Context: A 7-month-old boy presents to the family physician with extensive scaliness and pigmentation of sun-exposed skin areas. His mother says that these symptoms were absent until mid-spring and then became significantly worse after their trip to California in the summer. The child was born in December to a consanguineous couple after an uncomplicated pregnancy. He is breastfed and receives mashed potatoes, bananas, and carrots as complementary foods. His weight is 8.5 kg (18.7 lb) and length is 70 cm (2 ft 96 in). The patient’s vital signs are within normal limits for his age. On physical examination, there is freckling, scaling, and erythema on the sunlight-exposed areas of the face, trunk, and upper and lower extremities. No blistering, scarring, hypertrichosis, or alopecia is noted. The rest of the exam is unremarkable. Which process is most likely disrupted in this patient?

Question: Which process is most likely disrupted in this patient?

Answer: Nucleotide-excision DNA repair


Context: A 34-year-old woman with no significant prior medical history presents to the clinic with several days of bloody stool. She also complains of constipation and straining, but she has no other symptoms. She has no family history of colorectal cancer or inflammatory bowel disease. She does not smoke or drink alcohol. Her vital signs are as follows: blood pressure is 121/81 mm Hg, heart rate is 77/min, and respiratory rate is 15/min. There is no abdominal discomfort on physical exam, and a digital rectal exam reveals bright red blood. Of the following, which is the most likely diagnosis?

Question: Of the following, which is the most likely diagnosis?

Answer: Internal hemorrhoids


Context:
A 53-year-old man comes to the physician because of fatigue, recurrent diarrhea, and an 8-kg (17.6-lb) weight loss over the past 6 months. He has a 4-month history of recurrent blistering rashes on different parts of his body that grow and develop into pruritic, crusty lesions before resolving spontaneously. Physical examination shows scaly lesions in different phases of healing with central, bronze-colored induration around the mouth, perineum, and lower extremities. Laboratory studies show:
Hemoglobin 10.1 mg/dL
Mean corpuscular volume 85 μm3
Mean corpuscular hemoglobin 30.0 pg/cell
Serum
Glucose 236 mg/dL
Abdominal ultrasonography shows a 3-cm, solid mass located in the upper abdomen. This patient's mass is most likely derived from which of the following types of cells?"

Question: This patient's mass is most likely derived from which of the following types of cells?"

Answer: Pancreatic α-cells


Context: A 42-year-old man presents to his primary care provider complaining of foamy urine for the last 2 weeks. He has also begun to notice swelling in his hands and feet, and he says that his shoes have not been fitting normally. On exam, the patient has a temperature of 98.8°F (37.1°C), blood pressure is 132/84 mmHg, pulse is 64/min, and respirations are 12/min. The patient has 2+ pitting edema bilaterally up to his shins. A 24-hour urine study is found to contain 9.0 g of protein. The patient is referred to a specialist and undergoes a renal biopsy. On light microscopy, the glomeruli demonstrate basement membrane thickening. On electron microscopy, subepithelial deposits are seen. Which of the following is a characteristic of this patient’s disease?

Question: Which of the following is a characteristic of this patient’s disease?

Answer: Antibodies to phospholipase A2 receptor


Context: A 72-year-old woman is brought to the emergency department because of severe pain in her left hip after a fall this morning. She has smoked one pack of cigarettes daily for 45 years. Her only medication is a vitamin D supplement. Physical examination shows that her left leg is externally rotated and appears shorter than her right leg. An x-ray of the pelvis shows a fracture of the neck of the left femur. Which of the following changes in bone architecture is the most likely underlying cause of this patient's symptoms?

Question: Which of the following changes in bone architecture is the most likely underlying cause of this patient's symptoms?

Answer: Loss of cortical bone mass and thinning of trabeculae


Context:
A 69-year-old woman comes to the physician because of lower back pain and right-sided chest pain for the past month. The pain is aggravated by movement. Over the past 2 months, she has had increasing fatigue. Her mother died of breast cancer. She has hypertension and reflux disease. Current medications include metoprolol and omeprazole. Vital signs are within normal limits. Examination shows full muscle strength. There is tenderness to palpation over the lower spine and the right lateral chest. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 9.5 g/dL
Leukocyte count 7,300/mm3
Platelet count 230,000/mm3
Serum
Na+ 137 mEq/L
K+ 3.5 mEq/L
Creatinine 1.3 mg/dL
An ECG shows no evidence of ischemia. An x-ray of the chest shows lytic lesions in 2 ribs. Blood smear shows aggregations of erythrocytes. Protein electrophoresis of the serum with immunofixation shows an M-protein spike. This patient's condition is most likely associated with which of the following findings?"

Question: This patient's condition is most likely associated with which of the following findings?"

Answer: Urinary tract infection


Context: A 68-year-old man comes to the physician because of a 6-month history of difficulty swallowing pieces of meat and choking frequently during meal times. He also sometimes regurgitates foul-smelling, undigested food particles. Examination shows a 3 x 3 cm soft cystic, immobile mass in the upper third of the left side of his neck anterior to the left sternocleidomastoid muscle that becomes prominent when he coughs. A barium swallow shows an accumulation of contrast on the lateral aspect of the neck at the C5 level. Which of the following is the most likely underlying cause for this patient's condition?

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

Answer: Increased intrapharyngeal pressure


Context: A 67-year-old male with a history of poorly controlled hypertension, COPD, and diabetes presents to his cardiologist for a routine appointment. He reports that he has no current complaints and has not noticed any significant changes in his health. On exam, the cardiologist hears an extra heart sound in late diastole that immediately precedes S1. This heart sound is most associated with which of the following?

Question: This heart sound is most associated with which of the following?

Answer: Left ventricular hypertrophy


Context:
A 42-year-old woman comes to the physician because of increasing fatigue and difficulty concentrating at work for the last 2 months. She has hypertension and a 22-year history of Crohn disease. She has been hospitalized and treated for acute exacerbations, sometimes involving strictures, multiple times in the past. She has not had significant gastrointestinal symptoms in over a year. Current medications include mesalamine, thiazide, and bisoprolol. Her temperature is 37.2°C (99°F), pulse is 72/min, and blood pressure is 140/90 mm Hg. Examination shows a soft abdomen and pale conjunctivae. Rectal examination is unremarkable. Laboratory studies show:
Hemoglobin 9.4 g/dL
Mean corpuscular volume 112 fL
Mean corpuscular hemoglobin 37.2 pg/cell
Leukocyte count 8,700 /mm3
Platelet count 150,000 /mm3
Erythrocyte sedimentation rate 42 mm/h
Serum
Ferritin 88 ng/mL
Iron 117 μg/dL
Thyroid-stimulating hormone 3.2 μU/mL
Thyroxine 7 μg/dL
Further evaluation of this patient is most likely to reveal which of the following findings?"

Question:
Laboratory studies show:
Hemoglobin 9.4 g/dL
Mean corpuscular volume 112 fL
Mean corpuscular hemoglobin 37.2 pg/cell
Leukocyte count 8,700 /mm3
Platelet count 150,000 /mm3
Erythrocyte sedimentation rate 42 mm/h
Serum
Ferritin 88 ng/mL
Iron 117 μg/dL
Thyroid-stimulating hormone 3.2 μU/mL
Thyroxine 7 μg/dL
Further evaluation of this patient is most likely to reveal which of the following findings?"

Answer: Decreased vibratory sensation


Context: A resident in the department of obstetrics and gynecology is reading about a randomized clinical trial from the late 1990s that was conducted to compare breast cancer mortality risk, disease localization, and tumor size in women who were randomized to groups receiving either annual mammograms starting at age 40 or annual mammograms starting at age 50. One of the tables in the study compares the two experimental groups with regard to socioeconomic demographics (e.g., age, income), medical conditions at the time of recruitment, and family history of breast cancer. The purpose of this table is most likely to evaluate which of the following?

Question: The purpose of this table is most likely to evaluate which of the following?

Answer: Randomization


Context: A 56-year-old man is seen in the hospital for a chief complaint of intense thirst and polyuria. His history is significant for recent transsphenoidal resection of a pituitary adenoma. With regard to the man's fluid balance, which of the following would be expected?

Question: With regard to the man's fluid balance, which of the following would be expected?

Answer: Increased extracellular fluid osmolarity


Context:
An 82-year-old man presents with painless swelling of the neck for the past week. He reports no recent fever, night sweats, or weight loss. He has no significant medical history, and his only medication is daily aspirin. His temperature is 36.8℃ (98.2℉). On physical examination, there are several non-tender lymph nodes, each averaging 2 cm in diameter, which are palpable in the right anterior cervical triangle. No other palpable lymphadenopathy is noted. The remainder of the physical exam is unremarkable. Laboratory studies show the following:
Hemoglobin 10 g/dL
Leukocyte count 8000/mm3 with a normal differential
Platelet count 250,000/mm3
Erythrocyte sedimentation rate
30 mm/h
An excisional biopsy of a cervical lymph node reveals the presence of Reed-Sternberg (RS) cells. Computed tomography (CT) scans and positron emission tomography (PET) scans reveal no mediastinal mass or signs of additional disease. Which of the following aspects most strongly indicates a good prognosis for this patient?

Question: Which of the following aspects most strongly indicates a good prognosis for this patient?

Answer: Stage of the disease


Context: A 66-year-old gentleman presents to a new primary care physician to establish care after a recent relocation. His past medical history is significant for gout, erectile dysfunction, osteoarthritis of bilateral knees, mitral stenosis, and diabetic peripheral neuropathy. He denies any past surgeries along with the use of any tobacco, alcohol, or illicit drugs. He has no known drug allergies and cannot remember the names of the medications he is taking for his medical problems. He states that he has recently been experiencing chest pain with strenuous activities. What part of the patient's medical history must be further probed before starting him on a nitrate for chest pain?

Question: What part of the patient's medical history must be further probed before starting him on a nitrate for chest pain?

Answer: Erectile dysfunction


Context: A 30-year-old gravida 1 woman comes to the office for a prenatal visit. She is at 20 weeks gestation with no complaints. She is taking her prenatal vitamins but stopped the prescribed ferrous sulfate because it was making her constipated. Urinalysis shows trace protein. Uterine fundus is the expected size for a 20-week gestation. Just before leaving the examination room, she stops the physician and admits to eating laundry detergent. She is embarrassed and fears she is going crazy. Which of the following is the most likely diagnosis?

