely diagnosis in this patient?

Question:
A lumbar puncture is performed and CSF analysis reveals:
Opening pressure: 300 mm H2O
  Erythrocytes: None
Leukocytes: 72/mm3
Neutrophils: 10%
Lymphocytes: 75%
Mononuclear: 15%
Protein: 100 mg/dL
Glucose: 70 mg/dL
Which of the following is the most likely diagnosis in this patient?

Answer: Enterovirus meningitis


Context: A 26-year-old man comes to the emergency room complaining of severe, episodic back pain. He states that it started suddenly this morning. The pain is 9/10 and radiates to his left groin. He endorses seeing blood in his urine earlier but denies dysuria or abnormal urethral discharge. His medical history is significant for Crohn disease, gout, and insulin-dependent diabetes. He takes insulin, allopurinol, and sulfasalazine. He is sexually active with multiple women and uses condoms inconsistently. He drinks 4 cans of beer on the weekends. He denies tobacco use or other recreational drug use. The patient’s temperature is 99°F (37.2°C), blood pressure is 121/73 mmHg, pulse is 89/min, and respirations are 14/min with an oxygen saturation of 94% on room air. A contrast computed tomography of the abdomen and pelvis reveals a 5-mm stone in the left ureter without evidence of hydronephrosis. Urinalysis and urine microscopy reveal hematuria and envelope-shaped crystals. Which of the following most likely contributed to the development of the patient’s acute symptoms?

Question: Which of the following most likely contributed to the development of the patient’s acute symptoms?

Answer: Crohn disease


Context: A 19-year-old man with a history of type 1 diabetes presents to the emergency department for the evaluation of a blood glucose level of 492 mg/dL. Laboratory examination revealed a serum bicarbonate level of 13 mEq/L, serum sodium level of 122 mEq/L, and ketonuria. Arterial blood gas demonstrated a pH of 6.9. He is admitted to the hospital and given bicarbonate and then started on an insulin drip and intravenous fluid. Seven hours later when his nurse is making rounds, he is confused and complaining of a severe headache. Repeat sodium levels are unchanged, although his glucose level has improved. His vital signs include a temperature of 36.6°C (98.0°F), pulse 50/min, respiratory rate 13/min and irregular, and blood pressure 177/95 mm Hg. What other examination findings would be expected in this patient?

Question: What other examination findings would be expected in this patient?

Answer: Papilledema


Context: A 24-year-old African American college student comes to the office for a scheduled visit. He has been healthy, although he reports occasional flank discomfort which comes and goes. He denies any fever, chills, dysuria, or polyuria in the past year. His vaccinations are up to date. His family history is unknown, as he was adopted. He smokes 1 pack of cigarettes every 3 days, drinks socially, and denies any current illicit drug use, although he endorses a history of injection drug use. He currently works as a waiter to afford his college tuition. His physical examination shows a young man with a lean build, normal heart sounds, clear breath sounds, bowel sounds within normal limits, and no lower extremity edema. You order a urinalysis which shows 8 red blood cells (RBCs) per high-power field (HPF). The test is repeated several weeks later and shows 6 RBCs/HPF. What is the most appropriate next step in management?

Question: What is the most appropriate next step in management?

Answer: Intravenous (IV) pyelogram


Context:
An 11-year-old girl is brought to the emergency department after she fell during a dance class. She was unable to stand after the accident and has a painful and swollen knee. On presentation she says that she has had 2 previous swollen joints as well as profuse bleeding after minor cuts. Based on her presentation, a panel of bleeding tests is obtained with the following results:

Bleeding time: 11 minutes
Prothrombin time: 12 seconds
Partial thromboplastin time: 52 seconds

Which of the following treatments would be most effective in treating this patient's condition?

Question:
Based on her presentation, a panel of bleeding tests is obtained with the following results:

Bleeding time: 11 minutes
Prothrombin time: 12 seconds
Partial thromboplastin time: 52 seconds

Which of the following treatments would be most effective in treating this patient's condition?

Answer: Desmopressin


Context: Researchers are studying the effects of a new medication for the treatment of type 2 diabetes. A randomized group of 100 subjects is given the new medication 1st for 2 months, followed by a washout period of 2 weeks, and then administration of the gold standard medication for 2 months. Another randomized group of 100 subjects is be given the gold standard medication 1st for 2 months, followed by a washout period of 2 weeks, and then administration of the new medication for 2 months. What is the main disadvantage of this study design?

Question: What is the main disadvantage of this study design?

Answer: Carryover effect


Context: A 33-year-old woman, gravida 1, para 0, at 26 weeks' gestation comes to the physician for a routine prenatal examination. Her pregnancy has been uneventful. Physical examination shows a uterus consistent in size with a 26-week gestation. She is given an oral 50-g glucose load; 1 hour later, her serum glucose concentration is 116 mg/dL. Which of the following most likely occurred immediately after the entrance of glucose into the patient's pancreatic beta-cells?

Question: Which of the following most likely occurred immediately after the entrance of glucose into the patient's pancreatic beta-cells?

Answer: Generation of adenosine triphosphate


Context: You are treating a neonate with meningitis using ampicillin and a second antibiotic, X, that is known to cause ototoxicity. What is the mechanism of antibiotic X?

Question: What is the mechanism of antibiotic X?

Answer: It binds the 30s ribosomal subunit and inhibits formation of the initiation complex


Context: A 52-year-old man is brought to the emergency department after being found down on the sidewalk. On presentation, he is found to have overdosed on opioids so he is given naloxone and quickly recovers. Physical exam also reveals lumps on his neck and face that are covered by small yellow granules. These lumps are slowly draining yellow pus-like fluid. He says that these lumps have been present for several months, but he has ignored them because he has not had any fever or pain from the lumps. He does not recall the last time he visited a primary care physician or a dentist. Oral exam reveals multiple cavities and abscesses. The most likely cause of this patient's facial lumps has which of the following characteristics?

Question: The most likely cause of this patient's facial lumps has which of the following characteristics?

Answer: Gram-positive rod


Context: A 34-year-old woman presents to the physician because of fever and sore throat for 2 days. She also reports generalized body pain and fatigue over this period. She was diagnosed with Graves’ disease 6 months ago. Because of arthralgias and rash due to methimazole 3 months ago, her physician switched methimazole to PTU. She appears ill. The vital signs include: temperature 38.4℃ (101.1℉), pulse 88/min, respiratory rate 12/min, and blood pressure 120/80 mm Hg. A 1 × 1 cm ulcer is seen on the side of the tongue and is painful with surrounding erythema. Examination of the neck, lungs, heart, and abdomen shows no abnormalities. She had normal liver aminotransferases last week. Which of the following is the most important diagnostic study at this time?

Question: Which of the following is the most important diagnostic study at this time?

Answer: Complete blood count with differential


Context: A 45-year-old man with a history of poorly controlled human immunodeficiency virus (HIV) infection presents to the emergency room complaining of clumsiness and weakness. He reports a 3-month history of worsening balance, asymmetric muscle weakness, and speech difficulties. He recently returned from a trip to Guatemala to visit his family. He has been poorly compliant with his anti-retroviral therapy and his most recent CD4 count was 195. His history is also notable for rheumatoid arthritis and hepatitis C. His temperature is 99°F (37.2°C), blood pressure is 140/90 mmHg, pulse is 95/min, and respirations are 18/min. On exam, he has 4/5 strength in his right upper extremity, 5/5 strength in his left upper extremity, 5/5 strength in his right lower extremity, and 3/5 strength in his left lower extremity. His speech is disjointed with intermittent long pauses between words. Vision is 20/100 in the left eye and 20/40 in his right eye; previously, his eyesight was 20/30 bilaterally. This patient most likely has a condition caused by which of the following types of pathogens?

Question: This patient most likely has a condition caused by which of the following types of pathogens?

