Context: A 20-year-old girl presents to a physician following unprotected coitus with her boyfriend about 10 hours ago. She tells the doctor that although they usually use a barrier method of contraception, this time they forgot. She does not want to become pregnant. She also mentions that she has major depression and does not want to take an estrogen-containing pill. After necessary counseling, the physician prescribes an enteric-coated pill containing 1.5 mg of levonorgestrel. Which of the following is the primary mechanism of action of this drug?

Question: Which of the following is the primary mechanism of action of this drug?

Answer: Delayed ovulation through inhibition of follicular development


Context:
A 42-year-old man comes to his physician with a history of fever, non-bloody diarrhea, and headache for 10 days. He also complains of anorexia and abdominal pain. He returned from a trip to India 3 weeks ago. His temperature is 40.0°C (104.0°F), pulse is 65/min, respirations are 15/min, and blood pressure is 135/80 mm Hg. He has developed a blanchable rash on his chest and trunk. A photograph of the rash is shown. Examination of the heart, lungs, and abdomen show no abnormalities. Laboratory studies show:
Hemoglobin 15 g/dL
Mean corpuscular volume 95 μm3
White blood cell count 3400/mm3
Percent segmented neutrophils 40%
Which of the following is the most likely diagnosis?

Question:
Laboratory studies show:
Hemoglobin 15 g/dL
Mean corpuscular volume 95 μm3
White blood cell count 3400/mm3
Percent segmented neutrophils 40%
Which of the following is the most likely diagnosis?

Answer: Enteric fever


Context: An otherwise healthy 25-year-old man comes to the physician because of a 3-month history of intermittent palpitations and worsening shortness of breath on exertion. He has not had chest pain or nocturnal dyspnea. The patient is 195 cm (6 ft 5 in) tall and weighs 70 kg (154 lbs); BMI is 18.4 kg/m2. His pulse is 110/min and blood pressure is 140/60 mm Hg. The lungs are clear to auscultation. Cardiac examination is shown. Which of the following is the most likely diagnosis?

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

Answer: Aortic regurgitation


Context: A 4-year-old boy is brought to the clinic by his mother with a history of fever for the past 3 days, yellow nasal discharge, and a severe earache in the right ear. He has no prior history of ear infections and is otherwise healthy. The physician suspects that the infectious agent is Streptococcus pneumoniae and prescribes the appropriate treatment. Which of the following is true about the mechanism of antigen processing in this example?

Question: Which of the following is true about the mechanism of antigen processing in this example?

Answer: The pathway involved allows for recognition of extracellular antigens.


Context: A 39-year-old woman is brought to the emergency room by her husband because of severe dyspnea and dizziness. Her symptoms started suddenly 30 minutes ago. She appears distressed. Arterial blood gas shows a pH of 7.51, pO2 of 100 mm Hg, and a pCO2 of 30 mm Hg. Which of the following is the most likely cause?

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

Answer: Panic attack


Context: A 43-year-old man is brought to the emergency department 30 minutes after falling from the roof of a construction site. He reports abdominal and right-sided flank pain. His temperature is 37.1°C (98.8°F), pulse is 114/min, and blood pressure is 100/68 mm Hg. Physical examination shows numerous ecchymoses over the trunk and flanks and a tender right abdomen without a palpable mass. Focused assessment with sonography for trauma (FAST) shows no intraperitoneal fluid collections. His hemoglobin concentration is 7.6 g/dL. The most likely cause of his presentation is injury to which of the following organs?

Question: The most likely cause of his presentation is injury to which of the following organs?

Answer: Kidney


Context: A 34-year-old female medical professional who works for a non-governmental organization visits her primary care provider for a routine health check-up. She made a recent trip to Sub-Saharan Africa where she participated in a humanitarian medical project. Her medical history and physical examination are unremarkable. A chest radiograph and a tuberculin skin test (PPD) are ordered. The chest radiograph is performed at the side and the PPD reaction measures 12 mm after 72 hours. Which of the following mechanisms is involved in the skin test reaction?

Question: Which of the following mechanisms is involved in the skin test reaction?

Answer: Th1-mediated cytotoxicity


Context: A 2-day-old newborn male delivered at 38 weeks' gestation is evaluated for poor feeding and irritability. His temperature is 35°C (95°F), pulse is 168/min, respirations are 80/min, and blood pressure is 60/30 mm Hg. Blood culture on sheep agar grows motile, gram-positive bacteria surrounded by a narrow clear zone. Further testing confirms the presence of a pore-forming toxin. Which of the following is the most important factor in successful clearance of the causal pathogen?

Question: Which of the following is the most important factor in successful clearance of the causal pathogen?

Answer: Interferon-γ-induced macrophage activation


Context: A 25-year-old woman presents to the emergency department with sudden onset of lower limb weakness for the past 2 days. She says she also hasn’t been able to urinate for that same period. There is no history of trauma, fever, weight loss, recent respiratory tract infection, or diarrhea. She has a past medical history of left arm weakness 18 months ago that resolved spontaneously. Her father had type 2 diabetes mellitus, ischemic heart disease, and left-sided residual weakness secondary to an ischemic stroke involving the right middle cerebral artery. Her vital signs include: blood pressure 120/89 mm Hg, temperature 36.7°C (98.0°F), pulse 78/min, and respiration rate 16/min. Muscle strength is 3/5 in both lower limbs with increased tone and exaggerated deep tendon reflexes. The sensation is decreased up to the level of the umbilicus. Muscle strength, tone, and deep tendon reflexes in the upper limbs are normal. On flexion of the neck, the patient experiences electric shock-like sensations that travel down to the spine. Funduscopic examination reveals mildly swollen optic discs bilaterally. Which of the following is the next best step in management for this patient?

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

Answer: Intravenous methylprednisolone


Context: A 37-year-old man is brought to the emergency department because he was found down on a city sidewalk. Upon presentation he is found to be disheveled with multiple poorly healed wounds on his hands and feet. He has had dozens of previous presentations for alcohol intoxication and is currently known to be homeless. Physical examination reveals multiple minor wounds, alopecia, and decreased axillary hair. Upon being aroused, the patient reveals that he has had difficulty with taste and smell and has also had severe diarrhea over the last week. The deficient substance most likely responsible for this patient's symptoms is associated with which of the following proteins?

Question: The deficient substance most likely responsible for this patient's symptoms is associated with which of the following proteins?

Answer: RNA polymerase


Context:
A 31-year-old woman presents to the emergency department with a history of fever and vomiting for 2 days and severe headache for a day. Past medical history is significant for migraine diagnosed 10 years ago, but she reports that her current headache is different. She describes the pain as generalized, dull, continuous, severe in intensity, and exacerbated by head movements. Physical examination reveals a blood pressure of 110/76 mm Hg and a temperature of 39.1°C (102.4°F). The patient is awake but in great distress due to pain. A pink-purple petechial rash covers her chest and legs. Extraocular movements are normal. She complains of neck pain and asks you to turn off the lights. Muscle strength is normal in all 4 limbs. Fundoscopic examination is normal. Baseline laboratory investigations are shown:
Laboratory test
Sodium 145 mEq/L
Potassium 3.2 mEq/L
Glucose 87 mg/dL
Creatinine 1.0 mg/dL
White blood cell count 18,900/mm3
Hemoglobin 13.4 g/dL
Platelets 165,000/mm3
INR 1.1
Aerobic and anaerobic blood cultures are taken and empiric antibiotics are started. A lumbar puncture is performed. Which of the following cerebrospinal fluid (CSF) findings are expected in this patient?

Question: Which of the following cerebrospinal fluid (CSF) findings are expected in this patient?

Answer: CSF: WBC 8,500 cells/mm3, neutrophil predominant, protein 112 mg/dL, glucose 15 mg/dL


Context: A 48-year-old man is being evaluated for an acquired defect of the myeloid stem cell line with a mutation in the PIG-A gene. His diagnosis was first suspected due to anemia and recurrent pink-tinged urine. Which of the markers will be negative in the flow cytometry test for his condition?

Question: Which of the markers will be negative in the flow cytometry test for his condition?

Answer: CD55


Context: A team of epidemiologists is investigating an outbreak of hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing E. coli O104:H4. In Europe, multiple episodes of illness were reported in May 2017 within a large extended family of 16 family members, who all attended a family reunion in late April where they ate sprouts contaminated with E. coli. In the ensuing weeks, multiple family members were admitted to local hospitals for treatment of HUS. A graph depicting the course of the disease is shown. Each row represents a patient. The gray bars represent the duration of the disease. Based on the graph, which of the following is the attack rate among the individuals at risk in the month of May?

Question: Based on the graph, which of the following is the attack rate among the individuals at risk in the month of May?

Answer: 6/15


Context: A 25-year-old man is brought to the emergency department 6 hours after rescuing babies and puppies from a burning daycare center. He says that he has a severe headache, feels nauseous and dizzy. He is tachypneic. An arterial blood gas shows pH 7.3, PaCO2 49 mmHg, PaO2 80 mmHg. Serum lactate level is 6 mmol/L. What biochemical process explains these laboratory values?

Question: What biochemical process explains these laboratory values?

Answer: Low pyruvate dehydrogenase activity


Context: A 49-year-old woman with a history of hepatitis C cirrhosis complicated by esophageal varices, ascites, and hepatic encephalopathy presents with 1 week of increasing abdominal discomfort. Currently, she takes lactulose, rifaximin, furosemide, and spironolactone. On physical examination, she has mild asterixis, generalized jaundice, and a distended abdomen with positive fluid wave. Diagnostic paracentesis yields a WBC count of 1196/uL with 85% neutrophils. Which of the following is the most appropriate treatment?

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

Answer: Cefotaxime


Context: A 7-year-old girl is brought to the physician by her parents for the evaluation of pubic hair development. She has a history of a fracture in each leg and one fracture in her right arm. Her performance at school is good. There is no family history of serious illness. She takes no medications. Vital signs are within normal limits. Genital examination shows coarse, dark hair along the labia. The breast glands are enlarged and the breast bud extends beyond the areolar diameter. There are several hyperpigmented macules with rough, serpiginous borders of different sizes on the lower and upper extremities. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?