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

Answer: Iron deficiency anemia


Context: A 32-year-old woman presents to the emergency department with unilateral vision loss. She states it started suddenly this evening and this has never happened to her before. The patient is not followed by a primary care physician and is not currently taking any medications. She has had a few episodes of weakness or numbness in the past but states her symptoms usually resolve on their own. Her temperature is 97.6°F (36.4°C), blood pressure is 120/74 mmHg, pulse is 88/min, respirations are 12/min, and oxygen saturation is 98% on room air. Physical exam is notable for decreased sensation over the patient's dorsal aspect of her left foot. Visual exam reveals a loss of vision in the patient's left eye and she endorses pain in the eye on exam. Which of the following findings is also likely to be found in this patient?

Question: Which of the following findings is also likely to be found in this patient?

Answer: Electrical pain with neck flexion


Context: A 36-year-old woman comes to the physician because of progressively worsening painful swelling of both breasts for the past 24 hours. Three days ago, she vaginally delivered a healthy 2690-g (5-lb 15-oz) girl. The patient says that breastfeeding her newborn daughter is very painful. She reports exhaustion and moodiness. She has no history of serious illness. Medications include folic acid and a multivitamin. Her temperature is 37.4°C (99.3°F). Examination shows tenderness, firmness, and fullness of both breasts. The nipples appear cracked and the areolas are swollen bilaterally. 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: Cold compresses and analgesia


Context: A 48-year-old man comes to the emergency department because of sudden right flank pain that began 3 hours ago. He also noticed blood in his urine. Over the past two weeks, he has developed progressive lower extremity swelling and a 4-kg (9-lb) weight gain. Examination shows bilateral 2+ pitting edema of the lower extremities. Urinalysis with dipstick shows 4+ protein, positive glucose, and multiple red cell and fatty casts. Abdominal CT shows a large right kidney with abundant collateral vessels and a filling defect in the right renal vein. Which of the following is the most likely underlying cause of this patient's symptoms?

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

Answer: Loss of antithrombin III


Context: A 13-year-old girl presents to an orthopedic surgeon for evaluation of a spinal curvature that was discovered during a school screening. She has otherwise been healthy and does not take any medications. On presentation, she is found to have significant asymmetry of her back and is sent for a spine radiograph. The radiograph reveals a unilateral rib attached to the left transverse process of the C7 vertebrae. Abnormal expression of which of the following genes is most likely responsible for this finding?

Question: Abnormal expression of which of the following genes is most likely responsible for this finding?

Answer: Homeobox


Context: A 4-year-old boy is brought to a pediatrician by his parents for a consultation after his teacher complained about his inability to focus or make friends at school. They mention that the boy does not interact well with others at home, school, or daycare. On physical examination, his vital signs are stable with normal weight, height, and head circumference for his age and sex. His general examination and neurologic examination are completely normal. A recent audiological evaluation shows normal hearing, and intellectual disability has been ruled out by a clinical psychologist. Which of the following investigations is indicated as part of his diagnostic evaluation at present?

Question: Which of the following investigations is indicated as part of his diagnostic evaluation at present?

Answer: No further testing is needed


Context: A 73-year-old male presents to the the clinic with lumbar pain and symmetrical bone pain in his legs and arms. He has trouble going up to his bedroom on the second floor and getting up from a chair. Past medical history reveals that he has had acid reflux for the past 5 years that is refractory to medications (PPIs & H2 antagonists); thus, he had decided to stay away from foods which have previously given him heartburn - red meats, whole milk, salmon - and has eaten a mainly vegetarian diet. Which of the following processes is most likely decreased in this male?

Question: Which of the following processes is most likely decreased in this male?

Answer: Bone mineralization


Context: A 13-month-old boy is referred to an immunologist with recurrent otitis media, bacterial sinus infections, and pneumonia, which began several months earlier. He is healthy now, but the recurrent nature of these infections are troubling to his parents and they are hoping to find a definitive cause. 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 patient has five older siblings, but none of them had similar recurrent illnesses. Clinical pathology results suggest very low levels of serum immunoglobulin. As you discuss options for diagnosis with the patient’s family, which of the following tests should be performed next?

Question: As you discuss options for diagnosis with the patient’s family, which of the following tests should be performed next?

Answer: Flow cytometry


Context: A 58-year-old man presents with a lump on his neck. He says the mass gradually onset 2 months ago and has been progressively enlarging. He denies any pain, weight loss, fevers, chills, or night sweats. Past medical history is significant for HIV, diagnosed 5 years ago, managed on a new HAART regimen he just started. The patient is afebrile and vital signs are within normal limits. Physical examination shows a 3 cm mobile firm mass on the left lateral side of the neck immediately below the level of the thyroid cartilage. A biopsy of the mass is performed and reveals atypical mononuclear cells in a background of eosinophils, plasma cells, histiocytes, atypical T-lymphocytes, and bilobed cells (shown in image). 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: Mixed cellularity classical Hodgkin lymphoma


Context: A 42-year-old man presents to his primary care physician for preventative care. He does not have any current complaint. His father died of diabetic nephropathy. Vital signs include a temperature of 36.7°C (98.06°F), blood pressure of 150/95 mm Hg, and pulse of 90/min. His fasting blood glucose is 159 mg/dL (on 2 occasions) and HbA1c is 8.1%. The patient is started on metformin and lifestyle modifications. 3 months later, he comes for a follow-up visit. His serum blood glucose is 370 mg/dL and HbA1C is 11%. The patient currently complains of weight loss and excessive urination. Which of the following is the optimal therapy for this patient?

Question: Which of the following is the optimal therapy for this patient?

Answer: Basal-bolus insulin


Context: A 3-year-old boy is brought to the pediatrician by his parents because of excessive growth and a large tongue. His past medical-social history reveals that he is a product of non-consanguineous marriage to a 20-year-old primigravida. He was born at full term with a birth weight of 3.8 kg (8.4 lb) and length of 52 cm (20.5 in). His temperature is 37.0ºC (98.6°F), pulse is 90/min, and respirations are 22/min. Physical examination shows a mass coming out from his umbilicus and his head circumference is below average compared with children his age. On systemic examination, hepatomegaly is present. Asymptomatic hypoglycemia (36 mg/dL) is also detected, for which dextrose infusion is given. Which of the following is the most likely underlying mechanism that best explains the pathogenesis of this condition?

Question: Which of the following is the most likely underlying mechanism that best explains the pathogenesis of this condition?

Answer: Mutation in tumor suppressor gene on the short arm of chromosome 11


Context: A female neonate born to a 21-year-old G2P1 had jaundice at 8 hours of life. The neonate’s red blood cell type was  A+, while the mother’s RBC type was O+. The mother’s anti-A antibody titer was elevated. A screen for a fetomaternal bleed was negative. The direct Coombs test was weakly positive. The infant’s hemoglobin and total bilirubin were 10.6g/dL and 7 mg/dL, respectively. The erythrocyte glucose-6-phosphate was normal and the sickle cell test was negative. A peripheral blood smear showed normocytic normochromic RBCs, nucleated RBCs, and reticulocytes. What is the most likely diagnosis?

Question: What is the most likely diagnosis?

Answer: ABO incompatibility


Context: A 26-year-old G1P0 woman comes to her maternal and fetal medicine doctor at 15 weeks of gestation in order to be evaluated for fetal developmental abnormalities. Her family has a history of congenital disorders leading to difficulty walking so she was concerned about her child. Amniocentesis shows normal levels of all serum proteins and circulating factors. Despite this, the physician warns that there is a possibility that there may be a neural tube abnormality in this child even though the normal results make it less likely. If this child was born with a neural tube closure abnormality, which of the following findings would most likely be seen in the child?

Question: If this child was born with a neural tube closure abnormality, which of the following findings would most likely be seen in the child?

Answer: Tuft of hair or skin dimple on lower back


Context: A 75-year-old man comes to the physician because of a 2-week history of sharp, stabbing pain in the lower back that radiates to the back of his left leg. He also has had a loss of sensitivity around his buttocks and inner thighs as well as increased trouble urinating the last week. Two years ago, he was diagnosed with prostate cancer and was treated with radiation therapy. Neurologic examination shows reduced strength and reflexes in the left lower extremity; the right side is normal. The resting anal sphincter tone is normal but the squeeze tone is reduced. Which of the following is the most likely diagnosis?

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

Answer: Cauda equina syndrome


Context: A 4-year-old girl is brought to the physician by her mother because of fatigue and generalized weakness for 4 months. Examination shows decreased muscle tone. Her fasting serum glucose concentration is 41 mg/dL. The physician suspects a defect in one of the enzymes involved in the carnitine shuttle. Increased serum concentration of which of the following should most raise suspicion of a different diagnosis?

Question: Increased serum concentration of which of the following should most raise suspicion of a different diagnosis?

Answer: β-hydroxybutyrate


Context:
A 58-year-old man is admitted to the hospital for severe abdominal pain and confusion. He has a history of alcohol use disorder, with several previous admissions for intoxication. Twelve hours after admission, he has worsening shortness of breath. His temperature is 38.3°C (100.9°F), pulse is 120/min, respirations are 30/min, and blood pressure is 100/60 mm Hg. Pulse oximetry on mask ventilation shows an oxygen saturation of 85%. The patient is intubated and mechanically ventilated with an FiO2 of 40%. Physical examination shows diffuse lung crackles, marked epigastric tenderness, and a periumbilical hematoma. Cardiac examination is normal with no murmurs, rubs, or gallops. There is no jugular venous distension. Arterial blood gas analysis shows:
pH 7.29
PO2 60 mm Hg
PCO2 40 mm Hg
HCO3- 15 mmol/L
An x-ray of the chest shows bilateral opacities in the lower lung fields. Which of the following is the most likely cause of this patient's respiratory symptoms?"

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

Answer: Acute respiratory distress syndrome


Context: A 70-year-old man with a history of poorly controlled congestive heart failure comes to the physician for a follow-up examination. At his previous visit 4 months ago, a new drug was added to his treatment regimen. He reports that his dyspnea and peripheral edema have improved. His pulse is 70/min and blood pressure is 110/80 mm Hg. Physical examination shows bilateral, mildly tender enlargement of breast tissue. This patient's physical examination finding is most likely caused by a drug that acts at which of the following sites in the kidney?