Answer: Polyomavirus


Context: A 6-year-old girl is brought to the pediatrician by her father for an annual physical examination. The father reports that the patient is a happy and healthy child, but he sometimes worries about her weight. He says that she is a “picky” eater and only wants chicken nuggets and French fries. He also notes some mild acne on her cheeks and forehead but thinks it’s because she “doesn’t like baths.” The father says she has met all her pediatric milestones. She has recently started kindergarten, can tell time, and is beginning to read. Her teacher says she gets along with her classmates well. The patient was born at 38 weeks gestation. She has no chronic medical conditions and takes only a multivitamin. Height and weight are above the 95th percentile. Physical examination reveals scattered comedones on the patient’s forehead and bilateral cheeks. There is palpable breast tissue bilaterally with raised and enlarged areolae. Scant axillary hair and coarse pubic hair are also noted. A radiograph of the left hand shows a bone age of 9 years. Serum follicular stimulating hormone (FSH) level is 9.6 mU/mL (normal range 0.7-5.3 mU/mL) and luteinizing hormone (LH) level is 6.4 mU/mL (normal range < 0.26 mU/mL). Which of the following is the most appropriate diagnostic test?

Question: Which of the following is the most appropriate diagnostic test?

Answer: Head computed tomography (CT)


Context: A 42-year-old woman presents complaining of pain in her hands. She reports that the pain is in both hands, and that it is usually worse in the morning. She reports that her hands are also stiff in the morning, but that this gradually improves throughout the morning. She notes, however, that her symptoms seem to be getting worse over the last three months. What is the most likely pathogenesis of her disease process?

Question: What is the most likely pathogenesis of her disease process?

Answer: Production of antibodies against antibodies


Context: A 67-year-old male presents to the emergency department with sudden onset shortness of breath and epigastric pain. The patient has a past medical history of GERD, obesity, diabetes mellitus type II, anxiety, glaucoma, and irritable bowel syndrome. His current medications include omeprazole, insulin, metformin, lisinopril, and clonazepam as needed. The patient's temperature is 99.5°F (37.5°C), pulse is 112/min, blood pressure is 90/70 mmHg, respirations are 18/min, and oxygen saturation is 95% on room air. On physical exam the patient's lungs are clear to auscultation bilaterally. JVD is notable and cardiac auscultation is not revealing. An EKG is obtained in the emergency department. The patient is given a bolus of fluids and his pulse becomes 80/min with a blood pressure of 105/75 mmHg. The patient is then started on beta-blockers, oxygen, nitroglycerin, morphine, IV fluids, and aspirin. Repeat vitals demonstrate a blood pressure of 80/65 mmHg. Which of the following is the best explanation of this patient's current vital signs?

Question: Which of the following is the best explanation of this patient's current vital signs?

Answer: Increased cGMP


Context: A 70-year-old man comes to the physician because of a painless skin lesion on his neck for the past 5 months. The lesion has gradually become darker in color and is often pruritic. He has a similar lesion on the back. He is a retired landscaper. He has smoked half a pack of cigarettes daily for 45 years. Physical examination shows a 0.9-cm hyperpigmented papule on the neck with a greasy, wax-like, and stuck-on appearance. Histopathologic examination is most likely to show which of the following?

Question: Histopathologic examination is most likely to show which of the following?

Answer: Immature keratinocytes with small keratin-filled cysts


Context: A 23-year-old man presents to the emergency department brought in by police. He was found shouting at strangers in the middle of the street. The patient has no significant past medical history, and his only medications include a short course of prednisone recently prescribed for poison ivy exposure. His temperature is 77°F (25°C), blood pressure is 90/50 mmHg, pulse is 90/min, respirations are 17/min, and oxygen saturation is 98% on room air. The patient is only wearing underwear, and he is occasionally mumbling angrily about the government. He appears to be responding to internal stimuli, and it is difficult to obtain a history from him. Which of the following is the next best step in management?

Question: Which of the following is the next best step in management?

Answer: Warmed IV normal saline and warm blankets


Context: A 66-year-old man with coronary artery disease and hypertension comes to the emergency department because of intermittent retrosternal chest pain, lightheadedness, and palpitations. He has smoked one pack of cigarettes daily for 39 years. His pulse is 140/min and irregularly irregular, respirations are 20/min, and blood pressure is 108/60 mm Hg. An ECG shows an irregular, narrow-complex tachycardia with absent P waves. A drug with which of the following mechanisms of action is most likely to be effective in the long-term prevention of embolic stroke in this patient?

Question: A drug with which of the following mechanisms of action is most likely to be effective in the long-term prevention of embolic stroke in this patient?

Answer: Interference with carboxylation of glutamate residues


Context: A 65-year-old woman comes to the physician because of a 3-month history of intermittent palpitations and shortness of breath. Cardiopulmonary examination shows no other abnormalities. An ECG shows an absence of P waves, an oscillating baseline, and irregular RR intervals at a rate of approximately 95 beats per minute. The difference between atrial and ventricular rates in this patient is most likely due to which of the following?

Question: The difference between atrial and ventricular rates in this patient is most likely due to which of the following?

Answer: Temporary inactivation of Na+ channels in the AV node


Context: A 17-year-old woman presents to the emergency department with abdominal and pelvic pain. She states it started 3 days ago and it has been getting gradually worse. She states it is diffuse and is located over her abdomen, pelvis, and inside her vagina. She also endorses vaginal pruritus and a discharge from her vagina. The patient works in an ice cream parlor and is sexually active with multiple different partners. Her temperature is 98.0°F (36.7°C), blood pressure is 122/80 mmHg, pulse is 82/min, respirations are 15/min, and oxygen saturation is 98% on room air. Physical exam is notable for a foul smelling vagina with a thin, white discharge. Her abdomen is diffusely tender. The patient is noted to be itching her vagina during the exam. Which of the following is the most appropriate initial step in management?

Question: Which of the following is the most appropriate initial step in management?

Answer: Urine hCG


Context: A 52-year-old man presents to his primary care physician because he has been experiencing shortness of breath and cough. He began feeling short of breath when playing recreational soccer with his friends. Over time these episodes have become more severe. They now impair his ability to work as a construction worker. In addition, he has developed a chronic dry cough that has been increasing in intensity. Radiography reveals subpleural cystic enlargement, and biopsy reveals fibroblast proliferation in the affected tissues. Which of the following describes the mechanism of action for a drug that can cause a similar pattern of pulmonary function testing as would be seen in this disease?

Question: Which of the following describes the mechanism of action for a drug that can cause a similar pattern of pulmonary function testing as would be seen in this disease?

Answer: Dihydrofolate reductase inhibitor


Context: While walking through a park with his wife, a 51-year-old man with type 2 diabetes mellitus develops nausea, sweating, pallor, and palpitations. For the past 3 weeks, he has been trying to lose weight and has adjusted his diet and activity level. He eats a low-carb diet and swims 3 times a week. The man returned home from a training session 2 hours ago. Current medications include basal insulin and metformin. Shortly before his wife returns from their car with his emergency medication kit, he becomes unconscious. Administration of which of the following is the most appropriate next step in management?

Question: Administration of which of the following is the most appropriate next step in management?

Answer: Intramuscular glucagon


Context: An x-ray of the chest is conducted and shown below. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Administer isoniazid for 9 months


Context:
A 45-year-old woman presents to her physician with a four-month history of headache. Her headache is nonfocal but persistent throughout the day without any obvious trigger. She was told that it was a migraine but has never responded to sumatriptan, oxygen, or antiemetics. She takes amlodipine for hypertension. She does not smoke. She denies any recent weight loss or constitutional symptoms. Her temperature is 98°F (36.7°C), blood pressure is 180/100 mmHg, pulse is 70/min, and respirations are 15/min. She is obese with posterior cervical fat pads and central abdominal girth. Her neurological exam is unremarkable. In her initial laboratory workup, her fasting blood glucose level is 200 mg/dL. The following additional lab work is obtained and is as follows:

Serum:
Na+: 142 mEq/L
Cl-: 102 mEq/L
K+: 4.1 mEq/L
HCO3-: 24 mEq/L
BUN: 20 mg/dL
Glucose: 135 mg/dL
Creatinine: 1.3 mg/dL
Ca2+: 10.0 mg/dL
AST: 8 U/L
ALT: 8 U/L
24-hour urinary cortisol: 500 µg (reference range < 300 µg)
Serum cortisol: 25 µg/mL (reference range 5-23 µg/dL)
24-hour low dose dexamethasone suppression test: Not responsive
High dose dexamethasone suppression test: Responsive
Adrenocorticotropin-releasing hormone (ACTH): 20 pg/mL (5-15 pg/mL)

Imaging reveals a 0.5 cm calcified pulmonary nodule in the right middle lobe that has been present for 5 years but an otherwise unremarkable pituitary gland, mediastinum, and adrenal glands. What is the best next step in management?