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

Answer: McCune-Albright syndrome


Context: A 63-year-old man with aortic valve disease is admitted to the hospital for a 3-week history of progressively worsening fatigue, fever, and night sweats. He does not smoke, drink alcohol, or use illicit drugs. Temperature is 38.2°C (100.8°F). Physical examination shows a systolic murmur and tender, erythematous nodules on the finger pads. Blood cultures show alpha-hemolytic, gram-positive cocci that are catalase-negative and optochin-resistant. Which of the following is the most likely causal organism?

Question: Which of the following is the most likely causal organism?

Answer: Viridans streptococci


Context: A 23-year-old woman presents to the emergency department after being found unresponsive by her friends. The patient is an IV drug user and her friends came over and found her passed out in her room. The patient presented to the emergency department 2 days ago after being involved in a bar fight where she broke her nose and had it treated and packed with gauze. Her temperature is 99.3°F (37.4°C), blood pressure is 90/48 mmHg, pulse is 150/min, respirations are 24/min, and oxygen saturation is 97% on room air. Physical exam is notable for an obtunded woman with nasal packing and EKG tags from her last hospital stay, as well as a purpuric rash on her arms and legs. Her arms have track marks on them and blisters. Which of the following is the best next step in management?

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

Answer: Removal of nasal packing


Context: A 25-year-old woman presents to her primary care physician with a chief complaint of diffuse muscle aches and pains. She states that she has trouble doing everyday tasks such as showering, cooking, and cleaning due to the pain. The patient has a past medical history of anxiety and bulimia nervosa and is currently not taking any medications. Upon further questioning, the patient states that her symptoms started last week when her boyfriend left her for another individual. The patient was quite upset, as she states she always had tended to all his needs and never argued with him. Since he has left, she has been unable to decide what she should do with herself during the day. The patient has been living with her mother for the past day and states that has helped greatly, as her mother helps her plan her days and gives her chores to do. Regardless, the patient states that her pain persists. The physician sets up a referral for the patient to work with a psychiatrist. Upon hearing this, the patient becomes visually bothered and questions if the physician is actually trying to help her. Which of the following personality disorder does this patient most likely suffer from?

Question: Which of the following personality disorder does this patient most likely suffer from?

Answer: Dependent


Context: A 22-year-old man presents with a history of lightheadedness, weakness, and palpitations when he assumes an upright position from a supine position. He is otherwise a healthy man without a history of alcohol or other substance abuse. His supine and standing blood pressures (measured at 3-minute intervals) were 124/82 mm Hg and 102/72 mm Hg, respectively. He was advised to perform a Valsalva maneuver while monitoring blood pressure and heart rate to assess the integrity of his baroreflex control. Which of the following statements is correct?

Question: Which of the following statements is correct?

Answer: During late phase II, there is an increase in both blood pressure and heart rate


Context: A tall, slender 32-year-old man comes to the emergency room because of sudden chest pain, cough, and shortness of breath. On physical examination, he has decreased breath sounds on the right. Chest radiography shows translucency on the right side of his chest. His pCO2 is elevated and pO2 is decreased. What is the most likely cause of his symptoms?

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

Answer: Spontaneous pneumothorax


Context: A 63-year-old woman presents with dyspnea on exertion. She reports that she used to work in her garden without any symptoms, but recently she started to note dyspnea and fatigue after working for 20–30 minutes. She has type 2 diabetes mellitus diagnosed 2 years ago but she does not take any medications preferring natural remedies. She also has arterial hypertension and takes torsemide 20 mg daily. The weight is 88 kg and the height is 164 cm. The vital signs include: blood pressure is 140/85 mm Hg, heart rate is 90/min, respiratory rate is 14/min, and the temperature is 36.6℃ (97.9℉). Physical examination is remarkable for increased adiposity, pitting pedal edema, and present S3. Echocardiography shows a left ventricular ejection fraction of 51%. The combination of which of the following medications would be a proper addition to the patient’s therapy?

Question: The combination of which of the following medications would be a proper addition to the patient’s therapy?

Answer: Enalapril and bisoprolol


Context: A 77-year-old woman with congestive heart failure is admitted to the hospital for evaluation prior to cardiac transplantation. During her stay at the hospital, the physician prescribes a drug to improve cardiac contractility. The drug works by selectively inhibiting an isoenzyme that is responsible for the degradation of cyclic adenosine monophosphate. Which of the following is the most likely adverse effect of this drug?

Question: Which of the following is the most likely adverse effect of this drug?

Answer: Hypotension


Context: A 24-year-old woman comes to her physician because of fatigue. She has been coming to the office multiple times a month for various minor problems over the past six months. During the appointments, she insists on a first name basis and flirts with her physician. She always dresses very fashionably. When his assistant enters the room, she tends to start fidgeting and interrupt their conversation. When the physician tells her politely that her behavior is inappropriate, she begins to cry, complaining that no one understands her and that if people only listened to her, she would not be so exhausted. She then quickly gathers herself and states that she will just have to keep looking for a physician who can help her, although she has doubts she will ever find the right physician. She does not have a history of self harm or suicidal ideation. Which of the following is the most likely diagnosis?

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

Answer: Histrionic personality disorder


Context: A 59-year-old man comes to the physician for evaluation of progressively worsening back pain that began about 2 months ago. It started as a dull pain that has now developed into a constant throbbing pain that makes falling asleep difficult. Ibuprofen and acetaminophen do not provide relief. The patient has not had any bowel incontinence, limb weakness, or paresthesias. He has metastatic prostate cancer with known metastasis to the sacrum and left ilium, but has had minimal pain related to these sites. He underwent bilateral orchiectomy two years ago, complicated by urinary incontinence. He currently takes no medications. Vital signs are within normal limits. There is midline tenderness to palpation over the lower lumbar spine. MRI scan of the spine shows a new sclerotic lesion at the L5 vertebral body. 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: Local radiation


Context:
A 62-year-old man comes to the physician because of fatigue and swelling of the lower legs for 3 weeks. One year ago, he had an 85% stenosis in the left anterior descending artery, for which he received 2 stents. He was diagnosed with hepatitis C 5 years ago. He has type 2 diabetes mellitus and arterial hypertension. Current medications include aspirin, metformin, and ramipril. He does not smoke or drink alcohol. His temperature is 37°C (98.6°F), pulse is 92/min, and blood pressure is 142/95 mm Hg. Examination shows 2+ pretibial edema bilaterally. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 10.2 g/dL
Leukocyte count 6500/mm3
Platelet count 188,000/mm3
Serum
Na+ 137 mEq/L
Cl− 105 mEq/L
K+ 5.2 mEq/L
Urea nitrogen 60 mg/dL
Glucose 110 mg/dL
Creatinine 3.9 mg/dL
Albumin 3.6 mg/dL
HbA1C 6.8%
Urine
Blood negative
Glucose 1+
Protein 3+
WBC 0–1/hpf
A renal biopsy shows sclerosis in the capillary tufts and arterial hyalinosis. Which of the following is the most likely underlying mechanism of this patient's findings?"

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

Answer: Arterial hypertension


Context: A 17-year-old girl comes to the physician because of a 1-week history of severe itching in the area of her genitals. She reports that the itching is most severe at night. She has been sexually active with three partners over the past year; she uses condoms for contraception. Her current sexual partner is experiencing similar symptoms. Pelvic examination shows vulvar excoriations. A photomicrograph of an epilated pubic hair is shown. Which of the following is the most likely causal organism?

Question: Which of the following is the most likely causal organism?

Answer: Phthirus pubis


Context: An 15-year-old boy is brought to the emergency department after he passed out in the hallway. On presentation, he is alert but confused about why he is in the hospital. He says that he remembers seeing flashes of light to his right while walking out of class but cannot recall what happened next. His next memory is being woken up by emergency responders who wheeled him into an ambulance. A friend who was with him at the time says that he seemed to be swallowing repeatedly and staring out into space. He has never had an episode like this before, and his past medical history is unremarkable. Which of the following characteristics is most likely true of the cause of this patient's symptoms?

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

Answer: Starts in the left occipital lobe and then generalizes


Context:
A clinical study is performed to examine the effect of smoking on the development of pulmonary hypertension (PAH) in a sample of 40-year-old women. A group of 1,000 matched healthy subjects (500 controls; 500 smokers) were monitored for the development of (PAH) from enrollment to death. The data from the study are shown in the table below:
Group\PAH Yes No
Smokers 35 465
Controls 20 480
Which of the following is correct regarding the risk of developing PAH from this study?

Question:
The data from the study are shown in the table below:
Group\PAH Yes No
Smokers 35 465
Controls 20 480
Which of the following is correct regarding the risk of developing PAH from this study?

Answer: The lifetime absolute risk increase of developing PAH in female smokers is 3%.


Context: A 41-year-old man with a history of hypertension and hyperlipidemia is brought to the emergency department by his wife for difficulty breathing after choking on food at dinner. He is unconscious and pulseless on arrival. Despite appropriate life-saving measures, he dies. Examination of the heart shows a necrotic, pale yellow plaque in the left circumflex artery. Similar lesions are most likely to be found in which of the following locations?

Question: Similar lesions are most likely to be found in which of the following locations?

Answer: Abdominal aorta


Context: A 6-month-old girl is brought to the emergency department by her father after he observed jerking movements of her arms and legs earlier in the day. She appears lethargic. Physical examination shows generalized hypotonia. The liver edge is palpable 3 cm below the right costophrenic angle. Her fingerstick glucose shows hypoglycemia. Serum levels of acetone, acetoacetate, and β-hydroxybutyrate are undetectable. Molecular genetic testing shows a mutation in the carnitine palmitoyltransferase II gene. This patient will most likely benefit from supplementation with which of the following?

Question: This patient will most likely benefit from supplementation with which of the following?

Answer: Medium-chain triglycerides


Context: A 45-year-old male reports several years of asbestos exposure while working in the construction industry. He reports smoking 2 packs of cigarettes per day for over 20 years. Smoking and asbestos exposure increase the incidence of which of the following diseases?

Question: Smoking and asbestos exposure increase the incidence of which of the following diseases?