Question: This patient's physical examination finding is most likely caused by a drug that acts at which of the following sites in the kidney?

Answer: Cortical collecting duct


Context: A 17-year-old white female with a history of depression is brought to your office by her parents because they are concerned that she is acting differently. She is quiet and denies any changes in her personality or drug use. After the parents step out so that you can speak alone, she begins crying. She states that school has been very difficult and has been very depressed for the past 2 months. She feels a lot of pressure from her parents and coaches and says she cannot handle it anymore. She says that she has been cutting her wrists for the past week and is planning to commit suicide. She instantly regrets telling you and begs you not to tell her parents. What is the most appropriate course of action?

Question: What is the most appropriate course of action?

Answer: Explain to her that she will have to be hospitalized as she is an acute threat to herself


Context:
A 62-year-old man presents to his primary care physician. He was brought in by his daughter as he has refused to see a physician for the past 10 years. The patient has been having worsening abdominal pain. He claims that it was mild initially but has gotten worse over the past week. The patient has been eating lots of vegetables recently to help with his pain. The patient has a past medical history of constipation and a 50 pack-year smoking history. He is not currently taking any medications. On review of systems, the patient endorses trouble defecating and blood that coats his stool. His temperature is 99.5°F (37.5°C), blood pressure is 197/128 mmHg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. On abdominal exam, the patient complains of right upper quadrant tenderness and a palpable liver edge that extends 4 cm beneath the costal margin. The patient states that he feels pain when pressure is applied and then suddenly released to the right upper quadrant. The patient's skin has a yellow hue to it. HEENT exam is notable for poor dentition, normal sclera, and normal extraocular movements. There are no palpable lymph nodes. Laboratory studies are ordered as seen below.

Hemoglobin: 9 g/dL
Hematocrit: 30%
Leukocyte count: 7,500/mm^3 with normal differential
Platelet count: 199,000/mm^3

Serum:
Na+: 140 mEq/L
Cl-: 101 mEq/L
K+: 4.0 mEq/L
HCO3-: 23 mEq/L
BUN: 29 mg/dL
Glucose: 197 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Total bilirubin: 1.1 mg/dL
AST: 150 U/L
ALT: 112 U/L

Which of the following is the most likely diagnosis?

Question:
Hemoglobin: 9 g/dL
Hematocrit: 30%
Leukocyte count: 7,500/mm^3 with normal differential
Platelet count: 199,000/mm^3

Serum:
Na+: 140 mEq/L
Cl-: 101 mEq/L
K+: 4.0 mEq/L
HCO3-: 23 mEq/L
BUN: 29 mg/dL
Glucose: 197 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Total bilirubin: 1.1 mg/dL
AST: 150 U/L
ALT: 112 U/L

Which of the following is the most likely diagnosis?

Answer: Colon cancer


Context: A 66-year-old man comes to the physician for a 3-month history of fatigue. He has hypertension and hyperlipidemia. He had a transient ischemic attack 3 years ago. He drinks 3 beers a day, and sometimes a couple more on social occasions. He currently takes aspirin, simvastatin, hydrochlorothiazide, and metoprolol. His temperature is 37.1°C (98.8°F), pulse is 78, respirations are 19/min, and oxygen saturation on room air is 97%. He is in no distress but shows marked pallor and has multiple pinpoint, red, nonblanching spots on his extremities. On palpation, his spleen is significantly enlarged. Laboratory studies show a hemoglobin of 8.0 g/dL, a leukocyte count of 80,000/mm3, and a platelet count of 34,000/mm3. A blood smear shows immature cells with large, prominent nucleoli and pink, elongated, needle-shaped cytoplasmic inclusions. Which of the following is the most likely diagnosis?

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

Answer: Acute myelogenous leukemia


Context: A 45-year-old man is brought to the emergency department after a car accident with pain in the middle of his chest and some shortness of breath. He has sustained injuries to his right arm and leg. He did not lose consciousness. His temperature is 37°C (98.6°F), pulse is 110/min, respirations are 18/min, and blood pressure is 90/60 mm Hg. He is alert and oriented to person, place, and time. Examination shows several injuries to the upper extremities and chest. There are jugular venous pulsations 10 cm above the sternal angle. Heart sounds are faint on cardiac examination. The lungs are clear to auscultation. An 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: Transthoracic echocardiography


Context: An 8-year-old boy is brought to the emergency department 3 hours after having a 2-minute episode of violent, jerky movements of his right arm at school. He was sweating profusely during the episode and did not lose consciousness. He remembers having felt a chill down his spine before the episode. Following the episode, he experienced weakness in the right arm and was not able to lift it above his head for 2 hours. Three weeks ago, he had a sore throat that resolved with over-the-counter medication. He was born at term and his mother remembers him having an episode of jerky movements when he had a high-grade fever as a toddler. There is no family history of serious illness, although his father passed away in a motor vehicle accident approximately 1 year ago. His temperature is 37°C (98.6°F), pulse is 98/min, and blood pressure is 94/54 mm Hg. Physical and neurologic examinations show no abnormalities. A complete blood count and serum concentrations of glucose, electrolytes, calcium, and creatinine are within the reference range. Which of the following is the most likely diagnosis?

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

Answer: Focal seizure


Context: An investigator is conducting a study to identify potential risk factors for post-transplant hypertension. The investigator selects post-transplant patients with hypertension and gathers detailed information regarding their age, gender, preoperative blood pressure readings, and current medications. The results of the study reveal that some of the patients had been treated with cyclosporine. This study is best described as which of the following?

Question: This study is best described as which of the following?

Answer: Case series


Context: A 56-year-old man presents to the emergency room with severe substernal chest pain associated with a 2-hour history of breathlessness and sweating. An electrocardiogram shows an ST-segment elevation myocardial infarction. Cardiac enzyme levels confirm a diagnosis of acute myocardial infarction. The patient is rushed to the catheter lab for angioplasty with stenting. The patient complains of recurrent chest pain in the ICU 56 hours post-angioplasty. Which of the following enzymes facilitates the patient’s diagnosis based on his current symptoms?

Question: Which of the following enzymes facilitates the patient’s diagnosis based on his current symptoms?

Answer: Creatine kinase (CK)-MB


Context: A 3-week-old male newborn is brought to the physician because his mother has noticed that he tires easily and sweats while feeding. During the past week, she has noticed that his lips and nails turn blue while crying. He was born at 35 weeks' gestation and weighed 2100 g (4 lb 10 oz); he currently weighs 2300 g (5 lb 1 oz). His temperature is 37.3°C (99.1°F), pulse is 168/min, respirations are 63/min, and blood pressure is 72/42 mm Hg. Examination shows a 3/6 systolic ejection murmur heard over the left upper sternal border. A single S2 is present. An echocardiography confirms the diagnosis. Which of the following factors is most responsible for this patient's cyanosis?

Question: Which of the following factors is most responsible for this patient's cyanosis?

Answer: Degree of right ventricular outflow obstruction


Context: A 13-year-old boy presents to his pediatrician with a 1-day history of frothy brown urine. He says that he believes he had strep throat some weeks ago, but he was not treated with antibiotics as his parents were worried about him experiencing harmful side effects. His blood pressure is 148/96 mm Hg, heart rate is 84/min, and respiratory rate is 15/min. Laboratory analysis is notable for elevated serum creatinine, hematuria with RBC casts, and elevated urine protein without frank proteinuria. His antistreptolysin O titer is elevated, and he is subsequently diagnosed with post-streptococcal glomerulonephritis (PSGN). His mother is distraught regarding the diagnosis and is wondering if this could have been prevented if he had received antibiotics. Which of the following is the most appropriate response?

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

Answer: Once a patient is infected with a nephritogenic strain of group A streptococcus, the development of PSGN cannot be prevented.


Context:
A 4-year-old boy is brought to the physician because of yellowish discoloration of his eyes and skin for 5 days. He has had generalized fatigue and mild shortness of breath over the past 2 months. Two weeks ago, he was treated for a urinary tract infection with antibiotics. His father has a history of undergoing a splenectomy in his childhood. Examination shows pale conjunctivae and jaundice. The abdomen is soft and nontender; the spleen is palpated 4 to 5 cm below the left costal margin. Laboratory studies show:
Hemoglobin 9.9 g/dL
Mean corpuscular volume 88 μm3
Mean corpuscular hemoglobin 31.7 pg/cell
Mean corpuscular hemoglobin concentration 37.0% Hb/cell
Leukocyte count 6600/mm3
Platelet count 233,000/mm3
Red cell distribution width 24.3% (N = 13–15)
Serum
Bilirubin
Total 12.3 mg/dL
Direct 1.8 mg/dL
Lactate dehydrogenase 401 U/L
Which of the following is the most likely cause of these findings?"

Question:
Laboratory studies show:
Hemoglobin 9.9 g/dL
Mean corpuscular volume 88 μm3
Mean corpuscular hemoglobin 31.7 pg/cell
Mean corpuscular hemoglobin concentration 37.0% Hb/cell
Leukocyte count 6600/mm3
Platelet count 233,000/mm3
Red cell distribution width 24.3% (N = 13–15)
Serum
Bilirubin
Total 12.3 mg/dL
Direct 1.8 mg/dL
Lactate dehydrogenase 401 U/L
Which of the following is the most likely cause of these findings?"

Answer: Defective spectrin in the RBC membrane


Context: A 35-year-old man is transferred to the intensive care unit after a motorcycle accident. He does not open his eyes with painful stimuli. He makes no sounds. He assumes decerebrate posture with sternal rub. His right eye is abnormally positioned downward and outward and has a dilated pupil which is not responsive to light. In contrast to this patient's findings, one would expect a patient with a diabetic mononeuropathy of the oculomotor nerve to present in which fashion?

Question: In contrast to this patient's findings, one would expect a patient with a diabetic mononeuropathy of the oculomotor nerve to present in which fashion?