Question: What is the best next step in management?

Answer: Inferior petrosal sinus sampling


Context: During the exam of a 2-day-old female neonate you determine that she appears lethargic, cyanotic, and has a coarse tremor of her right arm. The patient's mother explains that she observed what she believed to be seizure-like activity just before you arrived in the room. The mother has a history of type two diabetes mellitus and during childbirth there was a delay in cord clamping. You decide to get electrolytes and a complete blood count to work up this patient. The labs are significant for mild hypoglycemia and a hematocrit of 72%. What is the most effective treatment for this patient's condition?

Question: What is the most effective treatment for this patient's condition?

Answer: Partial exchange transfusion with hydration


Context:
A 75-year-old woman comes to the physician because of generalized weakness for 6 months. During this period, she has also had a 4-kg (8.8-lb) weight loss and frequent headaches. She has been avoiding eating solids because of severe jaw pain. She has hypertension and osteoporosis. She underwent a total left-sided knee arthroplasty 2 years ago because of osteoarthritis. The patient does not smoke or drink alcohol. Her current medications include enalapril, metoprolol, low-dose aspirin, and a multivitamin. She appears pale. Her temperature is 37.5°C (99.5°F), pulse is 82/min, and blood pressure is 135/80 mm Hg. Physical examination shows no abnormalities. Laboratory studies show:
Hemoglobin 10 g/dL
Mean corpuscular volume 87 μm3
Leukocyte count 8,500/mm3
Platelet count 450,000/mm3
Erythrocyte sedimentation rate 90 mm/h
Which of the following is the most appropriate next step in management?"

Question:
Laboratory studies show:
Hemoglobin 10 g/dL
Mean corpuscular volume 87 μm3
Leukocyte count 8,500/mm3
Platelet count 450,000/mm3
Erythrocyte sedimentation rate 90 mm/h
Which of the following is the most appropriate next step in management?"

Answer: Oral prednisone and temporal artery biopsy


Context: A 24-year-old primigravida at 28 weeks gestation presents to the office stating that she “can’t feel her baby kicking anymore.” She also noticed mild-to-moderate vaginal bleeding. A prenatal visit a few days ago confirmed the fetal cardiac activity by Doppler. The medical history is significant for GERD, hypertension, and SLE. The temperature is 36.78°C (98.2°F), the blood pressure is 125/80 mm Hg, the pulse is 70/min, and the respiratory rate is 14/min. Which of the following is the next best step in evaluation?

Question: Which of the following is the next best step in evaluation?

Answer: Confirmation of cardiac activity by Doppler


Context: A 47-year-old woman comes to her primary care doctor because of a new, pruritic rash. She was gardening in her yard two days ago and now has an eczematous papulovesicular rash on both ankles. You also note a single, 5 mm brown lesion with a slightly raised border on her left thigh. You prescribe a topical corticosteroid for contact dermatitis. Which of the following is the appropriate next step for the thigh lesion?

Question: Which of the following is the appropriate next step for the thigh lesion?

Answer: Further questioning


Context: A 28-year-old man presents to the emergency department with vomiting. He states that he has experienced severe vomiting starting last night that has not been improving. He states that his symptoms improve with hot showers. The patient has presented to the emergency department with a similar complaints several times in the past as well as for intravenous drug abuse. His temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 110/min, respirations are 22/min, and oxygen saturation is 98% on room air. Physical exam is deferred as the patient is actively vomiting. Which of the following is associated with the most likely diagnosis?

Question: Which of the following is associated with the most likely diagnosis?

Answer: Marijuana use


Context: A 12-year-old female presents to your office complaining of several brief episodes of shortness of breath of varying severity. Which of the following substances would lead to a decrease in FEV1 of 20% if the patient has asthma?

Question: Which of the following substances would lead to a decrease in FEV1 of 20% if the patient has asthma?

Answer: Methacholine


Context: A 59-year-old man presents to his primary care physician with a 5-month history of breathing difficulties. He says that he has been experiencing exertional dyspnea that is accompanied by a nonproductive cough. His past medical history is significant for a solitary lung nodule that was removed surgically 10 years ago and found to be benign. He works as a secretary for a coal mining company, does not smoke, and drinks socially with friends. His family history is significant for autoimmune diseases. Physical exam reveals fine bibasilar inspiratory crackles in both lungs, and laboratory testing is negative for antinuclear antibody and rheumatoid factor. Which of the following is associated with the most likely cause of this patient's symptoms?

Question: Which of the following is associated with the most likely cause of this patient's symptoms?

Answer: Subpleural cystic enlargement


Context: A 22-year-old woman comes to the physician because of a 1-month history of persistent abdominal cramping, diarrhea, and rectal pain. During the past 2 weeks, she has had up to 4 small volumed, blood-tinged stools with mucus daily. She has also had intermittent fevers and a 4.5-kg (10-lb) weight loss during this time. She traveled to Southeast Asia 3 months ago and received all appropriate vaccinations and medications beforehand. She has no history of serious illness and takes no medications. Her temperature is 37.2°C (99°F), pulse is 90/min, respirations are 16/min, and blood pressure is 125/80 mm Hg. The abdomen is soft, and there is tenderness to palpation of the left lower quadrant with guarding but no rebound. Bowel sounds are normal. The stool is brown, and a test for occult blood is positive. Flexible sigmoidoscopy shows a granular, hyperemic, and friable rectal mucosa that bleeds easily on contact. Which of the following is this patient at greatest risk of developing?

Question: Which of the following is this patient at greatest risk of developing?

Answer: Colorectal cancer


Context: A 32-year-old man comes to the emergency department because of recurrent episodes of vomiting for 1 day. He has had over 15 episodes of bilious vomiting. During this period he has had cramping abdominal pain but has not had a bowel movement or passed flatus. He does not have fever or diarrhea. He was diagnosed with Crohn disease at the age of 28 years which has been well controlled with oral mesalamine. He underwent a partial small bowel resection for midgut volvulus at birth. His other medications include vitamin B12, folic acid, loperamide, ferrous sulfate, and vitamin D3. He appears uncomfortable and his lips are parched. His temperature is 37.1°C (99.3°F), pulse is 103/min, and blood pressure is 104/70 mm Hg. The abdomen is distended, tympanitic, and tender to palpation over the periumbilical area and the right lower quadrant. Rectal examination is unremarkable. A CT scan of the abdomen shows multiple dilated loops of small bowel with a transition zone in the mid to distal ileum. After 24 hours of conservative management with IV fluid resuscitation, nasogastric bowel decompression, promethazine, and analgesia, his condition does not improve and a laparotomy is scheduled. During the laparotomy, two discrete strictures are noted in the mid-ileum, around 20 cm apart. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Strictureplasty of individual strictures


Context: A 26-year-old gravida 4 para 1 presents to the emergency department with sudden severe abdominal pain and mild vaginal bleeding. Her last menstrual period was 12 weeks ago. She describes her pain as similar to uterine contractions. She has a history of 2 spontaneous abortions in the first trimester. She is not complaining of dizziness or dyspnea. On physical examination, the temperature is 36.9°C (98.4°F), the blood pressure is 120/85 mm Hg, the pulse is 95/min, and the respiratory rate is 17/min. The pelvic examination reveals mild active bleeding and an open cervical os. There are no clots. Transvaginal ultrasound reveals a fetus with no cardiac activity. She is counseled about the findings and the options are discussed. She requests to attempt medical management with mifepristone before progressing to surgical intervention. Which of the following describes the main mechanism of action for mifepristone?