Answer: Bronchogenic carcinoma


Context: A 19-year-old woman presents for a sports physical. She says he feels healthy and has no concerns. Past medical history is significant for depression and seasonal allergies. Current medications are fluoxetine and oral estrogen/progesterone contraceptive pills. Family history is significant for a sister with polycystic ovarian syndrome (PCOS). The patient denies current or past use of alcohol, recreational drugs, or smoking. She reports that she has been on oral birth control pills since age 14 and uses condoms inconsistently. No history of STDs. She is sexually active with her current boyfriend, who was treated for chlamydia 2 years ago. She received and completed the HPV vaccination series starting at age 11. Her vital signs include: temperature 36.8°C (98.2°F), pulse 97/min, respiratory rate 16/min, blood pressure 120/75 mm Hg. Physical examination is unremarkable. Which of the following are the recommended guidelines for cervical cancer screening for this patient at this time?

Question: Which of the following are the recommended guidelines for cervical cancer screening for this patient at this time?

Answer: No cervical cancer screening is indicated at this time


Context: A 47-year-old man comes to the physician for a routine health maintenance examination. He has no complaints and has no history of serious illness. He works as a forklift operator in a factory. His brother died of malignant melanoma. He smokes occasionally and drinks a glass of wine once a week. His pulse is 79/min and blood pressure is 129/84 mm Hg. Which of the following causes of death is this patient most at risk for over the next 15 years?

Question: Which of the following causes of death is this patient most at risk for over the next 15 years?

Answer: Coronary artery disease


Context: A 3-year-old boy is brought to the emergency department after losing consciousness. His parents report that he collapsed and then had repetitive, twitching movements of the right side of his body that lasted approximately one minute. He recently started to walk with support. He speaks in bisyllables and has a vocabulary of almost 50 words. Examination shows a large purple-colored patch over the left cheek. One week later, he dies. Which of the following is the most likely finding on autopsy of the brain?

Question: Which of the following is the most likely finding on autopsy of the brain?

Answer: Leptomeningeal vascular malformation


Context:
A 7-year-old girl is brought to the pediatrician by her parents for red papules over her left thigh and swelling in the right axilla for the past few days. Her parents say that she had a cat bite on her left thigh 2 weeks ago. Her temperature is 38.6°C (101.4°F), pulse is 90/min, and respirations are 22/min. On her physical examination, hepatosplenomegaly is present with a healing area of erythema on her left hand. Her laboratory studies show:
Hemoglobin 12.9 gm/dL
Leukocyte count 9,300/mm3
Platelet count 167,000/mm3
ESR 12 mm/hr
Which of the following is the most appropriate next step in management?

Question:
Her laboratory studies show:
Hemoglobin 12.9 gm/dL
Leukocyte count 9,300/mm3
Platelet count 167,000/mm3
ESR 12 mm/hr
Which of the following is the most appropriate next step in management?

Answer: Rifampin + azithromycin


Context: A 5-month-old girl is brought to the physician because of a red lesion on her scalp that was first noticed 2 months ago. The lesion has been slowly increasing in size. It is not associated with pain or pruritus. She was born at 37 weeks' gestation after an uncomplicated pregnancy and delivery. Her older sister is currently undergoing treatment for a fungal infection of her feet. Examination shows a solitary, soft lesion on the vertex of the scalp that blanches with pressure. A photograph of the lesion 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:
Reassurance and follow-up
"


Context: A 19-year-old female complains of abnormal facial hair growth. This has been very stressful for her, especially in the setting of not being happy with her weight. Upon further questioning you learn she has a history of type 2 diabetes mellitus. Her height is 61 inches, and weight is 185 pounds (84 kg). Physical examination is notable for facial hair above her superior lip and velvety, greyish thickened hyperpigmented skin in the posterior neck. Patient is started on a hormonal oral contraceptive. Which of the following is a property of the endometrial protective hormone found in this oral contraceptive?

Question: Which of the following is a property of the endometrial protective hormone found in this oral contraceptive?

Answer: Thickens cervical mucus


Context:
A 63-year-old woman presents to her physician with intractable bone pain, poor appetite, and hiccups. She says symptoms began 3 months ago and have progressively worsened. She also complains of chest pain, generalized pruritus, and dryness of her skin. Past medical history is significant for frequent fractures, poorly controlled hypertension, and type 2 diabetes mellitus refractory to conventional therapy. On physical examination, there is marked conjunctival pallor, prominent zygomatic bones, grade 3 asterixis, and a grayish-brown slate over her skin. On cardiac auscultation, a loud pericardial friction rub is noted at the lower left sternal border. Laboratory findings are shown below:
Laboratory results
Sodium 146 mEq/L
Chloride  104 mEq/L
BUN 22 mg/dL
Calcium 9.2 mg/dL
Uric acid  3.4 mg/dL
Potassium  5.2 mEq/L
Bicarbonate  16 mmol/L
Creatinine  2.1mg/dL
Magnesium 1.1 mEq/L
Hemoglobin  8.6 g/dL
A peripheral blood smear shows normocytic normochromic anemia. A radiograph of the lumbar spine shows multiple well defined cystic lesions with areas of subperiosteal thinning. Which of the following is the most likely underlying cause of the radiographic findings in this patient?

Question: Which of the following is the most likely underlying cause of the radiographic findings in this patient?

Answer: Hormone-mediated fibrous replacement of bone


Context:
A 38-year-old woman comes to the physician because of frequent headaches and blurring of vision. She also complains of weight gain, menstrual irregularities, and excessive growth of body hair. She says that, for the first time since she turned 18, her shoe and ring sizes have increased, and also complains that her voice has become hoarser. She does not smoke or drink alcohol. She takes no medications. Vital signs are within normal limits. Physical examination shows prominent frontal bossing, a protuberant mandible with spaces between the teeth, and large hands and feet. Serum studies show:
Na+ 140 mEq/L
Cl− 102 mEq/L
K+ 4.1 mEq/L
Ca2+ 10.6 mg/dL
Phosphorus 4.7 mg/dL
Glucose 180 mg/dL
Which of the following is the most likely sequela of this patient's condition?"

Question:
Serum studies show:
Na+ 140 mEq/L
Cl− 102 mEq/L
K+ 4.1 mEq/L
Ca2+ 10.6 mg/dL
Phosphorus 4.7 mg/dL
Glucose 180 mg/dL
Which of the following is the most likely sequela of this patient's condition?"

Answer: Reduced cardiac output


Context: An investigator is studying a local anesthetic that activates both alpha and beta adrenergic receptors. When given intravenously, it causes euphoria and pupillary dilation. Which of the following is the most likely effect of this drug at the synaptic cleft?

Question: Which of the following is the most likely effect of this drug at the synaptic cleft?

Answer: Decreased reuptake of norepinephrine


Context: A 35-year-old male is brought into the emergency department for a trauma emergency. The emergency medical services states that the patient was wounded with a knife on his upper left thigh near the inguinal ligament. Upon examination in the trauma bay, the patient is awake and alert. His physical exam and FAST exam is normal other than the knife wound. Large bore intravenous lines are inserted into the patient for access and fluids are being administered. Pressure on the knife wound is being held by one of the physicians with adequate control of the bleeding, but the physician notices the blood was previously extravasating in a pulsatile manner. His vitals are BP 100/50, HR 110, T 97.8, RR 22. What is the next best step for this patient?

Question: What is the next best step for this patient?

Answer: Coagulation studies and blood typing/crossmatch


Context:
Five days after undergoing surgical repair of a hip fracture, a 71-year-old man is agitated and confused. Last night, he had to be restrained multiple times after attempting to leave his room. His overnight nurse reported that at times he would be resting, but shortly afterward he would become agitated again for no clear reason. He has hypertension and COPD. He had smoked one pack of cigarettes daily for 50 years but quit 10 years ago. He drinks 1 glass of whiskey per day. His current medications include oxycodone, hydrochlorothiazide, albuterol, and ipratropium. He appears agitated. His temperature is 37°C (98.6°F), pulse is 72/min, and blood pressure is 141/84 mm Hg. Pulmonary examination shows a prolonged expiratory phase but no other abnormalities. Neurologic examination shows inattentiveness and no focal findings. He is oriented to person but not to place or time. During the examination, the patient attempts to leave the room after pulling out his intravenous line and becomes violent. He is unable to be verbally redirected and is placed on soft restraints. Laboratory studies show:
Hemoglobin 14.5 g/dL
Leukocyte count 8,000/mm3
Platelet count 245,000/mm3
Serum
Na+ 142 mEq/L
K+ 3.5 mEq/L
Cl- 101 mEq/L
HCO3- 24 mEq/L
Urea nitrogen 14 mg/dL
Creatinine 1.1 mg/dL
Urine dipstick shows no abnormalities. Which of the following is the most appropriate next step in management?"

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

Answer: Administer haloperidol


Context: An 18-year-old man presents to a rural emergency department after being stabbed multiple times. The patient's past medical history is notable for obesity, diabetes, chronic upper respiratory infections, a 10 pack-year smoking history, and heart failure. He is protecting his airway and he is oxygenating and ventilating well. His temperature is 97.6°F (36.4°C), blood pressure is 74/34 mmHg, pulse is 180/min, respirations are 24/min, and oxygen saturation is 98% on room air. The patient is started on whole blood and the surgeon on call is contacted to take the patient to the operating room. During the secondary survey, the patient complains of shortness of breath. His blood pressure is 54/14 mmHg, pulse is 200/min, respirations are 24/min, and oxygen saturation is 90% on room air. Physical exam is notable for bilateral wheezing on lung exam. The patient goes into cardiac arrest and after 30 minutes, attempts at resuscitation are terminated. Which of the following is associated with this patient's decompensation during resuscitation?

Question: Which of the following is associated with this patient's decompensation during resuscitation?