Answer: Downward and outward gaze with ptosis and a responsive pupil


Context: A 3-year-old girl is brought to the physician for the evaluation of a 1-month history of episodes of irritability and occasional vomiting. The parents report that she has been drowsy during much of the day and has not engaged in her usual activities during this period. She was born at term and has been healthy. She is at the 60th percentile for height, 40th percentile for weight, and 90th percentile for head circumference. The patient is irritable and listless. Her vital signs are within normal limits. Ophthalmic examination shows bilateral optic disc swelling. The remainder of the examination shows no abnormalities. A cranial CT scan with contrast shows enlargement of the ventricular spaces as well as a 4-cm enhancing solid mass with scattered calcifications within the 4th ventricle. Which of the following is the most likely underlying mechanism for this patient's symptoms?

Question: Which of the following is the most likely underlying mechanism for this patient's symptoms?

Answer: Cerebrospinal fluid outflow obstruction


Context: A 38-year-old man comes to the physician because of persistent sadness and difficulty concentrating for the past 6 weeks. During this period, he has also had difficulty sleeping. He adds that he has been “feeling down” most of the time since his girlfriend broke up with him 4 years ago. Since then, he has only had a few periods of time when he did not feel that way, but none of these lasted for more than a month. He reports having no problems with appetite, weight, or energy. He does not use illicit drugs or alcohol. Mental status examination shows a depressed mood and constricted affect. Which of the following is the most likely diagnosis?

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

Answer: Persistent depressive disorder


Context: A 28-year-old man comes to his general practitioner for a regular checkup. He has had trouble breathing lately with coughing, shortness of breath, and wheezing. Problems first started when he went running (outside), but he is also observing the problems when taking a light walk or resting. As a child, he suffered from atopic dermatitis, just like his father and sister. He also has a history of hay fever. What is the most likely cause of his symptoms?

Question: What is the most likely cause of his symptoms?

Answer: Type I hypersensitivity


Context: A previously healthy 35-year-old woman is brought into the emergency department after being found unresponsive by her husband. Her husband finds an empty bottle of diazepam tablets in her pocket. She is stuporous. At the hospital, her blood pressure is 90/40 mm Hg, the pulse is 58/min, and the respirations are 6/min. The examination of the pupils shows normal size and reactivity to light. Deep tendon reflexes are 1+ bilaterally. Babinski sign is absent. All 4 extremities are hypotonic. The patient is intubated and taken to the critical care unit for mechanical ventilation and treatment. Regarding the prevention of pneumonia in this patient, which of the following strategies is most likely to achieve this goal?

Question: Regarding the prevention of pneumonia in this patient, which of the following strategies is most likely to achieve this goal?

Answer: Daily evaluation for ventilator weaning


Context:
A 65-year-old woman comes to the physician because of increased difficulty hearing. She has also had dull and progressive pain in her hip and lower back for the past 2 months that is worse with exertion. Examination of the ears shows impaired hearing on the left with whispered voice test and lateralization to the right with Weber testing. There is localized tenderness over the right hip and groin area with decreased range of motion of the hip. The remainder of the examination shows no abnormalities. Serum studies show:
Total protein 6.5 g/dL
Alkaline phosphatase 950 U/L
Calcium 9 mg/dL
Phosphorus 4 mg/dL
Which of the following is the most likely underlying mechanism of this patient's symptoms?"

Question:
Serum studies show:
Total protein 6.5 g/dL
Alkaline phosphatase 950 U/L
Calcium 9 mg/dL
Phosphorus 4 mg/dL
Which of the following is the most likely underlying mechanism of this patient's symptoms?"

Answer: Increased rate of bone remodeling


Context: A 24-year-old woman calls her gynecologist complaining of vaginal odor and vaginal discharge. She had an intrauterine device placed last year and does not use condoms with her boyfriend. She has a past medical history of constipation and depression. She recently was successfully treated for a urinary tract infection with a 2-day course of antibiotics. Physical exam demonstrates an off-white vaginal discharge and a strong odor. Pelvic exam demonstrates an absence of cervical motion tenderness and no adnexal tenderness. Which of the following is the most likely diagnosis?

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

Answer: Anaerobic bacteria overgrowth within the vagina


Context: A 57-year-old man presents to his primary care provider because of chest pain for the past 3 weeks. The chest pain occurs after climbing more than 2 flight of stairs or walking for more than 10 minutes and resolves with rest. He is obese, has a history of type 2 diabetes mellitus, and has smoked 15-20 cigarettes a day for the past 25 years. His father died from a myocardial infarction at 52 years of age. Vital signs reveal a temperature of 36.7 °C (98.06°F), a blood pressure of 145/93 mm Hg, and a heart rate of 85/min. The physical examination is unremarkable. Which of the following best represents the most likely etiology of the patient’s condition?

Question: Which of the following best represents the most likely etiology of the patient’s condition?

Answer: Fixed, atherosclerotic coronary stenosis (> 70%)


Context: A 40-year-old man is brought to the emergency department after sustaining multiple lacerations during a bar fight. The patient’s wife says that he has been showing worsening aggression and has been involved in a lot of arguments and fights for the past 2 years. The patient has no significant past medical or psychiatric history and currently takes no medications. The patient cannot provide any relevant family history since he was adopted as an infant. His vitals are within normal limits. On physical examination, the patient looks apathetic and grimaces repeatedly. Suddenly, his arms start to swing by his side in an uncontrolled manner. Which area of the brain is most likely affected in this patient?

Question: Which area of the brain is most likely affected in this patient?

Answer: Caudate nucleus


Context:
A 9-year-old girl is brought to the physician by her mother because of a 3-day history of face and foot swelling, dark urine, and a rash on her hands and feet. The mother reports that her daughter has had a low-grade fever, shortness of breath, and a dry cough for the past 8 days. She has had generalized weakness and pain in her right knee and ankle. She has a ventricular septum defect that was diagnosed at birth. The patient appears lethargic. Her temperature is 38.4 (101.1°F), pulse is 130/min, respirations are 34/min, and blood pressure is 110/60 mm Hg. Examination shows small, non-blanching, purple lesions on her palms, soles, and under her fingernails. There is edema of the eyelids and feet. Funduscopic examination shows retinal hemorrhages. Holosystolic and early diastolic murmurs are heard. Laboratory studies show:
Hemoglobin 11.3 g/dL
Erythrocyte sedimentation rate 61 mm/h
Leukocyte count 15,000/mm3
Platelet count 326,000/mm3
Urine
Blood 4+
Glucose negative
Protein 1+
Ketones negative
Transthoracic echocardiography shows a small outlet ventricular septum defect and a mild right ventricular enlargement. There are no wall motion abnormalities, valvular heart disease, or deficits in the pump function of the heart. Blood cultures grow Streptococcus pyogenes. Which of the following is the most likely diagnosis?"

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

Answer: Infective endocarditis


Context: A 36 year-old woman presents to the doctor’s office for evaluation of substernal chest pain and a metallic taste in her mouth. The patient has a history of metabolic syndrome and hypothyroidism. She takes levothyroxine daily. The patient’s vital signs are currently stable. On examination, she appears to be in mild discomfort, but is alert and oriented. The abdomen is mildly tender to palpation without guarding. Which of the following is the most appropriate treatment choice based on her history and physical examination?

Question: Which of the following is the most appropriate treatment choice based on her history and physical examination?

Answer: Omeprazole


Context: A 27-year-old woman presents with painful urination and malodorous urethral discharge. She states she has a single sexual partner and uses condoms for contraception. The patient's blood pressure is 115/80 mm Hg, the heart rate is 73/min, the respiratory rate is 14/min, and the temperature is 36.6℃ (97.9℉). Physical examination shows swelling and redness of the external urethral ostium. There is a yellowish, purulent discharge with an unpleasant odor. The swab culture grows N. gonorrhoeae. The doctor explains the diagnosis to the patient, and they discuss the importance of notifying her partner. The patient says she doesn't want her partner to know about her diagnosis and begs the doctor to not inform the health department. She is anxious that everybody will find out that she is infected and that her partner will leave her. She promises they will use barrier contraception while she is treated. Which of the following is the most appropriate course of action?

Question: Which of the following is the most appropriate course of action?

Answer: Explain to the patient that gonorrhea is a mandatory reported disease.


Context:
A scientist is studying a protein that is present on the plasma membrane of cells. He therefore purifies the protein in a lipid bilayer and subjects it to a number of conditions. His investigations show that the protein has the following properties:

1) It is able to change ion concentrations across the membrane without addition of ATP to the solution.

2) Its activity increases linearly with substrate concentration without any saturation even at mildly supraphysiologic conditions.

3) In some states the protein leads to an ion concentration change; whereas, it has no effect in other states.

4) Changing the electrical charge across the membrane does not affect whether the protein has activity.

5) Adding a small amount of an additional substance to the solution reliably increases the protein's activity.

These findings are consistent with a protein with which of the following functions?

Question: These findings are consistent with a protein with which of the following functions?

Answer: Mediating neuronal to muscle end plate communication


Context: A 45-year-old Caucasian man is given nitroglycerin for the management of his stable angina. Nitroglycerin given for the rapid relief of acute angina would most likely be given through what route of administration?

Question: Nitroglycerin given for the rapid relief of acute angina would most likely be given through what route of administration?

Answer: Sublingual


Context: A 54-year-old patient is brought to the emergency department by ambulance with palpitations, lightheadedness, and generalized weakness. He was enjoying the long weekend with his friends at a prolonged destination bachelor’s party over the last several days. They all drank a great deal of alcohol. He can’t quite recall how much he had to drink but he did not blackout. Past medical history includes hypertension. He takes enalapril daily. His blood pressure is 110/75 mm Hg, pulse 140/min, respiratory rate 14/min, temperature 37.0°C (98.6°F). The patient appears ill and has an irregular pulse. An electrocardiogram is performed (see in the picture). The physician explains to the patient that he has an abnormal heartbeat and he needs to be started on anticoagulation therapy to avoid an ischemic stroke from a thrombus that may be forming in his heart. In which of the following locations is a thrombus most likely to be formed?

Question: In which of the following locations is a thrombus most likely to be formed?