Question: Which of the following describes the main mechanism of action for mifepristone?

Answer: Increase myometrial sensitivity to contractions and induced decidual breakdown


Context: A 57-year-old man presents to his family physician for a routine exam. He feels well and reports no new complaints since his visit last year. Last year, he had a colonoscopy which showed no polyps, a low dose chest computerized tomography (CT) scan that showed no masses, and routine labs which showed a fasting glucose of 93 mg/dL. He is relatively sedentary and has a body mass index (BMI) of 24 kg/m^2. He has a history of using methamphetamines, alcohol (4-5 drinks per day since age 30), and tobacco (1 pack per day since age 18), but he joined Alcoholics Anonymous and has been in recovery, not using any of these for the past 7 years. Which of the following is indicated at this time?

Question: Which of the following is indicated at this time?

Answer: Chest computerized tomography (CT) scan


Context: A 72-year-old man presents to his primary care physician for a wellness visit. He says that he has been experiencing episodes of chest pain and lightheadedness. Approximately 1 week ago he fell to the ground after abruptly getting up from the bed. Prior to the fall, he felt lightheaded and his vision began to get blurry. According to his wife, he was unconscious for about 5 seconds and then spontaneously recovered fully. He experiences a pressure-like discomfort in his chest and lightheadedness with exertion. At times, he also experiences shortness of breath when climbing the stairs. Medical history is significant for hypertension and hypercholesterolemia. He does not smoke cigarettes or drink alcohol. Cardiac auscultation demonstrates a systolic ejection murmur at the right upper border and a normal S1 and soft S2. Which of the following is most likely found in this patient?

Question: Which of the following is most likely found in this patient?

Answer: Increased blood flow velocity through the aortic valve


Context: A 37-year-old G1P1001 presents for her 6-week postpartum visit after delivering a male infant by spontaneous vaginal delivery at 41 weeks and 5 days gestation. She notes that five days ago, her right breast began to hurt, and the skin near her nipple turned red. She also states that she has felt feverish and generally achy for 2 days but thought she was just sleep deprived. The patient’s son has been having difficulty latching for the last 2 weeks and has begun receiving formula in addition to breast milk, though the patient wishes to continue breastfeeding. She is generally healthy with no past medical history but has smoked half a pack per day for the last 15 years. Her mother died from breast cancer at the age of 62, and her father has hypertension and coronary artery disease. At this visit, her temperature is 100.6° F (38.1° C), blood pressure is 116/73 mmHg, pulse is 80/min, and respirations are 14/min. She appears tired and has a slightly flat affect. Examination reveals a 4x4 cm area of erythema on the lateral aspect near the nipple on the right breast. In the center of this area, there is a fluctuant, tender mass that measures 2x2 cm. The overlying skin is intact. The remainder of her exam is unremarkable. Which of the following is the best next step in management?

Question: Which of the following is the best next step in management?

Answer: Needle aspiration and oral dicloxacillin


Context: A 66-year-old woman with hypertension comes to the physician because of crampy, dull abdominal pain and weight loss for 1 month. The pain is located in the epigastric region and typically occurs within the first hour after eating. She has had a 7-kg (15.4-lb) weight loss in the past month. She has smoked 1 pack of cigarettes daily for 20 years. Physical examination shows a scaphoid abdomen and diffuse tenderness to palpation. Laboratory studies including carbohydrate antigen 19-9 (CA 19-9), carcinoembryonic antigen (CEA), and lipase concentrations are within the reference range. Which of the following is the most likely cause of this patient's symptoms?

Question: Which of the following is the most likely cause of this patient's symptoms?

Answer: Narrowing of the celiac artery


Context:
A 56-year-old woman makes an appointment with her physician to discuss the results of her cervical cancer screening. She has been menopausal for  2 years and does not take hormone replacement therapy. Her previous Pap smear showed low-grade squamous intraepithelial lesion (LSIL); no HPV testing was performed. Her gynecologic examination is unremarkable. The results of her current Pap smear is as follows:
Specimen adequacy satisfactory for evaluation
Interpretation low-grade squamous intraepithelial lesion
Notes atrophic pattern
Which option is the next best step in the management of this patient?

Question:
The results of her current Pap smear is as follows:
Specimen adequacy satisfactory for evaluation
Interpretation low-grade squamous intraepithelial lesion
Notes atrophic pattern
Which option is the next best step in the management of this patient?

Answer: Colposcopy


Context: A 19-year-old woman is brought to the physician by her parents because of irritable mood that started 5 days ago. Since then, she has been staying up late at night working on a secret project. She is energetic despite sleeping less than 4 hours per day. Her parents report that she seems easily distracted. She is usually very responsible, but this week she spent her paycheck on supplies for her project. She has never had similar symptoms before. In the past, she has had episodes where she felt too fatigued to go to school and slept until 2 pm every day for 2 weeks at a time. During those times, her parents noticed that she cried excessively, was very indecisive, and expressed feelings of worthlessness. Two months ago, she had an asthma exacerbation and was treated with bronchodilators and steroids. She tried cocaine once in high school but has not used it since. Vital signs are within normal limits. On mental status examination, she is irritable but cooperative. Her speech is pressured and her thought process is linear. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer: Bipolar II disorder


Context: A 36-year-old man presents with massive hematemesis. Past medical history is significant for a gastric ulcer. He has a pulse of 115/min, respiratory rate of 20/min, temperature of 36°C (96.8°F), and blood pressure of 90/59 mm Hg. The patient receives a transfusion of 2 units of packed red blood cells. Around 5–10 minutes after the transfusion, he starts having chills, pain in the lumbar region, and oliguria. His vital signs change to pulse of 118/min, respiratory rate of 19/min, temperature of 38°C (100.4°F), and blood pressure of 60/40 mm Hg. Which of the following is the most likely cause of this patient’s condition?

Question: Which of the following is the most likely cause of this patient’s condition?

Answer: Acute hemolytic transfusion reaction


Context:
A 5-day-old neonate is brought to the pediatrician by his parents for yellow skin for the past few days. His parents also reported that he remains quiet all day and does not even respond to sound. Further perinatal history reveals that he was born by cesarean section at 36 weeks of gestation, and his birth weight was 2.8 kg (6.1 lb). This baby is the second child of this couple, who are close relatives. Their first child died as the result of an infection at an early age. His temperature is 37.0°C (98.6°F), pulse is 116/min, and respirations are 29/min. On physical examination, hypotonia is present. His laboratory studies show:
Hemoglobin 12.9 gm/dL
Leukocyte count 9,300/mm3
Platelet count 170,000/mm3
Unconjugated bilirubin 33 mg/dL
Conjugated bilirubin 0.9 mg/dL
Coombs test Negative
Which of the following is the most appropriate next step?

Question:
His laboratory studies show:
Hemoglobin 12.9 gm/dL
Leukocyte count 9,300/mm3
Platelet count 170,000/mm3
Unconjugated bilirubin 33 mg/dL
Conjugated bilirubin 0.9 mg/dL
Coombs test Negative
Which of the following is the most appropriate next step?

Answer: Liver transplantation


Context: A 5-year-old boy presents to the pediatrician after his parents noted that he could not sustain physical exertion and would experience muscle cramping. It was noted that after physical exertion the boy experienced severe muscle pain. After a series of biochemical and genetic tests, it was discovered the that the boy had a nonsense mutation in the gene encoding the muscle glycogen phosphorylase. Thus he was diagnosed with McArdle's disease. Which of the following mRNA changes would be expected to cause this mutation?

Question: Which of the following mRNA changes would be expected to cause this mutation?