Answer: IgA deficiency


Context:
A 10-year-old boy is brought in by his mother with increasing abdominal pain for the past week. The patient’s mother says he has been almost constantly nauseous over that time. She denies any change in his bowel habits, fever, chills, sick contacts or recent travel. The patient has no significant past medical history and takes no medications. The patient is at the 90th percentile for height and weight and has been meeting all developmental milestones. The temperature is 36.8℃ (98.2℉). On physical examination, the patient’s abdomen is asymmetrically distended. Bowel sounds are normoactive. No lymphadenopathy is noted. A cardiopulmonary examination is unremarkable. Palpation of the right flank and right iliac fossa reveals a 10 × 10 cm firm mass which is immobile and tender. The laboratory findings are significant for the following:
Hemoglobin 10 g/dL
Mean corpuscular volume 88 μm3
Leukocyte count 8,000/mm3
Platelet count 150,000/mm3
    Serum creatinine 1.1 mg/dL
Serum lactate dehydrogenase (LDH) 1,000 U/L
An ultrasound-guided needle biopsy of the flank mass was performed, and the histopathologic findings are shown in the exhibit (see 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: Burkitt lymphoma


Context:
A 26-year-old woman seeks evaluation at an urgent care clinic with complaints of fever and generalized muscle and joint pain for the past 3 days. She also complains of nausea, but denies vomiting. She does not mention any past similar episodes. Her past medical history is unremarkable, but she returned to the United States 1 week ago after spending 2 weeks in southeast Asia doing charity work. She received all the recommended vaccines prior to traveling. The temperature is 40.0°C (104.0°F), the respirations are 15/min, the pulse is 107/min, and the blood pressure is 98/78 mm Hg. Physical examination shows mild gingival bleeding and a petechial rash over the trunk. Laboratory studies show the following:
Laboratory test
Leukocyte count 4,000/mm³
Platelet count 100,000/mm³
Partial thromboplastin time (activated)  45 seconds
Which of the following is the most likely cause of this patient’s condition?

Question:
Laboratory studies show the following:
Laboratory test
Leukocyte count 4,000/mm³
Platelet count 100,000/mm³
Partial thromboplastin time (activated)  45 seconds
Which of the following is the most likely cause of this patient’s condition?

Answer: Dengue fever


Context: A 24-year-old man presents with a complaint of breathlessness while jogging. He says that he recently started marathon training. He does not have any family history of asthma nor has any allergies. He currently takes no medication. The blood pressure is 120/80 mm Hg, and the heart rate is 67/min. With each heartbeat, he experiences pounding in his chest, and his head bobs. On physical examination, he has long fingers, funnel chest, and disproportionate body proportions with a longer length of the upper body compared to the lower body. On auscultation over the 2nd right intercostal space, an early diastolic murmur is heard, and 3rd and 4th heart sounds are heard. Echocardiography shows aortic root dilatation. The patient is scheduled for surgery. Which of the following is associated with this patient’s condition?

Question: Which of the following is associated with this patient’s condition?

Answer: Marfan's Syndrome


Context: A 62-year-old man comes to the physician for evaluation of an increasing right-sided cheek swelling for 2 years. He has had recurrent right-sided oral ulcers for the past 2 months. He has smoked a pack of cigarettes daily for 30 years. He drinks a beer every night. His temperature is 37.1°C (98.8°F), pulse is 71/min, respirations are 14/min, and blood pressure is 129/83 mm Hg. Examination shows a mild, nontender swelling above the angle of the right jaw. There is no overlying erythema or induration. There are multiple shallow ulcers on the right buccal mucosa and mandibular marginal gingiva. There is no lymphadenopathy. Ultrasound shows a soft tissue mass in the parotid gland. An ultrasound-guided biopsy of the mass confirms the diagnosis of parotid adenoid cystic carcinoma. A right-sided total parotidectomy is scheduled. This patient is at greatest risk for which of the following early complications?

Question: This patient is at greatest risk for which of the following early complications?

Answer: Paralysis of the right lower lip


Context: A 52-year-old man comes to the physician because of a 6-month history of shortness of breath and nonproductive cough. He has smoked 1 pack of cigarettes daily for 15 years. Cardiopulmonary examination shows fine inspiratory crackles bilaterally. There is clubbing present in the fingers bilaterally. Pulmonary function tests (PFTs) show an FVC of 78% of expected and an FEV1/FVC ratio of 92%. A CT scan of the chest is shown. Which of the following is the most likely underlying diagnosis?

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

Answer: Pulmonary fibrosis


Context: A 45-year-old man comes to the physician because of a 5-day history of fever, malaise, and right upper abdominal pain. Examination of the abdomen shows tenderness in the right upper quadrant. His leukocyte count is 18,000/mm3 (90% neutrophils) and serum alkaline phosphatase is 130 U/L. Ultrasonography of the abdomen shows a 3-cm hypoechoic lesion in the right lobe of the liver with a hyperemic rim. Which of the following is the most likely underlying cause of this patient's condition?

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

Answer: Cholangitis


Context: A 40-year-old male presents to the physician's office complaining of an inability to push doors open. He has had this problem since he was playing football with his children and was tackled underneath his right arm on his lateral chest. On examination, he has a winged scapula on the right side. Which of the following nerves is most likely the cause of this presentation?

Question: Which of the following nerves is most likely the cause of this presentation?

Answer: Long thoracic nerve


Context: A previously healthy 52-year-old man comes to the physician because of a 4-month history of recurrent abdominal pain, foul-smelling, greasy stools, and a 5-kg (11-lb) weight loss despite no change in appetite. Physical examination shows pain on palpation of the right upper quadrant. His fasting serum glucose concentration is 186 mg/dL. Abdominal ultrasound shows multiple round, echogenic foci within the gallbladder lumen with prominent posterior acoustic shadowing. The serum concentration of which of the following substances is most likely to be increased in this patient?

Question: The serum concentration of which of the following substances is most likely to be increased in this patient?

Answer: Somatostatin


Context: A 59-year-old man comes to the physician for a follow-up examination after being diagnosed with localized prostate cancer 3 weeks ago. The physician is delayed because of an emergency with another patient; miscommunication between the physician and his staff created further delays. When he enters the patient's room, the patient angrily expresses, “Do you realize that I waited 45 minutes in the waiting room, despite arriving on time, and that I've now waited another half an hour in this exam room? I am dying; do you have no respect for my time?” Which of the following is the most appropriate response by the physician?

Question: I am dying; do you have no respect for my time?” Which of the following is the most appropriate response by the physician?

Answer: """I apologize for the inconvenience, and if I were you I would be frustrated and angry as well. Let's talk about your concerns."""


Context: A 43-year-old woman presents to her primary care provider for follow-up of her glucose levels. At her last visit 3 months ago, her fasting serum glucose was 128 mg/dl. At that time, she was instructed to follow a weight loss regimen consisting of diet and exercise. Her family history is notable for a myocardial infarction in her father and type II diabetes mellitus in her mother. She does not smoke and drinks 2-3 glasses of wine per week. Her temperature is 99°F (37.2°C), blood pressure is 131/78 mmHg, pulse is 80/min, and respirations are 17/min. Her BMI is 31 kg/m^2. On exam, she is well-appearing and appropriately interactive. Today, despite attempting to make the appropriate lifestyle changes, a repeat fasting serum glucose is 133 mg/dl. The patient is prescribed the first-line oral pharmacologic agent for her condition. Which of the following is the correct mechanism of action of this medication?

Question: Which of the following is the correct mechanism of action of this medication?

Answer: Inhibition of hepatic gluconeogenesis


Context: A 26-year-old woman, G1P0, at 22 weeks of gestation presents to the clinic for a prenatal visit. Her recent pregnancy scan shows a single live intrauterine fetus with adequate fetal movements. Facial appearance shows the presence of a cleft lip. The rest of the fetal development is within normal limits. The fetal heart rate is 138/min. Her prenatal screening tests for maternal serum α-fetoprotein (MSAFP) concentration, pregnancy-associated plasma protein-A (PAPP-A), and free β-human chorionic gonadotropin (β-hCG) are within normal ranges respectively. Her past medical and surgical histories are negative. She is worried about the health of her baby. The baby is at increased risk for which of the following birth defects?

Question: The baby is at increased risk for which of the following birth defects?

Answer: Respiratory difficulty


Context: A 10-year-old boy is brought to the pediatrician by his mother for evaluation. Last night, he was playing with his younger brother and a hot cup of coffee fell on his left shoulder. Though his skin became red and swollen, he acted as if nothing happened and did not complain of pain or discomfort. He has met all expected developmental milestones, and his vaccinations are up-to-date. Physical examination reveals a normal appearing boy with height and weight in the 56th and 64th percentiles for his age, respectively. The skin over his left shoulder is erythematous and swollen. Sensory examination reveals impaired pain and temperature sensation in a cape-like distribution across both shoulders, arms, and neck. The light touch, vibration, and position senses are preserved. The motor examination is within normal limits, and he has no signs of a cerebellar lesion. His gait is normal. Which of the following disorders is most likely associated with this patient’s condition?

Question: Which of the following disorders is most likely associated with this patient’s condition?

Answer: Arnold-Chiari malformation


Context: A 61-year-old woman comes to the physician because of a constant, dull headache and generalized body pains for the past 8 months. She has also had difficulty hearing from her left side, which started a month after the onset of the headaches. Five months ago, she had surgery to correct a fracture of the right femur that occurred without a fall or any significant trauma. Five years ago, she underwent a total thyroidectomy for localized thyroid carcinoma. She takes levothyroxine and calcium supplements, which she started after menopause. Physical examination reveals a prominent forehead and irregular, tender skull surface. Bony tenderness is present over bilateral hip and knee joints, with decreased range of motion of the right hip joint and increased anterior curvature of both tibias. Laboratory studies show a highly elevated level of alkaline phosphatase, with vitamin D, calcium and PTH levels within normal limits. A plain x-ray of the head is most likely to show which of the following findings?

Question: A plain x-ray of the head is most likely to show which of the following findings?

Answer: Mixed lytic and sclerotic lesions


Context: A 65-year-old man comes to the physician because of a 1-month history of progressive back pain. He has also had a 5-kg (11-lb) weight loss over the past 3 months. His only medications are a daily multivitamin and ibuprofen, which he takes daily for the back pain. Physical examination shows tenderness to palpation over the lower spine and the left iliac crest. His hemoglobin concentration is 9.3 g/dL, his serum calcium concentration is 12 mg/dL, and his serum creatinine concentration is 2.1 mg/dL. A bone marrow biopsy shows 21% plasma cells. A diagnosis of multiple myeloma is established. In preparation for an autologous hematopoietic stem cell transplantation, the patient receives a myeloablative treatment regimen that includes busulfan. Which of the following drugs acts via a similar mechanism of action to busulfan?

Question: Which of the following drugs acts via a similar mechanism of action to busulfan?