Answer: Left atrial appendage


Context: A 31-year-old G3P0 is admitted to the hospital with profuse vaginal bleeding and abdominal pain at 34 weeks gestation. She reports passing bright blood with clots and no water in the discharge. She denies recent trauma or medical illnesses. She had no prenatal care. Her previous pregnancies culminated in spontaneous abortions in the second trimester. She has a 6-year history of drug abuse and cocaine smoking 2 hours prior to the onset of her symptoms. Her blood pressure is 160/90 mm Hg, the heart rate is 93/min, the respiratory rate is 19/min, and the temperature is 36.9℃ (98.4℉). The fetal heart rate is 110/min. On examination, the patient is lethargic. Her pupils are constricted, but reactive to light bilaterally. There are no signs of trauma. Abdominal palpation identifies lower abdominal tenderness and strong uterine contractions. The fundus of the uterus is between the xiphoid process and umbilicus. The patient’s perineum is grossly bloody. On pelvic examination, the vaginal canal is without lesions. The cervix is almost completely effaced and 2 cm dilated. Which of the following options is the most likely cause of the patient’s pregnancy-related condition?

Question: Which of the following options is the most likely cause of the patient’s pregnancy-related condition?

Answer: Abrupt constriction of maternal and placental vessels


Context: A 61-year-old woman presents to a surgical oncologist for consideration of surgical removal of biopsy-confirmed breast cancer. The mass is located in the tail of Spence along the superolateral aspect of the left breast extending into the axilla. The surgical oncologist determines that the optimal treatment for this patient involves radical mastectomy including removal of the axillary lymph nodes. The patient undergoes all appropriate preoperative tests and is cleared for surgery. During the operation, multiple enlarged axillary lymph nodes are present along the superolateral chest wall. While exposing the lymph nodes, the surgeon accidentally nicks a nerve. Which of the following physical examination findings will most likely be seen in this patient following the operation?

Question: Which of the following physical examination findings will most likely be seen in this patient following the operation?

Answer: Scapular protrusion while pressing against a wall


Context: A 25-year-old woman presents with slightly yellow discoloration of her skin and eyes. She says she has had multiple episodes with similar symptoms before. She denies any recent history of nausea, fatigue, fever, or change in bowel/bladder habits. No significant past medical history. The patient is afebrile and vital signs are within normal limits. On physical examination, She is jaundiced, and her sclera is icteric. Laboratory findings are significant only for a mild unconjugated hyperbilirubinemia. The remainder of laboratory results is unremarkable. 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: Gilbert syndrome


Context: A 55-year-old African American female presents to her breast surgeon for a six-month follow-up visit after undergoing a modified radical mastectomy for invasive ductal carcinoma of the left breast. She reports that she feels well and her pain has been well controlled with ibuprofen. However, she is frustrated that her incisional scar is much larger than she expected. She denies any pain or pruritus associated with the scar. Her past medical history is notable for systemic lupus erythematosus and multiple dermatofibromas on her lower extremities. She has had no other surgeries. She currently takes hydroxychloroquine. On examination, a raised hyperpigmented rubbery scar is noted at the inferior border of the left breast. It appears to have extended beyond the boundaries of the initial incision. Left arm range of motion is limited due to pain at the incisional site. Abnormal deposition of which of the following molecules is most likely responsible for the appearance of this patient’s scar?

Question: Abnormal deposition of which of the following molecules is most likely responsible for the appearance of this patient’s scar?

Answer: Type III collagen


Context: A 24-year-old woman comes to the emergency department because of lower abdominal pain for 4 hours. She has had vaginal spotting for 2 days. Menses occur at irregular 20- to 45-day intervals and last for 3 to 7 days. Her last menstrual period was 8 weeks ago. She was treated for pelvic inflammatory disease at the age of 20 years with ceftriaxone and azithromycin. She is sexually active with one male partner and uses condoms inconsistently. Her pulse is 118/min, respirations are 20/min, and blood pressure is 118/66 mm Hg. Examination shows lower abdominal tenderness. Pelvic examination shows a closed cervix and a uterus of normal size with right adnexal tenderness. Her serum β-human chorionic gonadotropin concentration is 16,000 mIU/mL (N < 5). Transvaginal ultrasonography shows a 5-cm hypoechoic lesion at the junction of the fallopian tube and uterine cavity with a 3-mm layer of myometrium surrounding it. Which of the following is the most likely diagnosis?

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

Answer: Interstitial pregnancy


Context: A healthy, 16-year-old girl is brought in by her mother for a wellness visit. During the appointment, the patient’s mother brings up concerns about her daughter’s acne. The patient has had acne for 2 years. She washes her face twice a day with benzoyl peroxide and has been on doxycycline for 2 months with only mild improvement. The patient does not feel that the acne is related to her menstrual cycles. The patient’s mother states she does well in school and is the captain of the junior varsity cross-country team. She is worried that the acne is starting to affect her daughter’s self-esteem. The patient states that prom is coming up, and she is considering not going because she hates taking pictures. Upon physical exam, there are multiple open and closed comedones and scattered, red nodules on the patient’s face with evidence of scarring. The patient’s mother says her neighbor’s son tried isotretinoin and wants to know if that may work for her daughter. While talking about the risk factors for isotretinoin, you mention that patient will need to be on 2 forms of birth control. The mother asks, “Is that really necessary? We are a very religious family and my daughter knows our household rule about no sex before marriage.” Which of the following is the next step in management?

Question: We are a very religious family and my daughter knows our household rule about no sex before marriage.” Which of the following is the next step in management?

Answer: Ask the mother to leave the room before talking to the patient about her sexual activity


Context: A 20-year-old medical student presents to the clinic with a very painful lesion on her lower lip, as shown in the photograph below. She admits that she applied polymyxin ointment to the lesion without improvement. A few months ago, she used the same antibiotic ointment to treat an infected cut on her arm. At that time, she had read in her microbiology book that polymyxin is an antibiotic that disrupts cell membranes. Why did the treatment fail this time?

Question: Why did the treatment fail this time?

Answer: Organism has no cell membrane


Context: A 47-year-old male presents to a psychiatrist for the first time, explaining that he is tired of living his 'double life.' At church, he preaches vehemently against the sin of drinking alcohol, but at home he gets drunk every night. Which of the following ego defenses best explains his behavior?

Question: Which of the following ego defenses best explains his behavior?

Answer: Reaction formation


Context: A 23-year-old man is admitted to the hospital for observation because of a headache, dizziness, and nausea that started earlier in the day while he was working. He moves supplies for a refrigeration company and was handling a barrel of carbon tetrachloride before the symptoms began. He was not wearing a mask. One day after admission, he develops a fever and is confused. His temperature is 38.4°C (101.1°F). Serum studies show a creatinine concentration of 2.0 mg/dL and alanine aminotransferase concentration of 96 U/L. This patient's laboratory abnormalities are most likely due to which of the following processes?

Question: This patient's laboratory abnormalities are most likely due to which of the following processes?

Answer: Lipid peroxidation


Context: A 20-year-old college student presents to the emergency room complaining of insomnia for the past 48 hours. He explains that although his body feels tired, he is "full of energy and focus" after taking a certain drug an hour ago. He now wants to sleep because he is having hallucinations. His vital signs are T 100.0 F, HR 110 bpm, and BP of 150/120 mmHg. The patient states that he was recently diagnosed with "inattentiveness." Which of the following is the mechanism of action of the most likely drug causing the intoxication?

Question: Which of the following is the mechanism of action of the most likely drug causing the intoxication?

Answer: Increases presynaptic dopamine and norepinephrine releases from vesicles


Context: You submit a paper to a prestigious journal about the effects of coffee consumption on mesothelioma risk. The first reviewer lauds your clinical and scientific acumen, but expresses concern that your study does not have adequate statistical power. Statistical power refers to which of the following?

Question: Statistical power refers to which of the following?

Answer: The probability of detecting an association when an association does exist.


Context: A 35-year-old African American man presents with fever, abdominal pain, and severe weakness since yesterday. On physical examination, the patient is jaundiced and shows a generalized pallor. Past medical history is significant for recently receiving anti-malaria prophylaxis before visiting Nigeria. Laboratory tests show normal glucose-6-phosphate dehydrogenase (G6PD) levels. Peripheral smear shows the presence of bite cells and Heinz bodies. 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: Glucose-6-phosphate-dehydrogenase (G6PD) deficiency


Context: A 42-year-old man with hypertension and type 2 diabetes mellitus is admitted to the hospital because of swelling and redness of the left leg for 3 days. He has chills and malaise. He is treated with intravenous clindamycin for 7 days. On the 8th day at the hospital, he has profuse, foul-smelling, and watery diarrhea. He has nausea and intermittent abdominal cramping. His temperature is 38°C (100.4°F), pulse is 97/min, and blood pressure is 110/78 mm Hg. Bowel sounds are hyperactive. Abdominal examination shows mild tenderness in the left lower quadrant. Rectal examination shows no abnormalities. His hemoglobin concentration is 14.3 g/dL, leukocyte count is 12,300/mm3, and C-reactive protein concentration is 62 mg/L (N=0.08–3.1). After discontinuing clindamycin, which of the following is the most appropriate pharmacotherapy for this patient's condition?

Question: After discontinuing clindamycin, which of the following is the most appropriate pharmacotherapy for this patient's condition?

Answer: Oral fidaxomicin


Context: A 14-year-old girl is brought to the physician because of a 10-day history of vaginal bleeding. The flow is heavy with the passage of clots. Since menarche 1 year ago, menses have occurred at irregular 26- to 32-day intervals and last 3 to 6 days. Her last menstrual period was 4 weeks ago. She has no history of serious illness and takes no medications. Her temperature is 37.1°C (98.8°F), pulse is 98/min, and blood pressure is 106/70 mm Hg. Pelvic examination shows vaginal bleeding. The remainder of the examination shows no abnormalities. Her hemoglobin is 13.1 g/dL. A urine pregnancy test is negative. 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: Conjugated estrogen therapy


Context: An investigator is studying the structural integrity of collagen. Human fibroblasts are cultured on a medium and different enzymes are applied. One of the cultures is supplemented with an enzyme that inhibits the formation of hydrogen and disulfide bonds between collagen α-chains. Which of the following processes is most likely to be impaired as a result?

Question: Which of the following processes is most likely to be impaired as a result?

Answer: Bone matrix synthesis


Context: A 12-year-old African American is exposed to pollen while playing outside. The allergen stimulates TH2 cells of his immune system to secrete a factor that leads to B-cell class switching to IgE. What factor is secreted by the TH2 cell?