Answer: UAU -> UAA


Context: A 72-year-old man presents to the emergency department with difficulty breathing for the past 3 hours. He also mentions that over the last week he was frequently breathless and fatigued after walking a few blocks. He has had diabetes mellitus and hypertension for the past 10 years, and his regular medications include metformin, glipizide, and lisinopril. However, he did not take his medications last week due to unplanned travel. Review of his medical records reveals an episode of acute viral hepatitis about 6 months ago from which he recovered well. His temperature is 37.0°C (98.6°F), the pulse is 108/min, the blood pressure is 170/94 mm Hg, and the respiratory rate is 24/min. On physical examination, periorbital edema is present with pitting edema over both ankles and pretibial regions. Pallor and icterus are absent. Auscultation of the chest reveals crackles over the infrascapular regions bilaterally. Abdominal examination shows tender hepatomegaly. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer: Acute decompensated heart failure


Context: A 17-year-old girl comes to the physician because of left lower abdominal pain for 1 day. She describes the pain as 6 out of 10 in intensity. Over the past 5 months, she has had similar episodes of pain that occur once a month and last 1 to 2 days. Menses occur at regular 28-day intervals and last 5 to 6 days. Menarche was at the age of 13 years, and her last menstrual period was 2 weeks ago. She has been sexually active with 1 male partner in the past and has used condoms inconsistently. She tested negative for sexually transmitted infections on her last visit 6 months ago. Abdominal and pelvic examination shows no abnormalities. A urine pregnancy test is negative. Which of the following is the most appropriate next step in the management of this patient's symptoms?

Question: Which of the following is the most appropriate next step in the management of this patient's symptoms?

Answer: Reassurance


Context: A 6-month-old boy is brought to the physician for a well-child examination. The boy was born at term, and the pregnancy was complicated by prolonged labor. There is no family history of any serious illnesses. He can sit upright but needs help to do so and cannot roll over from the prone to the supine position. He can pull himself to stand. He can grasp his rattle and can transfer it from one hand to the other. He babbles. He cries if anyone apart from his parents holds him or plays with him. He touches his own reflection in the mirror. Vital signs are within normal limits. He is at the 40th percentile for head circumference, 30th percentile for length, and 40th percentile for weight. Physical examination reveals no abnormalities. Which of the following developmental milestones is delayed in this infant?

Question: Which of the following developmental milestones is delayed in this infant?

Answer: Gross motor


Context: A 30-year-old woman with HIV comes to the emergency department because of fever and multiple skin lesions for 1 week. She also has nausea, anorexia, and abdominal pain. The skin lesions are non-pruritic and painless. She has smoked one pack of cigarettes daily for 15 years and drinks 2 beers daily. She has been using intravenous crack cocaine for 6 years. She appears ill. Her temperature is 38°C (100.4°F), pulse is 105/min, blood pressure is 110/75 mm Hg. Her BMI is 19 kg/m2. Examination shows track marks on both cubital fossae. There are white patches on her palate that can be scraped off. There are several red papules measuring 1 to 2 cm on her face and trunk. Her CD4+T-lymphocyte count is 98/mm3 (N ≥ 500). Biopsy of a skin lesion shows vascular proliferation and small black bacteria on Warthin-Starry stain. Which of the following is the most appropriate pharmacotherapy?

Question: Which of the following is the most appropriate pharmacotherapy?

Answer: Erythromycin


Context:
A 63-year-old man presents to the emergency department because of progressive difficulty with breathing. He has a history of diabetes, hypertension, and chronic bronchitis. He has been receiving medications to moderate his conditions and reports being compliant with his schedule. He reports a recent difficulty with tackling simple chores in the house. He has not been able to walk for more than 1 block over the past few days. His persistent cough has also been worsening with more formation of sputum. During his diagnosis of bronchitis, about a year ago, he had a 40-pack-year smoking history. The patient is in evident distress and uses his accessory muscles to breathe. The vital signs include: temperature 38.6°C (101.5°F), blood pressure 120/85 mm Hg, pulse 100/min, respiratory rate 26/min, and oxygen (O2) saturation 87%. A decrease in breathing sounds with expiratory wheezes is heard on auscultation of the heart. The arterial blood gas (ABG) analysis shows:
PCO2 60 mm Hg
PO2 45 mm Hg
pH 7.3
HCO3– 25 mEq/L
Which of the following is the most appropriate next step in the treatment?

Question:
The arterial blood gas (ABG) analysis shows:
PCO2 60 mm Hg
PO2 45 mm Hg
pH 7.3
HCO3– 25 mEq/L
Which of the following is the most appropriate next step in the treatment?

Answer: O2 supplementation


Context: A 7-year-old girl is brought to the physician for a well-child examination. She is at 95th percentile for height and 70th percentile for weight. Examination shows elevated breast buds that extend beyond the areola. Coarse pubic and axillary hair is present. The external genitalia appear normal. An x-ray of the left wrist shows a bone age of 10 years. Serum luteinizing hormone levels do not increase following GnRH agonist stimulation. Which of the following is the most likely cause of these findings?

Question: Which of the following is the most likely cause of these findings?

Answer: Granulosa cell tumor


Context: A researcher is investigating the effects of a new antihypertensive medication on renal physiology. She gives a subject a dose of the new medication, and she then collects plasma and urine samples. She finds the following: Hematocrit: 40%; Serum creatinine: 0.0125 mg/mL; Urine creatinine: 1.25 mg/mL. Urinary output is 1 mL/min. Renal blood flow is 1 L/min. Based on the above information and approximating that the creatinine clearance is equal to the GFR, what answer best approximates filtration fraction in this case?

Question: Based on the above information and approximating that the creatinine clearance is equal to the GFR, what answer best approximates filtration fraction in this case?

Answer: 17%


Context: A 71-year-old man with asthma and dementia presents to the emergency department in acute respiratory distress. He is with his home care nurse who explains that he has been hiding his bronchodilators for the past 3 weeks, and she has had to dutifully look for them and help him administer them. Over the past 2 days, however, she has been completely unsuccessful in finding his medication and was in the process of contacting his primary care physician for a refill of his prescription when he suddenly had a ‘coughing fit’ and began wheezing uncontrollably. The patient is obviously uncomfortable and is using accessory muscles of respiration to catch his breath. He is struggling to speak and is immediately given multiple doses of nebulized albuterol and intravenous methylprednisolone; however, his condition does not improve. The arterial blood gas test result shows pH 7.20. He is subsequently intubated and sent to the intensive care unit (ICU). In patients who are intubated for mechanical ventilation, there is an increased risk for ventilator-associated pneumonia. Which of the following should be prophylactically given to this patient to lower his risk for pneumonia?

Question: Which of the following should be prophylactically given to this patient to lower his risk for pneumonia?

Answer: Sucralfate


Context: The serum brain natriuretic peptide and N-terminal pro-BNP are elevated. A diagnosis of heart failure with preserved ejection fraction is made. In addition to supplemental oxygen therapy, which of the following is the most appropriate initial step in management?

Question: In addition to supplemental oxygen therapy, which of the following is the most appropriate initial step in management?

Answer:
Intravenous furosemide therapy
"


Context: A 53-year-old female presents with worsening shortness of breath with activity. Physical exam reveals a diastolic murmur with an opening snap. The patient’s medical history is significant for a left hip replacement 10 years ago, and she vaguely recalls an extended period of illness as a child described as several severe episodes of sore throat followed by rash, fever, and joint pains. Administration of which of the following treatments at that time would have been most effective in reducing her risk of developing cardiac disease?

Question: Administration of which of the following treatments at that time would have been most effective in reducing her risk of developing cardiac disease?

Answer: Penicillin


Context: A 69-year-old woman with acute myeloid leukemia comes to the physician to discuss future treatment plans. She expresses interest in learning more about an experimental therapy being offered for her condition. After the physician explains the mechanism of the drug and describes the risks and benefits, the patient then states that she is not ready to die. When the physician asks her what her understanding of the therapy is, she responds “I don't remember the details, but I just know that I definitely want to try it, because I don't want to die.” Which of the following ethical principles is compromised in this physicians' interaction with the patient?