Answer: Lomustine


Context:
Background: Beta-blockers reduce mortality in patients who have chronic heart failure, systolic dysfunction, and are on background treatment with diuretics and angiotensin-converting enzyme inhibitors. We aimed to compare the effects of carvedilol and metoprolol on clinical outcome.
Methods: In a multicenter, double-blind, randomized parallel group trial, we assigned 1511 patients with chronic heart failure to treatment with carvedilol (target dose, 25 mg twice daily) and 1518 to metoprolol (target dose, 50 mg twice daily). The patients were required to have chronic heart failure (NYHA II-IV), the previous admission for a cardiovascular indication, an ejection fraction of < 0.35, and to have been treated optimally with diuretics and angiotensin-converting enzyme inhibitors unless not tolerated. The primary endpoints were all-cause mortality and the composite endpoint of all-cause mortality or all-cause admission. The analysis was done by intention-to-treat.
Findings: The mean study duration was 58 months (SD, 6). The mean ejection fraction was 0.26 (SD, 0.07) and the mean age was 62 years (SD, 11). The all-cause mortality was 34% (512 of 1511) for carvedilol and 40% (600 of 1518) for metoprolol (hazard ratio, 0.83 [95% CI 0.74-0.93], p = 0.0017). The reduction in all-cause mortality was consistent across pre-defined subgroups. The incidence of side effects and drug withdrawals did not differ significantly between the 2 study groups.
Based on the best interpretation of the results of this clinical trial, which of the following statements is most accurate?

Question: Based on the best interpretation of the results of this clinical trial, which of the following statements is most accurate?

Answer: Carvedilol demonstrated a significant improvement in all-cause mortality in patients with heart failure as compared to metoprolol.


Context: A 27-year-old man is brought into the emergency department by ambulance. The patient was at an appointment to receive welfare when he began acting abnormally. The patient was denied welfare. Shortly afterwards, he no longer responded to questions and stared blankly off into space, not responding to verbal stimuli. Other than odd lip-smacking behavior, he was motionless. Several minutes later, he became responsive but seemed confused. The patient has a past medical history of drug abuse and homelessness and is not currently taking any medications. His temperature is 98.9°F (37.2°C), blood pressure is 124/78 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam reveals cranial nerves II-XII as grossly intact with 5/5 strength in the upper and lower extremities and a stable gait. The patient seems confused when answering questions and has trouble remembering the episode. Which of the following is the most likely diagnosis?

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

Answer: Complex partial seizure


Context: An 89-year-old woman presents to clinic complaining of a cough. She reports that she has never had a cough like this before. She takes a deep breath and then coughs multiple times, sometimes so much that she vomits. When she tries to catch her breath after a coughing spell, she has difficulty. She reports the cough has persisted for 3 weeks and usually comes in fits. Vital signs are stable. Physical examination is benign. You send cultures and a PCR of her secretions, both of which come back positive for the organism you had suspected. You tell her to stay away from her grandchildren because her illness may be fatal in infants. You also start her on medication. The illness affecting this patient would be best treated by a class of antibiotics...

Question: The illness affecting this patient would be best treated by a class of antibiotics...

Answer: that may prolong the QT interval


Context: A 27-year-old Caucasian female presents to her physician for episodes of urinary incontinence that began shortly after a breakup with her boyfriend. She claimed to be psychologically devastated when she found him sleeping with her brother and has had trouble caring for herself ever since. The patient states that the episodes came on suddenly and occur randomly. The patient denies any burning or pain upon urination. Upon obtaining further history, the patient also states that she has "stress spells" in which her vision becomes blurry or has blind spots. The patient also complains of frequent headaches. These symptoms have persisted for the past few years and she attributes them to arguments with her boyfriend. Embarrassed, the patient even admits to episodes of fecal incontinence which she also blames on her boyfriend's perpetual verbal and occasional physical abuse. The patient is teary and a physical exam is deferred until her mood improves. 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: Magnetic resonance imaging (MRI) of the head


Context: A 25-year-old man presents with an ulcer on his penis. He says that he noticed the ulcer a week ago while taking a shower and it has not improved. He denies any pain, penile discharge, rash, dysuria, fever, or pain on urination. His past medical history is nonsignificant. Sexual history reveals that the patient has had 6 male partners over the past year and uses condoms infrequently. On physical examination, there is a 1-cm ulcer on the dorsal aspect of the penile shaft (see image below). The edge and base of the ulcer are indurated but there is no bleeding or drainage. Two enlarged non-tender inguinal lymph nodes are palpable on the right. There is no evidence of scrotal masses or urethral discharge. A rapid HIV test is negative. Which of the following microorganisms is most likely responsible for this patient’s condition?

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

Answer: Treponema pallidum


Context:
A 56-year-old man presents to his physician’s office with a sudden increase in urinary frequency. During the past month, he has observed that he needs more frequent bathroom breaks. This is quite unusual as he hasn’t been consuming extra fluids. He reports feeling generally unwell over the past 2 months. He has lost over 7 kg (15.4 lb) of weight and has also been feeling progressively fatigued by the end of the day. He also has a persistent cough and on a couple of occasions, he noticed blood streaks on his napkin. In addition to all of this, he has been feeling weak with frequent muscle cramps during the day. He has never been diagnosed with any medical condition in the past. He doesn’t drink but has smoked 2 packs of cigarettes daily for the last 25 years. Prior to his appointment, he took a couple of tests. The results are given below:
Hemoglobin (Hb) 13.1 g/dL
Serum creatinine 0.8 mg/dL
Serum urea 13 mg/dL
Serum sodium 129 mEq/L
Serum potassium 3.2 mEq/L
His chest X-ray shows a central nodule with some hilar thickening. The physician recommends a biopsy of the nodule. Which of the following histological patterns is the nodule most likely to exhibit?

Question: Which of the following histological patterns is the nodule most likely to exhibit?

Answer: Kulchitsky cells with hyperchromatic nuclei


Context: A 31-year-old man presents to his primary care physician endorsing three months of decreased sleep. He reports an inability to fall asleep; although once asleep, he generally sleeps through the night and wakes up at a desired time. He has instituted sleep hygiene measures, but this has not helped. He has not felt anxious or depressed and is otherwise healthy. You prescribe him a medication that has the potential side effect of priapism. From which of the following locations is the neurotransmitter affected by this medication released?

Question: From which of the following locations is the neurotransmitter affected by this medication released?

Answer: Raphe nucleus


Context: A mother brings her 3-year-old son to his pediatrician because he is having tantrums. The boy has no history of serious illness and is on track with developmental milestones. His mother recently returned to work 2 weeks ago. She explains that, since then, her son has had a tantrum roughly every other morning, usually when she is getting him dressed or dropping him off at daycare. He cries loudly for about 5 minutes, saying that he does not want to go to daycare while thrashing his arms and legs. According to the daycare staff, he is well-behaved during the day. In the evenings, he has tantrums about twice per week, typically when he is told he must finish his dinner or that it is time for bed. These tantrums have been occurring for about 6 months. The mother is concerned her son may have a behavioral disorder. Which of the following is the most likely cause of the boy's behavior?

Question: Which of the following is the most likely cause of the boy's behavior?

Answer: Normal development


Context: A 35-year-old woman comes to the physician because of a 3-month history of progressive fatigue, shortness of breath, and pain in her knees and ankles. Her temperature is 37.6°C (99.7°F). Physical examination shows mild hepatomegaly and tender, red nodules on her shins. There are purple, indurated lesions on her nose, nasolabial fold, and cheeks. A biopsy of the liver shows scattered aggregations of multinucleated giant cells with cytoplasmic inclusions and eosinophilic, needle-shaped structures arranged in a star-like pattern. 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: Sarcoidosis


Context: A 63-year-old man presents to the ambulatory medical clinic with symptoms of dysphagia and ‘heartburn’, which he states have become more troublesome over the past year. Past medical history is significant for primary hypertension. On physical exam, he is somewhat tender to palpation over his upper abdomen. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 74/min, and respiratory rate 14/min. Barium swallow fluoroscopy demonstrates a subdiaphragmatic gastroesophageal junction, with herniation of the gastric fundus into the left hemithorax. Given the following options, what is the most appropriate next step in the management of this patient’s underlying condition?

Question: Given the following options, what is the most appropriate next step in the management of this patient’s underlying condition?

Answer: Surgical gastropexy


Context: A 71-year-old man presents to his cardiologist with a 1-month history of increasing shortness of breath. He says that he is finding it very difficult to walk up the flight of stairs to his bedroom and he is no longer able to sleep flat on his bed because he wakes up choking for breath. His past medical history is significant for a myocardial infarction 3 years ago. On physical exam, he is found to have diffuse, moist crackles bilaterally on pulmonary auscultation and pitting edema in his lower extremities. Serum tests reveal an increased abundance of a product produced by cardiac myocytes. Which of the following most likely describes the function of this product?

Question: Which of the following most likely describes the function of this product?

Answer: Inhibits release of renin


Context: A 50-year-old farmer presents to a physician with painless, black, severely swollen pustules on the left hand. Examination reveals extensive swelling around the wound. Microscopy reveals gram-positive bacilli with a bamboo stick appearance. Culture shows large, gray, non-hemolytic colonies with irregular borders. Which of the following is the most likely diagnosis?

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

Answer: Anthrax


Context: A 64-year-old woman comes to the physician because of a 4-month history of vulvar itching and dryness. During this period, she has also had pain during sexual intercourse but no postcoital bleeding. Her last menstrual period was at the age of 51 years. She has type 2 diabetes mellitus and her only medication is metformin. Pelvic examination shows atrophic labial folds. There are excoriation marks and a well-demarcated, white plaque on the vulva. The remainder of the examination shows no abnormalities. The results of biopsy rule out cancer. Which of the following is the most appropriate next step in treatment for this patient's lesions?

Question: Which of the following is the most appropriate next step in treatment for this patient's lesions?

Answer: Topical clobetasol


Context: A male newborn delivered at 32 weeks' gestation to a 41-year-old woman dies shortly after birth. The mother did not receive prenatal care and consistently consumed alcohol during her pregnancy. At autopsy, examination shows microcephaly, an eye in the midline, a cleft lip, and a single basal ganglion. Failure of which of the following processes is the most likely cause of this condition?

Question: Failure of which of the following processes is the most likely cause of this condition?

Answer: Cleavage of the forebrain


Context: In 2013 the national mean score on the USMLE Step 1 exam was 227 with a standard deviation of 22. Assuming that the scores for 15,000 people follow a normal distribution, approximately how many students scored above the mean but below 250?