Question: What factor is secreted by the TH2 cell?

Answer: IL-4


Context: A 3-year-old boy is brought to the physician because of a 5-day history of yellowing of his eyes and skin. He has had generalized fatigue and mild shortness of breath over the past 2 months. Examination shows pale conjunctivae and scleral jaundice. The spleen is palpated 4 cm below the left costal margin. Laboratory studies show a hemoglobin concentration of 8.5 g/dL and a mean corpuscular volume of 76 μm3. A peripheral blood smear shows round erythrocytes that lack central pallor. Which of the following is the most likely cause of the splenomegaly seen in this child?

Question: Which of the following is the most likely cause of the splenomegaly seen in this child?

Answer: Work hypertrophy


Context: A 55-year-old woman comes to the physician because of a 4-day history of chest pain and cough with rust-colored sputum. The chest pain is sharp, stabbing, and exacerbated by coughing. Ten days ago, she had a sore throat and a runny nose. She was diagnosed with multiple sclerosis at the age of 40 years and uses a wheelchair for mobility. She has smoked a pack of cigarettes daily for the past 40 years. She does not drink alcohol. Current medications include ocrelizumab and dantrolene. Her temperature is 37.9°C (100.2°F), blood pressure is 110/60 mm Hg, and pulse is 105/min. A few scattered inspiratory crackles are heard in the right lower lung. Cardiac examination shows no abnormalities. Neurologic examination shows stiffness and decreased sensation of the lower extremities; there is diffuse hyperreflexia. An x-ray of the chest is shown. Which of the following is the most likely cause of her current symptoms?

Question: Which of the following is the most likely cause of her current symptoms?

Answer: Pulmonary embolism


Context: An 8-year-old boy is brought to the pediatrician by his parents due to recurrent episodes of wheezing for the last 2 years. He uses a salbutamol inhaler for relief from wheezing, but his symptoms have recently worsened. He often coughs during the night, which awakens him from sleep almost every other day. He is not able to play football because he starts coughing after 10–15 minutes of play. His current physical examination is completely normal and auscultation of his chest does not reveal any abnormal breath sounds. His peak expiratory flow rate (PEFR) is 75% of expected for his age, gender, and height. After a complete diagnostic evaluation, the pediatrician prescribes a low-dose inhaled fluticasone daily for at least 3 months. He also mentions that the boy may require continuing inhaled corticosteroid (ICS) therapy for a few years if symptoms recur after discontinuation of ICS. However, the parents are concerned about the side effects of corticosteroids. Which of the following corticosteroid-related adverse effects is most likely?

Question: Which of the following corticosteroid-related adverse effects is most likely?

Answer: Hoarseness of voice


Context: A 40-year-old male accountant is brought to the physician by his wife. She complains of her husband talking strangely for the past 6 months. She has taken him to multiple physicians during this time, but her husband did not comply with their treatment. She says he keeps things to himself, stays alone, and rarely spends time with her or the kids. When asked how he was doing, he responds in a clear manner with "I am fine, pine, dine doc." When further questioned about what brought him in today, he continues “nope, pope, dope doc.” Physical examination reveals no sensorimotor loss or visual field defects. Which of the following best describes the patient's condition?

Question: Which of the following best describes the patient's condition?

Answer: Patient has disorganized thinking


Context: A 62-year-old man comes to the physician because of painless swelling in his left foot for 4 months. The swelling was initially accompanied by redness, which has since resolved. He has not had fever or chills. He has a history of coronary artery disease, hyperlipidemia, and type 2 diabetes mellitus. He has had 3 sexual partners over the past year and uses condoms inconsistently. His mother had rheumatoid arthritis. Current medications include clopidogrel, aspirin, metoprolol, losartan, atorvastatin, and insulin. He is 180 cm (5 ft 11 in) tall and weighs 95 kg (209 lb); BMI is 29 kg/m2. Vital signs are within normal limits. Cardiovascular examination shows no abnormalities. Examination of the feet shows swelling of the left ankle with collapse of the midfoot arch and prominent malleoli. There is no redness or warmth. There is a small, dry ulcer on the left plantar surface of the 2nd metatarsal. Monofilament testing shows decreased sensation along both feet up to the shins bilaterally. His gait is normal. Which of the following is the most likely diagnosis?

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

Answer: Diabetic arthropathy


Context: A critical care fellow is interested in whether the auscultatory finding of pulmonary rales can accurately predict hypervolemic state. He conducts a study in 100 patients with volume overloaded state confirmed by a Swan Ganz catheter in his hospital's cardiac critical care unit. He also recruits 100 patients with euvolemic state confirmed by Swan Ganz catheter. He subsequently examines all patients in the unit for rales and finds that 80 patients in the hypervolemic group have rales in comparison to 50 patients in the euvolemic group. Which of the following is the positive predictive value of rales for the presence of hypervolemia?

Question: Which of the following is the positive predictive value of rales for the presence of hypervolemia?

Answer: 80/130


Context:
An investigator is studying the efficacy of preventative measures to reduce pesticide poisonings among Central American farmers. The investigator evaluates the effect of a ban on aldicarb, an especially neurotoxic pesticide of the carbamate class. The ban aims to reduce pesticide poisonings attributable to carbamates. The investigator followed 1,000 agricultural workers residing in Central American towns that banned aldicarb as well as 2,000 agricultural workers residing in communities that continued to use aldicarb over a period of 5 years. The results show:
Pesticide poisoning No pesticide poisoning Total
Aldicarb ban 10 990 1000
No aldicarb ban 100 1900 2000
Which of the following values corresponds to the difference in risk attributable to the ban on aldicarb?"

Question:
The results show:
Pesticide poisoning No pesticide poisoning Total
Aldicarb ban 10 990 1000
No aldicarb ban 100 1900 2000
Which of the following values corresponds to the difference in risk attributable to the ban on aldicarb?"

Answer: 0.04


Context: A 65-year-old man comes to the physician because of double vision that began this morning. He has hypertension and type 2 diabetes mellitus. He has smoked two packs of cigarettes daily for 40 years. His current medications include lisinopril, metformin, and insulin. Physical examination shows the right eye is abducted and depressed with slight intorsion. Visual acuity is 20/20 in both eyes. Extraocular movements of the left eye are normal. Serum studies show a hemoglobin A1c of 11.5%. Which of the following additional findings is most likely in this patient?

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

Answer: Upper eyelid droop on the right eye


Context:
A 55-year-old woman returns to her physician for a follow-up on the anemia that was detected last month. She received treatment for a nasopharyngeal infection 2 weeks ago. She was diagnosed with small cell lung cancer 2 years ago and was treated with combination chemotherapy. She was a 30-pack-year smoker and quit when she developed lung cancer. She has been a vegan for 2 years. The vital signs are within normal limits. Examination of the lungs, heart, abdomen, and extremities show no abnormalities. No lymphadenopathy is detected. The laboratory studies show the following:
Hemoglobin 8.5 g/dL
Mean corpuscular volume 105 μm3
Leukocyte count 4,500/mm3
Platelet count 160,000/mm3
An abdominal ultrasonography shows no organomegaly or other pathologic findings. A peripheral blood smear shows large and hypogranular platelets and neutrophils with hypo-segmented or ringed nuclei. No blasts are seen. A bone marrow aspiration shows hypercellularity. In addition, ring sideroblasts, hypogranulation, and hyposegmentation of granulocyte precursors, and megakaryocytes with disorganized nuclei are noted. Marrow myeloblasts are 4% in volume. Which of the following factors in this patient’s history most increased the risk of developing this condition?

Question: Which of the following factors in this patient’s history most increased the risk of developing this condition?

Answer: Chemotherapy


Context: A 41-year-old woman comes to the physician because of a 3-month history of anxiety, difficulty falling asleep, heat intolerance, and a 6-kg (13.2-lb) weight loss. The patient's nephew, who is studying medicine, mentioned that her symptoms might be caused by a condition that is due to somatic activating mutations of the genes for the TSH receptor. Examination shows warm, moist skin and a 2-cm, nontender, subcutaneous mass on the anterior neck. Which of the following additional findings should most raise concern for a different underlying etiology of her symptoms?

Question: Which of the following additional findings should most raise concern for a different underlying etiology of her symptoms?

Answer: Nonpitting edema


Context: A 67-year-old man presents to his primary care physician primarily complaining of a tremor. He said that his symptoms began approximately 1 month ago, when his wife noticed his right hand making "abnormal movements" while watching television. His tremor worsens when he is distracted and improves with purposeful action, such as brushing his teeth or combing his hair. He reports to having occasional headaches during times of stress. His wife notices he walks with "poor" posture and he finds himself having trouble staying asleep. He has a past medical history of migraine, generalized anxiety disorder, hypertension, and hyperlipidemia. On physical exam, the patient has a tremor that improves with extension of the arm. On gait testing, the patient has a stooped posture and takes short steps. Which of the following is the most effective treatment for this patient's symptoms?

Question: Which of the following is the most effective treatment for this patient's symptoms?

Answer: Carbidopa-levodopa


Context: Immediately after undergoing a right total knee replacement, a 69-year-old woman has severe abdominal pain, non-bloody emesis, and confusion. She has a history of Hashimoto thyroiditis that is well-controlled with levothyroxine and hyperlipidemia that is controlled by diet. She underwent bunion removal surgery from her right foot 10 years ago. Her temperature is 39°C (102.2°F), pulse is 120/min, and blood pressure is 60/30 mm Hg. Abdominal examination shows a diffusely tender abdomen with normal bowel sounds. She is confused and oriented to person but not place or time. Laboratory studies are pending. Which of the following is the most appropriate next step in the management of this patient?

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

Answer: High-dose hydrocortisone


Context: A 16-year-old presents to the primary care physician because he has noticed an increase in the size of his breast tissue over the past 3 years. He states that he is significantly taller than his entire class at school although he feels increasingly weak and uncoordinated. He performs at the bottom of his grade level academically. On physical exam the patient has marked gynecomastia with small firm testes. The physician decides to perform a karyotype on the patient. What is the most likely outcome of this test?

Question: What is the most likely outcome of this test?