Question: When the physician asks her what her understanding of the therapy is, she responds “I don't remember the details, but I just know that I definitely want to try it, because I don't want to die.” Which of the following ethical principles is compromised in this physicians' interaction with the patient?

Answer: Decision-making capacity


Context: A 22-year-old man has had dyspnea and hemoptysis for the past week. He has no known sick contacts. There is no personal or family history of serious illness. He takes no medications. His temperature is 37°C (98.6°F), pulse is 82/min, respirations are 22/min, and blood pressure is 152/90 mm Hg. Examination shows inspiratory crackles at both lung bases. The remainder of the examination shows no abnormalities. His hemoglobin is 14.2 g/dL, leukocyte count is 10,300/mm3, and platelet count is 205,000/mm3. Urinalysis shows a proteinuria of 2+, 70 RBC/hpf, and 1–2 WBC/hpf. Chest x-ray shows pulmonary infiltrates. Further evaluation is most likely to show which of the following findings?

Question: Further evaluation is most likely to show which of the following findings?

Answer: Increased anti-GBM antibody titers


Context: A 62-year-old man comes to the emergency department for severe, acute right leg pain. The patient's symptoms began suddenly 4 hours ago, while he was reading the newspaper. He has poorly-controlled hypertension and osteoarthritis. He has smoked one pack of cigarettes daily for 31 years. Current medications include lisinopril, metoprolol succinate, and ibuprofen. He appears to be in severe pain and is clutching his right leg. His temperature is 37.4°C (99.3°F), pulse is 102/min and irregularly irregular, respirations are 19/min, and blood pressure is 152/94 mm Hg. The right leg is cool to the touch, with decreased femoral, popliteal, posterior tibial, and dorsalis pedis pulses. There is moderate weakness and decreased sensation in the right leg. An ECG shows absent P waves and a variable R-R interval. Right leg Doppler study shows inaudible arterial signal and audible venous signal. Angiography shows 90% occlusion of the right common femoral artery. In addition to initiating heparin therapy, which of the following is the most appropriate next step in management?

Question: In addition to initiating heparin therapy, which of the following is the most appropriate next step in management?

Answer: Balloon catheter embolectomy


Context: A 45-year-old man comes to the physician because of intermittent lower back pain for 1 week. His symptoms began shortly after lifting heavy boxes at work. He has not had any fever, chills, or weight loss. He has a history of peptic ulcer disease. He does not smoke or drink alcohol. His vital signs are within normal limits. Examination shows mild paraspinal lumbar tenderness. Neurologic examination shows no focal findings. An x-ray of the spine shows no abnormalities. Which of the following is the most appropriate initial pharmacotherapy?

Question: Which of the following is the most appropriate initial pharmacotherapy?

Answer: Acetaminophen


Context:
A 30-year-old man presents to his primary care physician complaining of headaches. He states that over the past month he has been trying to study for an accounting exam, but he finds it increasingly more difficult to focus due to his headaches. He also complains of lower extremity muscle cramping. He has no significant past medical history and takes ibuprofen and acetaminophen as needed. The patient’s temperature is 98°F (36.7°C), blood pressure is 168/108 mmHg, and pulse is 75/min. Labs are obtained, as shown below:

Serum:
pH (VBG): 7.50
Na: 146 mEq/L
K+: 3.2 mEq/L
Cl-: 104 mEq/L
HCO3-: 32 mEq/L
Urea nitrogen: 20 mg/dL
Creatinine: 1.1 mg/dL
Glucose: 85 mg/dL

An ultrasound reveals a hypoechoic lesion within the right adrenal gland. A 2 cm right-sided homogeneous adrenal mass is confirmed with computed tomography. Which of the following findings is associated with the patient’s most likely diagnosis?

Question: Which of the following findings is associated with the patient’s most likely diagnosis?

Answer: Low plasma renin


Context: A 66-year-old woman presents to the emergency department with a throbbing headache. She states that the pain is worse when eating and is localized over the right side of her head. Review of systems is only notable for some blurry vision in the right eye which is slightly worse currently. The patient's past medical history is notable only for chronic pain in her muscles and joints for which she has been taking ibuprofen. Her temperature is 99.1°F (37.3°C), blood pressure is 144/89 mmHg, pulse is 87/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical examination is significant for tenderness to palpation over the right temporal region. Which of the following is the best initial step in management?

Question: Which of the following is the best initial step in management?

Answer: Methylprednisolone


Context:
A 72-year-old Caucasian female presents to the emergency department with complaints of a new-onset, right-sided throbbing headache which becomes markedly worse when eating. The daughter also reports that her mother has recently had difficulties with performing daily activities, such as climbing stairs or standing up. Past medical history is significant for a lower extremity deep vein thrombosis. The blood pressure is 124/78 mm Hg, the heart rate is 72/min, and the respiratory rate is 15/min. The physical examination is unremarkable except for the right visual field defect. Laboratory results are presented below:
Hemoglobin 11.3 g/dL
Hematocrit 37.7%
Leukocyte count 6,200/mm3
Mean corpuscular volume 82.2 μm3
Platelet count 200,000/mm3
Erythrocyte sedimentation rate 75 mm/h
C-reactive protein 50 mg/dL
Which of the following medications would be most beneficial for this patient?

Question:
Laboratory results are presented below:
Hemoglobin 11.3 g/dL
Hematocrit 37.7%
Leukocyte count 6,200/mm3
Mean corpuscular volume 82.2 μm3
Platelet count 200,000/mm3
Erythrocyte sedimentation rate 75 mm/h
C-reactive protein 50 mg/dL
Which of the following medications would be most beneficial for this patient?

Answer: Prednisolone


Context: A 29-year-old woman presents to the office with the complaint of a tingling sensation over her face and distal parts of her lower limbs. Three weeks ago, she had an episode of bloody diarrhea and was successfully treated with erythromycin. She is a full-time radiology technician. Currently, she takes oral contraceptives and zopiclone (1 mg) at bedtime. Her blood pressure is 100/80 mm Hg, her heart rate is 91/min, her respiratory rate is 15/min, and her temperature is 36.7°C (98.0°F). Neurological examination reveals loss of all sensation over the face and in the distal part of her lower limbs. Strength in calf flexor and extensor muscles is diminished bilaterally (4/5 on all of the muscle groups). Deep tendon reflexes are 1+ in the knees and 1+ in the ankles. Plantar reflexes are flexor. What is the most probable mechanism of the pathological findings in this patient?

Question: What is the most probable mechanism of the pathological findings in this patient?

Answer: Antibody-mediated destruction of peripheral myelin by cytotoxic cells


Context: A 12-year-old girl is brought to the physician by her mother 2 hours after cutting her hand while playing in the yard. Examination of the right hand shows a 2-cm laceration on the thenar region of the palm with some surrounding tenderness and erythema. The right palm appears mildly swollen in comparison to the left. In response to this patient's injury, the endothelial cells lining the blood vessels of the affected area express increased numbers of cellular adhesion molecules. Which of the following mediators is most likely directly responsible for the described change?

Question: Which of the following mediators is most likely directly responsible for the described change?

Answer: Interleukin-1


Context: A 3-week-old male is brought to the emergency department because of increasing lethargy. He was born at home without prenatal care or neonatal screening and appeared to be normal at birth. Despite this, his parents noticed that he would vomit after breastfeeding. He then progressively became more lethargic and began to have a few episodes of diarrhea after feeding. His parents do not recall any significant family history and neither of his siblings have had similar symptoms. Upon presentation, the infant is found to be generally unresponsive with mild hepatomegaly. Physical exam further reveals signs of clouding in the lenses of his eyes bilaterally. The levels of which of the following metabolites will be most dramatically elevated in this patient?

Question: The levels of which of the following metabolites will be most dramatically elevated in this patient?