Question: Assuming that the scores for 15,000 people follow a normal distribution, approximately how many students scored above the mean but below 250?

Answer: 5,100


Context: A 53-year-old man with a past medical history significant for hyperlipidemia, hypertension, and hyperhomocysteinemia presents to the emergency department complaining of 10/10 crushing, left-sided chest pain radiating down his left arm and up his neck into the left side of his jaw. His ECG shows ST-segment elevation in leads V2-V4. He is taken to the cardiac catheterization laboratory for successful balloon angioplasty and stenting of a complete blockage in his left anterior descending coronary artery. Echocardiogram the following day shows decreased left ventricular function and regional wall motion abnormalities. A follow-up echocardiogram 14 days later shows a normal ejection fraction and no regional wall motion abnormalities. This post-infarct course illustrates which of the following concepts?

Question: This post-infarct course illustrates which of the following concepts?

Answer: Myocardial stunning


Context: A 64-year-old man is brought to the emergency department because of fever, chills, shortness of breath, chest pain, and a productive cough with bloody sputum for the past several days. He has metastatic pancreatic cancer and is currently undergoing polychemotherapy. His temperature is 38.3°C (101°F). Pulmonary examination shows scattered inspiratory crackles in all lung fields. A CT scan of the chest shows multiple nodules, cavities, and patchy areas of consolidation. A photomicrograph of a specimen obtained on pulmonary biopsy is shown. Which of the following is the most likely causal pathogen?

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

Answer: Aspergillus fumigatus


Context:
A 10-month-old girl is brought to the physician by her mother because of fever and irritability for the past 2 days. The mother says that the girl's diapers have smelled bad since the symptoms started. The patient has had some clear nasal secretions over the past week. Two months ago, she was brought to the emergency department for a simple febrile seizure. Otherwise, she has been healthy and her immunizations are up-to-date. She appears ill. She is at the 50th percentile for height and weight. Her temperature is 39.1°C (102.3°F), pulse is 138/min, respirations are 26/min, and blood pressure is 75/45 mm Hg. Oropharyngeal examination shows a mild postnasal drip. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 12.4 g/dL
Leukocyte count
8,000/mm3
Serum
Na+ 138 mEq/L
K+ 4.0 mEq/L
Cl- 100 mEq/L
Creatinine 0.5 mg/dL
Urine
RBC 1–2/hpf
WBC 18–20 WBCs/hpf
Nitrites positive
Bacteria gram-negative rods
Nasal swab for respiratory syncytial virus, influenza A, and influenza B antigens is negative. Urine culture grows > 105 colony forming units (CFU)/mL of E. coli. Treatment with acetaminophen and cefixime is started. Two days later, her symptoms have improved. 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: Perform renal and bladder ultrasound


Context: A 33-year-old woman presents to the physician because of abdominal discomfort, weakness, and fever. She has had a significant weight loss of 15 kg (33.1 lb) over the past 2 months. She has no history of medical illness and is not on any medications. Her pulse is 96/min, the blood pressure is 167/92 mm Hg, the respiratory rate is 20/min, and the temperature is 37.7°C (99.8°F). Her weight is 67 kg (147.71 lb), height is 160 cm (5 ft 3 in), and BMI is 26.17 kg/m2. Abdominal examination shows purple striae and a vaguely palpable mass in the left upper quadrant of the abdomen, which does not move with respirations. She has coarse facial hair and a buffalo hump along with central obesity. Her extremities have poor muscle bulk, and muscle weakness is noted on examination. An ultrasound of the abdomen demonstrates an adrenal mass with para-aortic lymphadenopathy. Which of the following is the most likely laboratory profile in this patient?

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

Answer: Impaired glucose tolerance, elevated serum cortisol, elevated 24-h urinary free cortisol, and low plasma ACTH


Context: A 52-year-old man presents to the office for a regular health checkup. He was diagnosed with type 2 diabetes mellitus 6 years ago and has been taking metformin alone. Over the past year, his daily blood glucose measurements have gradually been increasing. During his previous visit, his HbA1c level was 7.9% and the doctor mentioned the possibility of requiring an additional medication to keep his blood sugar under better control. Today, his HbA1c is 9%. The doctor mentions a research article that has been conducted on a randomized and controlled group of 200 subjects studying a new anti-diabetic medication. It has been shown to significantly reduce glucose levels and HbA1c levels compared to the current gold standard treatment. Possible adverse effects, however, are still being studied, though the authors believe that they will be minimal. In this study, what would most likely increase the chances of detecting a significant adverse effect?

Question: In this study, what would most likely increase the chances of detecting a significant adverse effect?

Answer: Increasing sample size


Context: A 5-year-old girl is brought in for a routine checkup. She was born at 39 weeks gestation via spontaneous vaginal delivery and is up to date on all vaccines and is meeting all developmental milestones. Upon examination, she is pale with a few petechiae on her chest neck and back. Examination of the abdomen reveals painless hepatosplenomegaly. Liver enzymes are mildly elevated and complete blood cell count shows slight anemia and thrombocytopenia. Iron, B12, and folate are normal. A bone marrow biopsy shows mildly hypocellular marrows with diffuse macrophages with eosinophilic cytoplasm. The cytoplasm looks like wrinkled tissue paper on further inspection. No blasts are observed. What is the most likely diagnosis in the present case?

Question: What is the most likely diagnosis in the present case?

Answer: Gaucher disease type I


Context: A 15-year-old boy presents to the emergency department after a rusty nail pierced through his right foot. He was able to pull out the nail, but not able to walk on his foot. He believes he had all his shots as a child, with the last one just before starting middle school at the age of 12. The vital signs are within normal limits. Physical examination reveals a 0.5-inch puncture wound on the right heel. The site is tender, erythematous, with flecks of reddish-brown particles in the base. No blood or discharge is seen. Which of the following is the most appropriate next step in management?

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

Answer: Administer Td and TIG


Context: An 11-year-old boy presents to the emergency department with sudden pain. The patient's parents state the child suddenly felt pain in his hands an hour ago. He has not eaten anything new lately. He did play football earlier this morning and admits to being tackled forcefully multiple times. The child is doing well in school and is proud that he has a new girlfriend. The child has a past medical history of obesity and is not currently on any medications. His temperature is 100°F (37.8°C), blood pressure is 120/68 mmHg, pulse is 100/min, respirations are 11/min, and oxygen saturation is 98% on room air. Cardiopulmonary exam is within normal limits. On physical exam of the patient's extremities, there was painful and symmetrical swelling of his hands and feet but no rashes were present. The patient is started on analgesics. Which of the following is the most likely cause of this patient's presentation?

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

Answer: Altered red blood cell morphology


Context:
An 8-year-old boy is brought to the physician because of worsening confusion and lethargy for the last hour. He has had high-grade fever, productive cough, fatigue, and malaise for 2 days. He was diagnosed with sickle cell anemia at the age of 2 years but has not seen a physician in over a year. His temperature is 38.9°C (102°F), pulse is 133/min, respirations are 33/min, and blood pressure is 86/48 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 92%. The patient does not respond to verbal commands. Examination shows conjunctival pallor and scleral icterus. Inspiratory crackles are heard at the left lung base. Laboratory studies show:
Hemoglobin 8.1 g/dL
Leukocyte count 17,000/mm3
Platelet count 200,000/mm3
Which of the following is most likely to have prevented this patient's condition?"

Question:
Laboratory studies show:
Hemoglobin 8.1 g/dL
Leukocyte count 17,000/mm3
Platelet count 200,000/mm3
Which of the following is most likely to have prevented this patient's condition?"

Answer: Polysaccharide vaccination


Context: A 4-month-old boy is brought by his mother to the pediatrician for a routine check-up. He was born at 39 weeks’ gestation. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. The child has been breastfeeding well and sleeping through the night. He smiles spontaneously and has started to babble. He is up to date on all his vaccinations. His temperature is 98.6°F (37°C), blood pressure is 130/85 mmHg, pulse is 82/min, and respirations are 20/min. On exam, he is able to hold his head steady while unsupported and is noted to roll over from the prone to the supine position. Mild hepatomegaly is noted along with palpable bilateral abdominal masses. This patient’s condition is associated with a mutation in which of the following chromosomes?

Question: This patient’s condition is associated with a mutation in which of the following chromosomes?

Answer: 6


Context:
A 50-year-old man visits his primary care practitioner for a general health check-up. He was recently hired as a fitness instructor at a local fitness center. His father died of advanced colorectal cancer, however, his personal medical history is significant for the use of performance-enhancing drugs during his 20’s when he competed in bodybuilding and powerlifting competitions. As part of the paperwork associated with his new position, he received an order for a hemoglobin and hematocrit, occult blood in stool, and serum iron and ferritin level, shown below:
Hemoglobin  11.8 g/dL
Hematocrit  35%
Iron 40 µg/dL
Ferritin 8 ng/mL
His fecal occult blood test was positive. Which of the following is the most recommended follow-up action?

Question: Which of the following is the most recommended follow-up action?

Answer: Endoscopy and colonoscopy


Context: A 14-year-old girl is brought to the pediatrician by her mother. The girl's mother states that she began having her period 6 months ago. The patient states that after her first period she has had a period every 10 to 40 days. Her menses have ranged from very light flow to intense and severe symptoms. Otherwise, the patient is doing well in school, is on the track team, and has a new boyfriend. Her temperature is 98.1°F (36.7°C), blood pressure is 97/58 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 99% on room air. Physical exam demonstrates an obese girl but is otherwise within normal limits. Which of the following is the most likely diagnosis?

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

Answer: Normal development


Context: A 79-year-old man is admitted to the intensive care unit for hospital acquired pneumonia, a COPD flare, and acute heart failure requiring intubation and mechanical ventilation. On his first night in the intensive care unit, his temperature is 99.7°F (37.6°C), blood pressure is 107/58 mm Hg, and pulse is 150/min which is a sudden change from his previous vitals. Physical exam is notable for jugular venous distension and a rapid heart rate. The ventilator is checked and is functioning normally. Which of the following is the best next step in management for the most likely diagnosis?

Question: Which of the following is the best next step in management for the most likely diagnosis?