Answer: 47, XXY


Context:
A 30-year-old woman comes to the physician because of increased urinary frequency over the past month. She also reports having dry mouth and feeling thirsty all the time despite drinking several liters of water per day. She has not had any weight changes and her appetite is normal. She has a history of obsessive compulsive disorder treated with citalopram. She drinks 1–2 cans of beer per day. Her vital signs are within normal limits. Physical examination shows no abnormalities. Laboratory studies show:
Serum
Na+ 130 mEq/L
Glucose 110 mg/dL
Osmolality 265 mOsmol/kg
Urine
Osmolality 230 mOsmol/kg
The patient is asked to stop drinking water for 3 hours. Following water restriction, urine osmolality is measured every hour, whereas serum osmolality is measured every 2 hours. Repeated laboratory measurements show a serum osmolality of 280 mOsmol/kg and a urine osmolality of 650 mOsmol/kg. Which of the following is the most likely diagnosis?"

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

Answer: Primary polydipsia


Context: A 43-year-old woman comes to the physician because of tingling and weakness in her left arm for the past 2 days. An image of the brachial plexus is shown. Nerve conduction study shows decreased transmission of electrical impulses in the labeled structure. Physical examination is most likely to show impairment of which of the following movements?

Question: Physical examination is most likely to show impairment of which of the following movements?

Answer: Extension of the wrist and fingers


Context:
A 13-year-old boy is brought to the emergency department with respiratory distress, fever, and a productive cough. Past medical history is significant for a history of recurrent bronchopneumonia since the age of 5, managed conservatively with antibiotics and mucolytic therapy. The patient’s weight was normal at birth, but he suffered from a failure to thrive, although there was no neonatal history of chronic diarrhea or jaundice. His current vitals are a respiratory rate of 26/min, a pulse of 96/min, a temperature of 38.8℃ (101.8°F), a blood pressure of 90/60 mm Hg, and oxygen saturation of 88% on room air. On physical examination, there is coarse crepitus bilaterally and both expiratory and inspiratory wheezing is present. The chest radiograph shows evidence of diffuse emphysema. A sweat chloride test and nitro tetrazolium test are both within normal limits. A complete blood count is significant for the following:
WBC 26300/mm3
Neutrophils 62%
Lymphocytes 36%
Eosinophils 2%
Total bilirubin 0.8 mg/dL
Direct bilirubin 0.2 mg/dL
SGOT 100 U/L
SGPT 120 U/L
ALP 200 U/L
Results of serum protein electrophoresis are shown in the figure. 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: Alpha-1 antitrypsin deficiency


Context: A 6-month-old boy is brought to the physician because of a right-sided scrotal swelling for the past 2 months. The swelling is intermittent and appears usually after the patient has been taken outdoors in a baby carrier, and disappears the next morning. The patient was born at term without complications and has been healthy. Examination shows a 3-cm, soft, nontender, and fluctuant right scrotal mass that is reducible and does not extend into the inguinal area. A light held behind the scrotum shines through. There are no bowel sounds in the mass. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate next step in the management of this patient?

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

Answer: Reassurance and follow-up


Context: A 33-year-old man is brought by ambulance to the emergency room after being a passenger in a motor vehicle accident. An empty bottle of whiskey was found in his front seat, and the patient admits to having been drinking all night. He has multiple lacerations and bruising on his face and scalp and a supportive cervical collar is placed. He is endorsing a significant headache and starts vomiting in the emergency room. His vitals, however, are stable, and he is transported to the CT scanner. While there, he states that he does not want to have a CT scan and asks to be released. What is the most appropriate course of action?

Question: What is the most appropriate course of action?

Answer: Explain to him that he is intoxicated and cannot make health care decisions, continue as planned


Context: A newborn girl is rushed to the neonatal ICU after an emergency cesarean section due to unstable vital signs after delivery. The pregnancy was complicated due to oligohydramnios and pulmonary hypoplasia. Gestation was at 38 weeks. APGAR scores were 6 and 8 at 1 and 5 minutes respectively. The newborn’s temperature is 37.0°C (98.6°F), the blood pressure is 60/40 mm Hg, the respiratory rate is 45/min, and the pulse is 140/min. Physical examination reveals irregularly contoured bilateral abdominal masses. Abdominal ultrasound reveals markedly enlarged echogenic kidneys (5 cm in the vertical dimension) with multiple cysts in the cortex and medulla. This patient is at highest risk of which of the following complications?

Question: This patient is at highest risk of which of the following complications?

Answer: Portal hypertension


Context: A 15-year-old boy presents to the emergency department for evaluation of an ‘infected leg’. The patient states that his right shin is red, swollen, hot, and very painful. The body temperature is 39.5°C (103.2°F). The patient states there is no history of trauma but states he has a history of poorly managed sickle cell anemia. A magnetic resonance imaging (MRI) scan is performed and confirms a diagnosis of osteomyelitis. Which of the following is the most likely causative agent?

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

Answer: S. aureus


Context: A 22-year-old woman comes to the physician because of 1 week of progressive left anterior knee pain. The pain is worse after sitting for a prolonged period of time and while ascending stairs. She first noticed the pain the day after a basketball game. She has often taken painful blows to the side of the knees while playing basketball but does not recall this having happened in the last game. Four weeks ago, she was diagnosed with a chlamydial urinary tract infection and treated with azithromycin. She is sexually active with one male partner; they use condoms inconsistently. Her vital signs are within normal limits. She is 178 cm (5 ft 10 in) tall and weighs 62 kg (137 lb); BMI is 19.6 kg/m2. Physical examination shows tenderness over the left anterior knee that is exacerbated with anterior pressure to the patella when the knee is fully extended; there is no erythema or swelling. Which of the following is the most likely diagnosis?

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

Answer: Patellofemoral pain syndrome


Context:
A 69-year-old male with past medical history of hypertension, hyperlipidemia, and diabetes mellitus complicated by end stage renal disease on dialysis presents to his nephrologist for a follow-up appointment. A few weeks ago, the patient saw his nephrologist because he had been feeling tired despite efforts to get enough sleep, eat a well-balanced diet, and exercise. At the time, laboratory studies revealed a hemoglobin of 9.7 g/dL, and the patient’s nephrologist suggested starting recombinant human erythropoietin (EPO). Since then, the patient has been receiving EPO intravenously three times per week. The patient reports today that he continues to feel tired despite the new treatment. His temperature is 98.0°F (36.7°C), blood pressure is 134/83 mmHg, pulse is 65/min, and respirations are 12/min. On physical exam, he has conjunctival pallor, and laboratory studies show a hemoglobin of 9.8 g/dL.

Which of the following laboratory findings would currently be seen in this patient?

Question: Which of the following laboratory findings would currently be seen in this patient?

Answer: Low MCV, increased RDW, decreased ferritin, decreased transferrin saturation


Context: A 33-year-old Caucasian female presents to her primary care provider for pruritus and shortness of breath. Over the past year, she has experienced mild progressive diffuse pruritus. She also reports that her skin seems "hard" and that it has been harder to move her fingers freely. She initially attributed her symptoms to stress at work as a commercial pilot, but when her symptoms began impacting her ability to fly, she decided to seek treatment. She has a history of major depressive disorder and takes citalopram. She smokes 1 pack per day and drinks socially. Her temperature is 98.6°F (37°C), blood pressure is 148/88 mmHg, pulse is 83/min, and respirations are 21/min. On exam, she appears anxious with increased work of breathing. Dry rales are heard at her lung bases bilaterally. Her fingers appear shiny and do not have wrinkles on the skin folds. A normal S1 and S2 are heard on cardiac auscultation. This patient's condition is most strongly associated with which of the following antibodies?

Question: This patient's condition is most strongly associated with which of the following antibodies?

Answer: Anti-DNA topoisomerase I


Context:
An investigator is studying the effects of hyperphosphatemia on calcium homeostasis. A high-dose phosphate infusion is administered intravenously to a healthy subject over the course of 3 hours. Which of the following sets of changes is most likely to occur in response to the infusion?
 $$$ Serum parathyroid hormone %%% Serum total calcium %%% Serum calcitriol %%% Urine phosphate $$$

Question: $$$ Serum parathyroid hormone %%% Serum total calcium %%% Serum calcitriol %%% Urine phosphate $$$


Context: A 35-year-old woman is brought to the emergency department for a severe, left-sided headache and neck pain that started 24 hours after she completed a half-marathon. Shortly after the headache started, she also had weakness of her right upper extremity and sudden loss of vision in her left eye, which both subsided on her way to the hospital. On arrival, she is alert and oriented to person, place, and time. Her temperature is 37.3°C (99.1°F), pulse is 77/min, respiratory rate is 20/min, and blood pressure is 160/90 mm Hg. Examination shows drooping of the left eyelid and a constricted left pupil. Visual acuity in both eyes is 20/20. There is no swelling of the optic discs. Muscle strength and deep tendon reflexes are normal bilaterally. A noncontrast CT scan of the head shows no abnormalities. Duplex ultrasonography of the neck shows absence of flow in the left internal carotid artery. 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: Heparin


Context: A 16-year-old girl is brought to the clinic by her mother for amenorrhea. The patient has never had a menstrual cycle and is worried as all her friends “have started to go through puberty.” She has been otherwise healthy with an uncomplicated birth history. “I told her not to worry since I also got my period late,” her mother reported during the encounter. Physical examination demonstrates Tanner stage 2 breasts, genital, and pubic hair. Temperature is 98.7 °F (37.1°C), blood pressure is 156/100mmHg, pulse is 92/min, and respirations are 12/min. What laboratory abnormalities would you expect to find in this patient?

Question: What laboratory abnormalities would you expect to find in this patient?

Answer: Low levels of androstenedione


Context:
A 3-week-old newborn male is brought to the physician because of increasing yellowing of his eyes and skin for 2 weeks. The mother has noticed that his stools have been paler than usual for the past week. He is exclusively formula fed, and feeds every 4 hours with a strong sucking reflux. The patient was delivered vaginally at 39 weeks' gestation to a healthy woman without any complications. Vital signs are within normal limits. He is at the 50th percentile for length and at the 65th percentile for weight. Examination shows scleral icterus and jaundice. Abdominal examination reveals a palpable liver 2 cm below the right costal margin without splenomegaly. Serum studies show:
Bilirubin
Total 17 mg/dL
Direct 13.3 mg/dL
Alkaline phosphatase 1700 U/L
AST 53 U/L
ALT 45 U/L
γ-Glutamyl transferase 174 U/L
Blood group B positive
This patient is at increased risk of developing which of the following?"

