USMLE Basic STD

A 23-year-old male comes to ER with five day history of diarrhea and abdominal pain. Initially, the diarrhea was watery occurring five-six times per day but yesterday he noticed blood in the stool which prompted his visit to ER. He describes his abdominal pain as colicky and severe. He also complains of nausea and decreased appetite but he has had no vomiting. His past medical history is insignificant and never had similar symptoms. He is not sexually active and he denies any illicit drug use. He has no history of recent travel. His father had colon cancer and his uncle died of liver cirrhosis. His temperature is 36.6°C (98.0°F), blood pressure is 123/82 mmHg and heart rate is 102/min. On examination, he has prominent periumbilical and right lower quadrant tenderness but no guarding or rebound. Rectal examination reveals brownish stool mixed with blood. Which of the following is the most likely diagnosis?

A 46-year-old man complains of right flank discomfort. He describes decreased urination over the last week with occasional episodes of high urine output and weakness. He is otherwise healthy. There is no family history of renal disease. On physical examination, his blood pressure is 140/90 mmHg and his heart rate is 80/min. The serum creatinine level is 2.1 mg/dl. Urinalysis shows few red blood cells, white blood cells, trace protein, and no casts. Which of the following is the most likely cause of his complaints?

A 17-year-old man comes to the emergency department and complains of intensive left flank pain that radiates to the groin. He refers to his symptom as "stone passage," which he has experienced "for so many times since childhood." His uncle has the same problem. Urinalysis shows hexagonal crystals. The urinary cyanide nitroprusside test is positive. Which of the following is the most likely cause of this patient's condition?

A 46-year-old farmer comes to the physician because of pain and swelling of his right heel. He accidentally stepped on a rusty nail while working 2 weeks ago. Although he applied over the-counter antibiotic cream locally and took acetaminophen orally, he continued to have pain at the site of the injury. He has no other medical problems and takes no medication. He has no known drug allergies. He smokes 2-3 cigarettes a day and drinks alcohol occasionally. His temperature is 38.3°C (101°F), blood pressure is 140/90 mm Hg, pulse is 84/min and respirations are 14/min. On examination, the right heel is swollen, red, and warm and tender to touch. A small puncture wound is visible. Laboratory reports show mild leukocytosis. X-ray of the right foot shows features suggestive of osteomyelitis. The most likely cause of the patient's symptoms is infection with which of the following?

A 91-year-old woman presents to the emergency department with a chief complaint of shortness of breath over the past 2 days. She has a history of hypertension and coronary artery bypass surgery 25 years earlier. Her blood pressure is 178/92 mmHg and she has jugular venous distension, hepatomegaly, and 3+ lower extremity edema. ECG is remarkable for left ventricular hypertrophy, no ST-segment elevations or depressions, no Q waves, and no T wave abnormalities. Echocardiogram reveals an ejection fraction of 60% and left atrial dilatation. There is universal left ventricular thickening. No valvular regurgitation or stenosis was noted. Which of the following underlying conditions is the most likely cause of this patient’s symptoms?

A 65-year-old man was brought to the emergency department after his wife and son were unable to wake him up this morning. His past medical history is significant for hypertension for the past 7 years. For the past year, he has had several episodes of chest pain, which was triggered by physical activity and relieved by rest. His current medications are nitrates and "baby aspirin." His blood pressure is 140/80 mm Hg, heart rate is 85/min, and respirations are 15/min. The physical examination reveals an obese man with impaired consciousness. He has a Glasgow score of 6, asymmetric pupils, and brisk deep tendon reflexes in the left extremities. Plantar stimulation provokes extension of the left great toe. The EKG shows no abnormalities. His CK-MB serum levels are within the normal range, and his LDL cholesterol level is 150 mg/dl. What is the most likely etiopathology of this patient's symptoms?

An ovarian mass removed from a 49-year-old female has yellow coloration of its cut surface. The pathologist describes it as a granulosa-theca cell tumor. Based on this pathology report, the tumor is most likely to secrete?

An 8-year-old sickle-cell patient arrives at the emergency room (ER) in respiratory distress. Over the previous several days, the child has become progressively tired and pale. The child’s hemoglobin concentration in the ER is 3.1 mg/dL. Which of the following viruses commonly causes such a clinical picture?