Answer: Galactose-1-phosphate


Context: A 7-year-old boy is brought to the physician by his mother for the evaluation of abdominal pain and trouble sleeping for the past 6 months. His mother says he complains of crampy abdominal pain every morning on school days. He started attending a new school 7 months ago and she is concerned because he has missed school frequently due to the abdominal pain. He also has trouble falling asleep at night and asks to sleep in the same room with his parents every night. He has not had fever, vomiting, diarrhea, or weight loss. He sits very close to his mother and starts to cry when she steps out of the room to take a phone call. Abdominal examination shows no abnormalities. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer: Separation anxiety disorder


Context: A 69-year old male presents to the Emergency Department with bilious vomiting that started within the past 24 hours. His medical history is significant for hypertension, hyperlipidemia, and a myocardial infarction six months ago. His past surgical history is significant for a laparotomy 20 years ago for a perforated diverticulum. Most recently he had some dental work done and has been on narcotic pain medicine for the past week. He reports constipation and obstipation. He is afebrile with a blood pressure of 146/92 mm Hg and a heart rate of 116/min. His abdominal exam reveals multiple well-healed scars with distension but no tenderness. An abdominal/pelvic CT scan reveals dilated small bowel with a transition point to normal caliber bowel distally. When did the cause of his pathology commence?

Question: When did the cause of his pathology commence?

Answer: 20 years ago


Context: A 52-year-old woman comes to the physician because of vaginal itchiness and urinary frequency for the past 1 year. She stopped having vaginal intercourse with her husband because it became painful and occasionally resulted in vaginal spotting. Her last menstrual cycle was 14 months ago. She has vitiligo. Her only medication is a topical tacrolimus ointment. Her temperature is 37.1°C (98.8°F), pulse is 85/min, and blood pressure is 135/82 mm Hg. Examination shows multiple white maculae on her forearms, abdomen, and feet. Pelvic examination shows scarce pubic hair, vulvar pallor, and narrowing of the vaginal introitus. Which of the following most likely contributes to this patient's current symptoms?

Question: Which of the following most likely contributes to this patient's current symptoms?

Answer: Thinning of the mucosa


Context: A 26-year-old woman presents to the obstetrics ward to deliver her baby. The obstetrician establishes a pudendal nerve block via intravaginal injection of lidocaine near the tip of the ischial spine. From which of the following nerve roots does the pudendal nerve originate?

Question: From which of the following nerve roots does the pudendal nerve originate?

Answer: S2-S4


Context: A 25-year-old woman presents to her primary care physician for her yearly physical exam. She has no past medical history and says that she does not currently have any health concerns. On physical exam, she is found to have hyperactive patellar reflexes but says that she has had this finding since she was a child. She asks her physician why this might be the case. Her physician explains that there are certain cells that are responsible for detecting muscle stretch and responding to restore the length of the muscle. Which of the following is most likely a characteristic of these structures?

Question: Which of the following is most likely a characteristic of these structures?

Answer: They are in parallel with extrafusal skeletal muscle fibers


Context: A 3-month-old boy is brought to the physician for a routine follow-up examination. He was delivered at 32 weeks' gestation to a 35-year-old woman. Cardiac examination is shown. Which of the following is the most likely cause for this patient's findings?

Question: Which of the following is the most likely cause for this patient's findings?

Answer: Patent ductus arteriosus


Context:
A 61-year-old woman is brought to an urgent care clinic by her husband with an altered mental status. The patient’s husband says that her symptoms onset acutely 24 hours ago. He says she suddenly started to feel excessively drowsy and quickly became altered. Past medical history is significant for renal transplant 18 months ago, well-managed with immunosuppressive medication. The vital signs include: temperature 39.4°C (103.0°F), blood pressure 85/50 mm Hg, pulse 135/min and respirations 24/min. On physical examination, the patient is arousable but non-responsive to commands. Oriented x 0. Glasgow Coma Scale (GCS) score is 10/15. Multiple black skin lesions are present on the trunk. Lesions are approximately 4 cm is diameter and round with a necrotic center forming an eschar. Laboratory findings are significant for the following:
Hemoglobin 14.2 g/dL
WBC count 3,700/µL
Neutrophils 22%
Lymphocytes 52%
Monocytes 17%
Eosinophils 5%
Basophils 4%
Platelets 179,000/µL
BUN 15 mg/dL
Creatinine 0.8 mg/dL
Blood cultures are positive for Pseudomonas aeruginosa. Which of the following factors is most likely responsible for this patient’s condition?

Question: Which of the following factors is most likely responsible for this patient’s condition?

Answer: Decreased phagocytic cell count


Context:
A 44-year-old male is brought to the emergency department by fire and rescue after he was the unrestrained driver in a motor vehicle accident. His wife notes that the patient’s only past medical history is recent development of severe episodes of headache accompanied by sweating and palpitations. She says that these episodes were diagnosed as atypical panic attacks by the patient’s primary care provider, and the patient was started on sertraline and alprazolam. In the trauma bay, the patient’s temperature is 97.6°F (36.4°C), blood pressure is 81/56 mmHg, pulse is 127/min, and respirations are 14/min. He has a Glascow Coma Score (GCS) of 10. He is extremely tender to palpation in the abdomen with rebound and guarding. His skin is cool and clammy, and he has thready peripheral pulses. The patient's Focused Assessment with Sonography for Trauma (FAST) exam reveals bleeding in the perisplenic space, and he is taken for emergency laparotomy. He is found to have a ruptured spleen, and his spleen is removed. During manipulation of the bowel, the patient’s temperature is 97.8°F (36.6°C), blood pressure is 246/124 mmHg, and pulse is 104/min. The patient is administered intravenous labetalol, but his blood pressure continues to worsen. The patient dies during the surgery.

Which of the following medications would most likely have prevented this outcome?

Question: Which of the following medications would most likely have prevented this outcome?

Answer: Phenoxybenzamine


Context: A 44-year-old man comes to the emergency department because of a severe headache and blurry vision for the past 3 hours. He has hypertension treated with hydrochlorothiazide. He has missed taking his medication for the past week as he was traveling. He is only oriented to time and person. His temperature is 37.1°C (98.8°F), pulse is 92/min and regular, and blood pressure is 245/115 mm Hg. Cardiopulmonary examination shows no abnormalities. Fundoscopy shows bilateral retinal hemorrhages and exudates. Neurologic examination shows no focal findings. A complete blood count and serum concentrations of electrolytes, glucose, and creatinine are within the reference range. A CT scan of the brain shows no abnormalities. Which of the following is the most appropriate pharmacotherapy?

Question: Which of the following is the most appropriate pharmacotherapy?

Answer: Intravenous nitroprusside


Context:
A 65-year-old man is brought to the emergency department by ambulance after falling during a hiking trip. He was hiking with friends when he fell off a 3 story ledge and was not able to be rescued until 6 hours after the accident. On arrival, he is found to have multiple lacerations as well as a pelvic fracture. His past medical history is significant for diabetes and benign prostatic hyperplasia, for which he takes metformin and prazosin respectively. Furthermore, he has a family history of autoimmune diseases. Selected lab results are shown below:

Serum:
Na+: 135 mEq/L
Creatinine: 1.5 mg/dL
Blood urea nitrogen: 37 mg/dL

Urine:
Na+: 13.5 mEq/L
Creatinine: 18 mg/dL
Osmolality: 580 mOsm/kg

Which of the following is the most likely cause of this patient's increased creatinine level?

Question:
Selected lab results are shown below:

Serum:
Na+: 135 mEq/L
Creatinine: 1.5 mg/dL
Blood urea nitrogen: 37 mg/dL

Urine:
Na+: 13.5 mEq/L
Creatinine: 18 mg/dL
Osmolality: 580 mOsm/kg

Which of the following is the most likely cause of this patient's increased creatinine level?

Answer: Blood loss


Context: A 2-year-old boy is brought to the emergency department because of fever, fatigue, and productive cough for 2 days. He had similar symptoms 6 months ago, when he was diagnosed with pneumonia. Three weeks ago, he was diagnosed with otitis media for the sixth time since his birth and was treated with amoxicillin. His temperature is 38.7°C (101.7°F), pulse is 130/min, respirations are 36/min, and blood pressure is 84/40 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 93%. Examination shows purulent discharge in the left ear canal and hypoplastic tonsils without exudate. Coarse crackles are heard over the right lung field on auscultation. An x-ray of the chest shows a right middle lobe consolidation. Flow cytometry shows absent B cells and normal T cells. Which of the following is the most appropriate next step in management?