Answer: Needle thoracostomy


Context: A 67-year-old woman is admitted to the hospital because of a 2-day history of fever, headache, jaw pain, and decreased vision in the right eye. Her erythrocyte sedimentation rate is 84 mm per hour. Treatment with methylprednisolone is initiated but her symptoms do not improve. The physician recommends the administration of a new drug. Three days after treatment with the new drug is started, visual acuity in the right eye increases. The beneficial effect of this drug is most likely due to inhibition of which of the following molecules?

Question: The beneficial effect of this drug is most likely due to inhibition of which of the following molecules?

Answer: Interleukin-6


Context: A 65-year-old man comes to the physician for a routine health maintenance examination. He has a strong family history of colon cancer. A screening colonoscopy shows a 4 mm polyp in the upper sigmoid colon. Which of the following findings on biopsy is associated with the lowest potential for malignant transformation into colorectal carcinoma?

Question: Which of the following findings on biopsy is associated with the lowest potential for malignant transformation into colorectal carcinoma?

Answer: Hyperplastic epithelium at the base of crypts


Context: A 45-year-old man comes to the physician because of a 3-month history of recurrent headaches. The headaches are of a dull, nonpulsating quality. The patient denies nausea, vomiting, photophobia, or phonophobia. Neurologic examination shows no abnormalities. The physician prescribes a drug that irreversibly inhibits cyclooxygenase-1 and cyclooxygenase-2 by covalent acetylation. Which of the following medications was most likely prescribed by the physician?

Question: Which of the following medications was most likely prescribed by the physician?

Answer: Aspirin


Context: A 48-year-old Caucasian male suffering from ischemic heart disease is placed on a heart transplant list. Months later, he receives a heart from a matched donor. During an endomyocardial biopsy performed 3 weeks later, there is damage consistent with acute graft rejection. What is most likely evident on the endomyocardial biopsy?

Question: What is most likely evident on the endomyocardial biopsy?

Answer: Lymphocytic infiltrate


Context:
A 58-year-old woman is brought to the emergency department because of a 2-day history of increasing chest pain and shortness of breath. She has had a productive cough with foul-smelling sputum for 1 week. Seven months ago, the patient had an ischemic stroke. She has gastritis and untreated hypertension. She currently lives in an assisted-living community. She has smoked one pack of cigarettes daily for 40 years. She has a 20-year history of alcohol abuse, but has not consumed any alcohol in the past 4 years. Her only medication is omeprazole. She appears to be in respiratory distress and speaks incoherently. Her temperature is 39.3°C (102.7°F), pulse is 123/min, respirations are 33/min, and blood pressure is 155/94 mm Hg. Auscultation of the lung shows rales and decreased breath sounds over the right upper lung field. Examination shows weakness and decreased sensation of the right upper and lower extremities. Babinski sign and facial drooping are present on the right. Arterial blood gas analysis on room air shows:
pH 7.48
PCO2 31 mm Hg
PO2 58 mm Hg
O2 saturation 74%
A chest x-ray shows infiltrates in the right posterior upper lobe. Which of the following is the strongest predisposing factor for this patient's respiratory symptoms?"

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

Answer: A history of ischemic stroke


Context: A 36-year-old primigravid woman at 34 weeks' gestation comes to the physician because of a 1-week history of upper abdominal discomfort, nausea, and malaise. She had a mild upper respiratory tract infection a week ago. She has a 10-year history of polycystic ovarian syndrome and a 3-year history of hypertension. Her medications include metformin, labetalol, folic acid, and a multivitamin. Her pulse is 92/min, respirations are 18/min, and blood pressure is 147/84 mm Hg. Examination shows a nontender uterus consistent in size with a 34-week gestation. There is mild tenderness of the right upper quadrant of the abdomen. The fetal heart rate is reactive with no decelerations. 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: Serum transaminase levels and platelet count


Context: A 72-year-old woman presents to the emergency department for vision loss. She was reading a magazine this afternoon when she started having trouble seeing out of her left eye. Her vision in that eye got progressively darker, eventually becoming completely black over the course of a few minutes. It then returned to normal after about 10 minutes; she reports she can see normally now. She had no pain and no other symptoms then or now. Past medical history is notable for hypertension and hyperlipidemia. A high-pitched sound is heard when the diaphragm of the stethoscope is placed on her left neck, but her physical exam is otherwise unremarkable; vision is currently 20/30 bilaterally. The etiology of her symptoms most likely localizes to which of the following anatomic locations?

Question: The etiology of her symptoms most likely localizes to which of the following anatomic locations?

Answer: Carotid artery


Context: A 67-year-old man presents with pain in both legs. He says the pain is intermittent in nature and has been present for approx. 6 months. The pain increases with walking, especially downhill, and prolonged standing. It is relieved by lying down and leaning forward. Past medical history is significant for type 2 diabetes mellitus, hypercholesterolemia, and osteoarthritis. The patient reports a 56-pack-year history but denies any alcohol or recreational drug use. His vital signs include: blood pressure 142/88 mm Hg, pulse 88/min, respiratory rate 14/min, temperature 37°C (98.6°F). On physical examination, the patient is alert and oriented. Muscle strength is 5/5 in his upper and lower extremities bilaterally. Babinski and Romberg tests are negative. Pulses measure 2+ in upper and lower extremities bilaterally. Which of the following is the next best step in the management of this patient?

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

Answer: MRI of the spine


Context: A 28-year-old woman presents to a psychiatrist with a 10-year history of unexplained anxiety symptoms. To date, she has not visited any psychiatrist, because she believes that she should not take medicines to change her emotions or thoughts. However, after explaining the nature of her disorder, the psychiatrist prescribes daily alprazolam. When she comes for her first follow-up, she reports excellent relief from her symptoms without any side-effects. The psychiatrist encourages her to continue her medication for the next 3 months and then return for a follow-up visit. After 3 months, she tells her psychiatrist that she has been experiencing excessive sedation and drowsiness over the last few weeks. The psychiatrist finds that she is taking alprazolam in the correct dosage, and she is not taking any other medication that causes sedation. Upon asking her about any recent changes in her lifestyle, she mentions that for the last 2 months, she has made a diet change. The psychiatrist tells her that diet change may be the reason why she is experiencing excessive sedation and drowsiness. Which of the following is the most likely diet change the psychiatrist is talking about?

Question: Which of the following is the most likely diet change the psychiatrist is talking about?

Answer: Daily consumption of grapefruit juice


Context: A 13-year-old boy is brought to the emergency department by his parents for evaluation of severe groin pain for the past 4 hours. His symptoms began while he was participating in a basketball game. On arrival to the ED, the resident on call notes a swollen, tender, and elevated left testicle with absence of the cremasteric reflex. A urology consult is requested and the patient is scheduled for surgery. An abnormality in which of the following anatomical structures is most likely responsible for this patient’s condition?

Question: An abnormality in which of the following anatomical structures is most likely responsible for this patient’s condition?

Answer: Tunica vaginalis


Context: A 39-year-old male presents to the emergency department with fever, jaundice, and abdominal pain. The patient is a known intravenous drug-user. Serologic testing reveals an ALT of 1040 units/L, AST of 810 units/L, and titer evidence of infection with an enveloped, negative sense, single-stranded, closed circular RNA virus. Which of the following infections must also be present in this patient for him to develop his current disease?

Question: Which of the following infections must also be present in this patient for him to develop his current disease?

Answer: Hepatitis B virus


Context: A 5-day-old boy is brought to see his pediatrician after his newborn blood screening showed elevated levels of immunoreactive trypsinogen, a marker for cystic fibrosis. The boy was born at 39 weeks gestation after regular prenatal care. He has 2 siblings that tested negative on screening. On physical exam, his vitals are normal and he appears healthy. Which of the following tests should be performed next to evaluate the newborn for cystic fibrosis?

Question: Which of the following tests should be performed next to evaluate the newborn for cystic fibrosis?

Answer: Sweat test


Context: A 5-year-old girl is brought to the emergency department by her father due to a 6-day history of fevers and irritability. His father reports that the fevers have ranged from 101-104°F (38.3-40°C). He tried to give her ibuprofen, but the fevers have been unresponsive. Additionally, she developed a rash 3 days ago and has refused to wear shoes because they feel “tight.” Her father reports that other than 2 ear infections she had when she was younger, the patient has been healthy. She is up-to-date on her vaccinations except for the vaccine boosters scheduled for ages 4-6. The patient’s temperature is 103.5°F (39.7°C), blood pressure is 110/67 mmHg, pulse is 115/min, and respirations are 19/min with an oxygen saturation of 98% O2 on room air. Physical examination shows bilateral conjunctivitis, palpable cervical lymph nodes, a diffuse morbilliform rash, and desquamation of the palms and soles with swollen hands and feet. Which of the following the next step in management?

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

Answer: High dose aspirin


Context: A 15-year-old man presents with his father to the urgent care department with a 5-day history of frequent diarrhea, occasionally mixed with streaks of blood. Stool cultures are pending, but preliminary stool samples demonstrate fecal leukocytes and erythrocytes. The patient's vital signs are within normal limits, and he is started on outpatient therapy for presumed Shigella infection. Which of the following was the young man most likely started on?

Question: Which of the following was the young man most likely started on?

Answer: Oral trimethoprim-sulfamethoxazole (TMP-SMX)


Context: A 7-year-old boy with asthma is brought to the emergency department because of a 1-day history of shortness of breath and cough. Current medications are inhaled albuterol and beclomethasone. His temperature is 37°C (98.6°F) and respirations are 24/min. Pulmonary examination shows bilateral expiratory wheezing. Serum studies show increased concentrations of interleukin-5. Which of the following is the most likely effect of the observed laboratory finding in this patient?

Question: Which of the following is the most likely effect of the observed laboratory finding in this patient?

Answer: Recruitment of eosinophils


Context: Two days after admission for myocardial infarction and subsequent coronary angioplasty, a 65-year-old man becomes distressed and diaphoretic in the cardiac intensive care unit. Suddenly he is no longer responsive. Pulse oximetry does not show a tracing. He has a history of hypertension and depression. Prior to his admission, his medication included ramipril and aripiprazole. Examination shows no carotid pulse. An ECG is shown. After beginning chest compressions, which of the following is the most appropriate step in management of the patient?

Question: After beginning chest compressions, which of the following is the most appropriate step in management of the patient?