Question:
Serum studies show:
Bilirubin
Total 17 mg/dL
Direct 13.3 mg/dL
Alkaline phosphatase 1700 U/L
AST 53 U/L
ALT 45 U/L
γ-Glutamyl transferase 174 U/L
Blood group B positive
This patient is at increased risk of developing which of the following?"

Answer: Early liver cirrhosis


Context: A 33-year-old man comes into the urgent care clinic with an intensely itchy rash on the bilateral mid-lower extremities, with a fine linear demarcation approximately an inch above his socks. The rash is arranged in streaks of erythema with superimposed vesicular lesions. The patient states that he recently began hiking in the woods behind his house, but he denies any local chemical exposures to his lower extremities. His vital signs include: blood pressure of 127/76, heart rate of 82/min, and respiratory rate of 12/min. Of the following options, which is the mechanism of his reaction?

Question: Of the following options, which is the mechanism of his reaction?

Answer: Type IV–cell-mediated (delayed) hypersensitivity reaction


Context: A 23-year-old man is evaluated as a potential kidney donor for his father. His medical history is significant only for mild recurrent infections as a child. He subsequently undergoes a donor nephrectomy that is complicated by unexpected blood loss. During resuscitation, he is transfused with 4 units of O negative packed red blood cells. Shortly after the transfusion begins, he develops generalized pruritus. His temperature is 37.2°C (98.9°F), pulse is 144/min, respirations are 24/min, and blood pressure is 80/64 mm Hg. Physical examination shows expiratory wheezing in all lung fields and multiple pink, edematous wheals over the trunk and neck. His hemoglobin concentration is 8 g/dL. Serum studies show a haptoglobin concentration of 78 mg/dL (N = 30–200) and lactate dehydrogenase level of 80 U/L. This patient's underlying condition is most likely due to which of the following?

Question: This patient's underlying condition is most likely due to which of the following?

Answer: Impaired production of secretory immunoglobulins


Context: A 19-year-old man presents to the emergency department after 2 separate episodes of loss of consciousness. The first episode occurred 1 year ago while he was running in gym class. Witnesses reported clenching and shaking of both hands after he had fallen. On getting up quickly, he felt lightheaded, nauseated, and sweaty. He was given intravenous phenytoin because of concern that he may have had a seizure. His electroencephalogram was negative, and he was not started on long-term antiepileptics. One year later, a second episode of loss of consciousness occurred while playing dodgeball. He experienced a similar prodrome of lightheadedness and sweating. He has no history of seizures outside of these 2 episodes. Family history is non-contributory. He has a temperature of 37.0°C (98.6°F), a blood pressure of 110/72 mm Hg, and a pulse of 80/min. Physical examination is unremarkable. His 12-lead ECG shows normal sinus rhythm without any other abnormalities. Which of the following is the best next step in this patient?

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

Answer: Head-up tilt-table test


Context: A 24-year-old gravida 1 is admitted to the hospital after a tonic-clonic seizure at 37 weeks gestation. At the time of presentation, she complains of a severe headache, double vision, and nausea. Her vital signs are as follows: blood pressure, 165/90 mm Hg; heart rate, 91/min; respiratory rate, 9/min; and temperature, 37.0℃ (98.6℉). The rapid dipstick test performed on admission unit shows 3+ proteinuria. The fetal heart rate is 118/min. On examination, the patient is lethargic (GCS 12/15). There is 2+ pitting leg edema. The neurologic examination is significant for left eye deviation towards the nose, paralysis of the left conjugate gaze with a paralytic left eye, and right hemiplegia. Meningeal signs are negative. Which of the following findings would be expected if a head CT scan is performed?

Question: Which of the following findings would be expected if a head CT scan is performed?

Answer: Regions of hyperdensity in the left pons


Context: A 28-year-old woman is brought to the emergency department after being found in a confused state on an interstate rest area in Florida. She is unable to recall her name, address, or any other information regarding her person. She denies being the woman on a Connecticut driver's license found in her wallet. A telephone call with the police department of her hometown reveals that she had been reported missing three days ago by her husband. When the husband arrives, he reports that his wife has had a great deal of stress at work lately and before she went missing, was anxious to tell her boss that she will not meet the deadline for her current project. She has had two major depressive episodes within the past 4 years that were treated with citalopram. She drinks one to two beers daily and sometimes more on weekends. She does not use illicit drugs. Her vital signs are within normal limits. Physical and neurological examinations show no abnormalities. On mental status exam, she is oriented only to time and place but not to person. Short-term memory is intact; she does not recognize her husband or recall important events of her life. Which of the following is the most likely diagnosis?

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

Answer: Dissociative amnesia with dissociative fugue


Context: A 37-year-old woman, gravida 3, para 2, at 28 weeks' gestation comes to the physician for a follow-up examination. One week ago, an oral glucose tolerance screening test showed elevated serum glucose levels. She has complied with the recommended diet and lifestyle modifications. Over the past week, home blood glucose monitoring showed elevated fasting and post-prandial blood glucose levels. Which of the following describes the mechanism of action of the most appropriate pharmacotherapy for this patient?

Question: Which of the following describes the mechanism of action of the most appropriate pharmacotherapy for this patient?

Answer: Binding of tyrosine kinase receptors


Context: A 62-year-old woman comes to the physician for decreased vision and worsening headaches since this morning. She has hypertension and hypercholesterolemia. Pulse is 119/min and irregular. Current medications include ramipril and atorvastatin. Ocular and funduscopic examination shows no abnormalities. The findings of visual field testing are shown. 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: Occlusion of the posterior cerebral artery


Context: Several years after a teenage boy and his younger brother witnessed a gang related murder, they both decided to come forward and report it to authorities. The older brother describes the horrific decapitation of the gang member without displaying any emotion; but when the younger brother was asked about the crime, he had no recollection of the event. Which two ego defenses are being displayed by these brothers, respectively?

Question: Which two ego defenses are being displayed by these brothers, respectively?

Answer: Isolation of affect; Repression


Context: A 27-year-old man from Southern California presents with progressive chest pain, non-productive cough, and shortness of breath for the past 24 hours. He denies any similar symptoms in the past. He denies any family history of cardiac disease, recent travel, or exposure to sick contacts. His temperature is 38.5°C (101.3°F), pulse is 105/min, blood pressure is 108/78 mm Hg, and the respiratory rate is 32/min. On physical examination, patient is cachectic and ill-appearing. Bilateral pleural friction rubs are present on pulmonary auscultation. Antecubital track marks are noted bilaterally. An echocardiogram is performed and results are shown below. 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: Infective endocarditis


Context: A 4-year-old boy presents with a recent history of frequent falls. The images below depict his movements when he tries to get up from the floor. 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: Duchenne muscular dystrophy


Context: A 15-year-old adolescent is brought to the physician by her parents. She is concerned that she has not started menstruating yet. She is also self-conscious because her chest has not yet developed and all of her friends are taller and much more developed. Past medical history is noncontributory. Her mother started menstruating around the age of 13 and her older sister at the age of 12. The patient is more concerned about her poor performance in sports. She says that she can not participate in sports like before and gets tired very early. Today, her heart rate is 90/min, respiratory rate is 17/min, blood pressure is 110/65 mm Hg, and temperature of 37.0°C (98.6°F). On physical exam, her heart has a regular rate and rhythm and lungs are clear to auscultation bilaterally. On physical exam, her brachial pulses appear bounding (4+) and her femoral pulses are diminished (2+). Her legs also appear mildly atrophic with poor muscle development bilaterally. Her neck appears short with excessive skin in the lateral neck area. This patient’s symptoms are most likely associated with which of the following conditions?

Question: This patient’s symptoms are most likely associated with which of the following conditions?

Answer: Turner syndrome


Context: A 33-year-old female presents with recent onset of painful urination, fever, and right flank pain. Urinary sediment analysis is positive for the presence of white blood cell casts and Gram-negative bacteria. She has not recently started any new medications. What is the most likely diagnosis in this patient?

Question: What is the most likely diagnosis in this patient?

Answer: Pyelonephritis


Context: An 82-year-old right-handed woman is brought in by ambulance after being found down in her home. On presentation, she is found to be awake but does not follow directions or respond to questions. She is able to speak and produces a fluent string of nonsensical words and sounds. She does not appear to be bothered by her deficits. Subsequent neurologic exam finds that the patient is unable to comprehend any instructions and is also unable to repeat phrases. CT scan reveals an acute stroke to her left hemisphere. Damage to which of the following structures would be most likely to result in this pattern of deficits?

Question: Damage to which of the following structures would be most likely to result in this pattern of deficits?

Answer: Superior temporal gyrus


Context: A 6-year-old Hispanic male was admitted to the hospital for pain in his left thigh that has increased in severity over the past several months to the point that he can no longer walk. His mother explained that he had the pain about a year ago that resolved spontaneously. She also explained that he has had nose bleeds frequently for the past 6 months. On physical exam, hepatosplenomegaly was observed and he was noted to have a low-grade fever. A CT with intravenous contrast demonstrated aseptic necrosis of the left femoral head. Based on the clinical presentation, the attending physician ordered an assay showing significantly low levels of beta-glucocerebrosidase in peripheral blood leukocytes. Which of the following diseases shares a similar mode of inheritance as the disease experienced by this patient?

Question: Which of the following diseases shares a similar mode of inheritance as the disease experienced by this patient?

Answer: Phenylketonuria


Context: A 72-year-old woman comes to the physician for follow-up care. One year ago, she was diagnosed with a 3.8-cm infrarenal aortic aneurysm found incidentally on abdominal ultrasound. She has no complaints. She has hypertension, type 2 diabetes mellitus, and COPD. Current medications include hydrochlorothiazide, lisinopril, glyburide, and an albuterol inhaler. She has smoked a pack of cigarettes daily for 45 years. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 12/min, and blood pressure is 145/85 mm Hg. Examination shows a faint abdominal bruit on auscultation. Ultrasonography of the abdomen shows a 4.9-cm saccular dilation of the infrarenal aorta. 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: Elective endovascular aneurysm repair