Question: Which of the following is the most appropriate next step in management?

Answer: Intravenous immunoglobulins


Context: A 17-year-old woman presents to the emergency department with dysuria. She denies any hematuria or dyspareunia. Her last menstrual period was 3 weeks ago, and she denies any recent sexual activity. Her temperature is 99.7°F (37.6°F), blood pressure is 127/67 mmHg, pulse is 90/min, and respirations are 17/min. An unusual odor is detected on inspection of the vagina and some gray discharge is noted. Speculum exam reveals a normal cervix and a bimanual exam is unremarkable for adnexal masses or tenderness. What is the next best step in management?

Question: What is the next best step in management?

Answer: Urinalysis, urine culture, KOH prep, and urine pregnancy test


Context: A 24-year-old man is brought to the emergency department because of violent jerky movements of his arms and legs that began 30 minutes ago. His father reports that the patient has a history of epilepsy. He is not responsive. Physical examination shows alternating tonic jerks and clonic episodes. There is blood in the mouth. Administration of intravenous lorazepam is begun. In addition, treatment with a second drug is started that alters the flow of sodium ions across neuronal membranes. The second agent administered was most likely which of the following drugs?

Question: The second agent administered was most likely which of the following drugs?

Answer: Fosphenytoin


Context: A 16-year-old girl is brought to the physician because of generalized fatigue and an inability to concentrate in school for the past 4 months. During this period, she has had excessive daytime sleepiness. While going to sleep, she sees cartoon characters playing in her room. She wakes up once or twice every night. While awakening, she feels stiff and cannot move for a couple of minutes. She goes to sleep by 9 pm every night and wakes up at 7 am. She takes two to three 15-minute naps during the day and wakes up feeling refreshed. During the past week while listening to a friend tell a joke, she had an episode in which her head tilted and jaw dropped for a few seconds; it resolved spontaneously. Her father has schizoaffective disorder and her parents are divorced. Vital signs are within normal limits. Physical examination is unremarkable. Which of the following is the most appropriate initial pharmacotherapy?

Question: Which of the following is the most appropriate initial pharmacotherapy?

Answer: Modafinil


Context: A 24-year-old woman presents to the emergency department for chest pain and shortness of breath. She was at home making breakfast when her symptoms began. She describes the pain as sharp and located in her chest. She thought she was having a heart attack and began to feel short of breath shortly after. The patient is a college student and recently joined the soccer team. She has no significant past medical history except for a progesterone intrauterine device which she uses for contraception, and a cyst in her breast detected on ultrasound. Last week she returned on a trans-Atlantic flight from Russia. Her temperature is 98.4°F (36.9°C), blood pressure is 137/69 mmHg, pulse is 98/min, respirations are 18/min, and oxygen saturation is 99% on room air. Physical exam reveals an anxious young woman. Cardiac and pulmonary exam are within normal limits. Deep inspiration and palpation of the chest wall elicits pain. Neurologic exam reveals a stable gait and cranial nerves II-XII are grossly intact. Which of the following best describes the most likely underlying etiology?

Question: Which of the following best describes the most likely underlying etiology?

Answer: Musculoskeletal inflammation


Context: A 26-year-old nursing home staff presents to the emergency room with complaints of palpitations and chest pain for the past 2 days. She was working at the nursing home for the last year but has been trying to get into modeling for the last 6 months and trying hard to lose weight. She is a non-smoker and occasionally drinks alcohol on weekends with friends. On examination, she appears well nourished and is in no distress. The blood pressure is 150/84 mm Hg and the pulse is 118/min. An ECG shows absent P waves. All other physical findings are normal. What is the probable diagnosis?

Question: What is the probable diagnosis?

Answer: Factitious thyrotoxicosis


Context: You are taking care of a patient with renal failure secondary to anti-fungal therapy. The patient is a 66-year-old male being treated for cryptococcal meningitis. This drug has a variety of known side effects including acute febrile reactions to infusions, anemia, hypokalemia and hypomagnesemia. What is the mechanism of action of of this drug?

Question: What is the mechanism of action of of this drug?

Answer: Pore formation secondary to ergosterol binding


Context: A 65-year-old man presents to the physician for the evaluation of increasing dyspnea and swelling of the lower extremities over the past year. He has no cough. He also complains of frequent awakenings at night and excessive daytime sleepiness. He has no history of a serious illness. He takes no medications other than zolpidem before sleep. He is a 35-pack-year smoker. His blood pressure is 155/95 mm Hg. His BMI is 37 kg/m2. Oropharyngeal examination shows a small orifice and an enlarged tongue and uvula. The soft palate is low-lying. The examination of the nasal cavity shows no septal deviation or polyps. Symmetric pitting edema is seen below the knee, bilaterally. The lungs are clear to auscultation. Echocardiography shows a mildly dilated right ventricle and an elevated systolic pulmonary artery pressure with no abnormalities of the left heart. A ventilation-perfusion scan shows no abnormalities. Which of the following is the most likely cause of this patient’s symptoms?

Question: Which of the following is the most likely cause of this patient’s symptoms?

Answer: Obstructive sleep apnea


Context:
A 43-year-old man comes to the physician for a follow-up examination. Four months ago, he was treated conservatively for ureteric colic. He has noticed during micturition that his urine is reddish-brown initially and then clears by the end of the stream. He has no dysuria. He has hypertension. His only medication is hydrochlorothiazide. He appears healthy and well-nourished. His temperature is 37°C (98.6°F), pulse is 80/min, and blood pressure is 122/86 mm Hg. Physical examination shows no abnormalities. Laboratory studies show:
Hemoglobin 14.1 g/dL
Serum
Glucose 88 mg/dL
Creatinine 0.6 mg/dL
Urine
Blood 2+
Protein negative
Leukocyte esterase negative
Nitrite negative
RBCs 5–7/hpf
WBCs 0–1/hpf
RBC casts none
Which of the following is the most likely origin of this patient's hematuria?"

Question:
Laboratory studies show:
Hemoglobin 14.1 g/dL
Serum
Glucose 88 mg/dL
Creatinine 0.6 mg/dL
Urine
Blood 2+
Protein negative
Leukocyte esterase negative
Nitrite negative
RBCs 5–7/hpf
WBCs 0–1/hpf
RBC casts none
Which of the following is the most likely origin of this patient's hematuria?"

Answer: Urethra


Context: A 15-year-old African-American boy is brought to the physician because of left-sided groin pain and difficulty walking for 3 weeks. He reports having pain at rest and increased pain with activity. He recently started playing flag football but does not recall any trauma. He has had many episodes of joint and bone pain that required hospitalization in the past. He is at the 25th percentile for height and 20th percentile for weight. His temperature is 37°C (98.6°F), blood pressure is 120/80 mm Hg, and pulse is 90/min. Examination shows tenderness over the lateral aspect of the hip with no swelling, warmth, or erythema. There is pain with passive internal rotation of the left hip. The remainder of the examination shows no abnormalities. Leukocyte count is 9,000/mm3. Which of the following conditions is the most likely cause of the patient's current symptoms?

Question: Which of the following conditions is the most likely cause of the patient's current symptoms?

Answer: Avascular necrosis


Context: A 36-year-old primigravid woman comes to the physician for a prenatal visit at 14 weeks' gestation. She has had episodic headaches over the past month. At home, blood pressure measurements have ranged from 134/82 mm Hg to 148/94 mm Hg. Today, her blood pressure is 146/91 mm Hg. Pelvic examination shows a uterus consistent in size with a 13-week gestation. Serum creatinine is 0.8 mg/dL, serum ALT is 17 U/L, and platelet count is 320,000/mm3. Urinalysis shows no abnormalities. Which of the following is the most likely diagnosis?

Question: Which of the following is the most likely diagnosis?

Answer: Chronic hypertension