Answer: Defibrillation


Context: A 17-year-old girl comes to the physician because she had unprotected sexual intercourse the previous day. Menses have occurred at regular 28-day intervals since menarche at the age of 13 years. Her last menstrual period was 12 days ago. Physical examination shows no abnormalities. A urine pregnancy test is negative. She does not wish to become pregnant until after college and does not want her parents to be informed of this visit. Which of the following is the most appropriate step in management?

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

Answer:
Insert copper-containing intra-uterine device
"


Context: A 23-year-old Sicilian male presents to his primary care physician complaining of lethargy, joint pain, and urinary frequency. Vitals signs include T 98.7 F, HR 96 bpm, BP 135/71 mm/Hg, RR 18 breaths/minute, O2 99%. Laboratory findings include: random glucose 326 mg/dL, Hemoglobin 7.1, and elevated reticulocyte count and transferrin saturation. The patient is not surprised that his "blood level is low" and suggests that he might need another transfusion. An echocardiogram demonstrates restrictive cardiomyopathy. The disorder with which this patient presents can be characterized by which of the following?

Question: The disorder with which this patient presents can be characterized by which of the following?

Answer: Absence of the hemoglobin beta-chain


Context: A 55-year-old man who recently immigrated to the United States from Azerbaijan comes to the physician because of a 6-week history of recurrent fever, progressive cough with bloody streaks, fatigue, and a 3.6-kg (8-lb) weight loss. He has poorly-controlled type 2 diabetes mellitus treated with insulin. An x-ray of the chest shows a cavitary lesion of the posterior apical segment of the right upper lobe with consolidation of the surrounding parenchyma. He is started on a treatment regimen with a combination of drugs. A culture of the sputum identifies a causal pathogen that is resistant to a drug that alters the metabolism of pyridoxine. Which of the following is the most likely mechanism of resistance to this drug?

Question: Which of the following is the most likely mechanism of resistance to this drug?

Answer: Decreased production of catalase-peroxidase


Context: A 62-year-old man comes to the physician because of tremors in both hands for the past few months. He has had difficulty buttoning his shirts and holding a cup of coffee without spilling its content. He has noticed that his symptoms improve after a glass of whiskey. His maternal uncle began to develop similar symptoms around the same age. He has bronchial asthma controlled with albuterol and fluticasone. Examination shows a low-amplitude tremor bilaterally when the arms are outstretched that worsens during the finger-to-nose test. Which of the following is the most appropriate pharmacotherapy in this patient?

Question: Which of the following is the most appropriate pharmacotherapy in this patient?

Answer: Primidone


Context: A 34-year-old woman, who had her first child 2 weeks ago, visits her family physician with concerns about constant fatigue and difficulty with breastfeeding. She was discharged from the intensive care unit after hospitalization for severe postpartum hemorrhage. Since then, she has tried multiple pumps and self-stimulation to encourage breast milk production; however, neither of these strategies has worked. Her blood pressure is 88/56 mm Hg and heart rate is 120/min. Which of the following best explains the underlying condition of this patient?

Question: Which of the following best explains the underlying condition of this patient?

Answer: Pituitary infarction


Context:
A 54-year-old man is brought to the emergency department by his wife because of high fever and confusion for the past 10 hours. His wife reports that 1 week ago during a trip to Guatemala he underwent an emergency appendectomy. His temperature is 40.1°C (104.2°F), pulse is 132/min, and blood pressure is 74/46 mm Hg. He is oriented only to person. Physical examination shows a surgical wound in the right lower quadrant with purulent discharge. The skin is warm and dry. Serum studies show a sodium concentration of 138 mEq/L, potassium concentration of 3.7 mEq/L, and lactate concentration of 3.5 mEq/L (N = 0.5–2.2 mEq/L). Arterial blood gas analysis on room air shows:
pH 7.21
pCO2 36
HCO3- 12
O2 saturation 87%
Which of the following is the most likely explanation for these laboratory changes?"

Question:
Arterial blood gas analysis on room air shows:
pH 7.21
pCO2 36
HCO3- 12
O2 saturation 87%
Which of the following is the most likely explanation for these laboratory changes?"

Answer: Respiratory fatigue


Context: A 24-year-old college student presents to student health with 2 days of developing a sore throat, runny nose, and a cough that started today. He states that he has been getting mild fevers which began yesterday. On exam, his temperature is 102.0°F (38.9°C), blood pressure is 135/76 mmHg, pulse is 95/min, and respirations are 12/min. His physician recommends over-the-counter cold medications and reassures him that his symptoms are due to a viral infection that is self-limited. Which of the following best describes the most likely cause of his illness?

Question: Which of the following best describes the most likely cause of his illness?

Answer: Enveloped (+) ssRNA virus


Context: During an evaluation of a new diagnostic imaging modality for detecting salivary gland tumors, 90 patients tested positive out of the 100 patients who tested positive with the gold standard test. A total of 80 individuals tested negative with the new test out of the 100 individuals who tested negative with the gold standard test. What is the positive likelihood ratio for this test?

Question: What is the positive likelihood ratio for this test?

Answer: 90/20


Context: A 49-year-old man is brought to the emergency department after collapsing on the ground at a grocery store 30 minutes ago. His wife states that he complained of dizziness and chest pain prior to falling down. Medical history is significant for hypertension and diabetes mellitus. His wife says that he is not compliant with his medications. His temperature is 37.0°C (98.6°F), respiratory rate is 15/min, pulse rate is 67/min, and blood pressure is 122/98 mm Hg. Physical examination, including chest auscultation, is within normal limits. He is awake and in distress. The on-call resident who is evaluating him decides to do a 12-lead ECG, which is shown in the exhibit. The initial blood test results are normal. A second set of blood samples are sent to the lab after 6 hours. Which of the following results is most likely to be seen in this patient?

Question: Which of the following results is most likely to be seen in this patient?

Answer: Elevated troponins and elevated CK-MB


Context: A 33-year-old primigravid visits the clinic at the 22 weeks’ gestation with concerns about several episodes of loose watery stool over the past 4 months, which are sometimes mixed with blood. Use of over-the-counter antidiarrheal medications has not been helpful. She also reports having painful ulcers in her mouth for the last 2 months. Pregnancy has been otherwise uncomplicated so far. On physical examination, the blood pressure is 110/60 mm Hg, the pulse rate is 90/min, the respiratory rate is 19/min, and the temperature is 36.6°C (97.8°F). There is bilateral conjunctival redness. Abdominal examination shows minimal tenderness but no guarding or rebound tenderness. Fundal height is proportionate to 22 weeks of gestation, and fetal heart sounds are audible. Colonoscopy shows focal areas of inflammation in the ileum, separated by normal mucosa, with rectal sparing. Based on the colonoscopy results, which of the following complications is the patient at risk for?

Question: Based on the colonoscopy results, which of the following complications is the patient at risk for?

Answer: Intestinal obstruction


Context:
A 54-year-old man is brought to the emergency department 1 hour after an episode of loss of consciousness that lasted 3 minutes. Since awakening, he has had weakness of the left arm and leg, and his speech has been slurred. He has had a fever for 10 days. He has not had vomiting or headache. He was treated for bacterial sinusitis 3 weeks ago with amoxicillin-clavulanate. He has hypertension, hypothyroidism, hyperlipidemia, and type 2 diabetes mellitus. Current medications include amlodipine, hydrochlorothiazide, metformin, simvastatin, aspirin, and levothyroxine. His temperature is 38.6°C (101.4°F), pulse is 106/min, and blood pressure is 160/90 mm Hg. He is alert and oriented to person, place, and time. Examination shows multiple petechiae on his trunk and painless macules over both palms. A new grade 3/6 systolic murmur is heard best at the apex. He follows commands, but he slurs his words and has difficulty naming common objects. There is left facial droop. Muscle strength is 4/5 in the left upper and lower extremities. Deep tendon reflexes are 3+ on the left side and 2+ on the right side. The left big toe shows an extensor response. Fundoscopic examination shows retinal hemorrhages with white centers. Laboratory studies show:
Hemoglobin 15.3 g/dL
Leukocyte count 12,300/mm3
Serum
Na+ 136 mEq/L
Cl- 103 mEq/L
K+ 4.3 mEq/L
Glucose 108 mg/dL
Creatinine 1.1 mg/dL
Urine
Protein 1+
Glucose negative
Blood 1+
WBC 1–2/hpf
RBC 7–10/hpf
Which of the following is the most likely cause of these findings?"

Question:
Laboratory studies show:
Hemoglobin 15.3 g/dL
Leukocyte count 12,300/mm3
Serum
Na+ 136 mEq/L
Cl- 103 mEq/L
K+ 4.3 mEq/L
Glucose 108 mg/dL
Creatinine 1.1 mg/dL
Urine
Protein 1+
Glucose negative
Blood 1+
WBC 1–2/hpf
RBC 7–10/hpf
Which of the following is the most likely cause of these findings?"

Answer: Septic emboli


Context:
A 63-year-old male is accompanied by his wife to his primary care doctor complaining of shortness of breath. He reports a seven-month history of progressively worsening dyspnea and a dry non-productive cough. He has also lost 15 pounds over the same time despite no change in diet. Additionally, over the past week, his wife has noticed that the patient appears confused and disoriented. His past medical history is notable for stable angina, hypertension, hyperlipidemia, and diabetes mellitus. He currently takes aspirin, metoprolol, lisinopril, atorvastatin, metformin, and glyburide. He has smoked 1 pack of cigarettes per day for 30 years and previously worked as a mechanic at a shipyard. Physical examination reveals no wheezes, rales, or rhonchi with slightly decreased aeration in the left lower lung field. Mucus membranes are moist with normal skin turgor and capillary refill. Laboratory analysis reveals the following:

Na 121 mEq/L
K 3.4 mEq/L
Cl 96 mEq/L
HCO3 23 mEq/L
Cr 1.1 mg/dl
BUN 17 mg/dl

A biopsy of the responsible lesions will most likely demonstrate which of the following findings?

Question:
Laboratory analysis reveals the following:

Na 121 mEq/L
K 3.4 mEq/L
Cl 96 mEq/L
HCO3 23 mEq/L
Cr 1.1 mg/dl
BUN 17 mg/dl

A biopsy of the responsible lesions will most likely demonstrate which of the following findings?

Answer: Undifferentiated small round blue cells