A 26-year-old woman comes to the physician for follow-up after a recent spontaneous abortion at 14 weeks gestation. She had one other spontaneous first trimester abortion two years ago. She has no other medical problems and does not use tobacco, alcohol or drugs. Review of systems reveals photosensitivity and occasional hematuria. On examination, you observe a bilateral malar rash. What is the most likely pathophysiology for her abortions?

A 67-year-old Caucasian male complains of progressive visual loss in his right eye over the past several months. He has a history of hypertension and type 2 diabetes mellitus. Current medications include a daily baby aspirin, hydrochlorothiazide, lisinopril, and metformin. There is no family history of visual problems. He has a 35 pack year smoking history and admits to occasional alcohol use. He is afebrile with a blood pressure of 137/82 mmHg and pulse of 73/min. Cardiac and pulmonary examinations are unremarkable. A neurologic examination demonstrates no focal motor or sensory abnormalities. The patient is asked to cover his left eye and to look at a small spot on a grid made of parallel vertical and horizontal lines. He describes the vertical lines as being bent and wavy. Which of the following is the most likely cause of this patient's complaints?

A 52-year-old female presents with a rash over her face for the past few weeks. She also complains of recent-onset difficulty with rising from a seated position and climbing stairs. On examination, you notice a dusky malar rash and a violaceous periorbital edema. Her vital signs are within normal limits. Examination shows symmetric proximal muscle weakness in legs. This patient's condition is most often associated with which of the following?

A 65-year-old Caucasian male had undergone cardiac catheterization followed by aortic valve replacement for severe aortic stenosis and coronary artery bypass grafting for three-vessel disease. His postoperative course was complicated by atrial fibrillation and a urinary tract infection. His other medical problems include hypertension, diabetes, and hypercholesterolemia. He is also receiving heparin, ciprofloxacin, and amiodarone. On postoperative day five, he developed prolonged bleeding from the venipuncture site. His labs show: Hb 11.5 g/dL, MCV88 fl, Platelet count 50,000/cmm, Leukocyte count 7,500/cmm, Segmented neutrophils 68%, Bands 1%, Eosinophils 1%, Lymphocytes 24%, Monocytes 6%, Prothrombin time 12 sec (INR=1.0), Partial thromboplastin time 65 sec. His preoperative labs were unremarkable. What is the most likely cause of these findings in this patient?

A 35-year-old Caucasian male presents to the emergency department with two episodes of bloody vomiting which occurred one-half hour ago. He has a history of migraines. For the past two days, he has been having severe headaches and has taken 20 tablets of aspirin without relief. He then resorted to heavy drinking and forgot about the pain. He drinks alcohol "occasionally" and has been smoking 1 pack of cigarettes daily for the past 18 years. Which of the following is the most likely explanation for this patient's hematemesis?

A 47-year-old man is found to have edema, ascites, and hepatosplenomegaly. The examination of his neck veins reveals elevated venous pressure with a deep y descent. Heart size on x-ray is normal. Which of the following etiologies is not a possible explanation for this syndrome?

A 36-year-old male AIDS patient comes in due to a painful red eye. He complains of pain, discharge and redness in his left eye for the past 10 days. On physical examination, you notice redness in his left eye as well as multiple skin lesions on his face, left eyelid, inner thighs, penis and pubis. The lesions are painless, pale, shiny, dome-shaped papules with a central umbilication measuring 2-5mm in diameter. These lesions were not present on his previous visit. His CD4 count thirty days ago was 100/uL. What is the most likely etiology of this patient's skin lesions?

A 60-year-old male is brought to ER by his son because he had an episode of syncope. He was watching TV in an arm-chair when suddenly lost his consciousness without any warning sign. He had several clonic jerks while unconscious. He never had such an episode before. His past medical history is significant for acute myocardial infarction six months ago and well-controlled hypertension. His current medications include captopril metoprolol hydrochlorothiazide, clopidogrel and aspirin. His blood pressure is 130/85 mmHg and heat rate is 80/min with frequent ectopic beat. Physical examination revealed mild holosystolic apical murmur radiating to the axilla. Which of the following is the most probable pathophysiologic mechanism for his syncopal episode?

A 63-year-old woman with a long history of hypertension faints after experiencing the sudden onset of severe chest pain that radiates to her back. She is rushed to the emergency room. Upon arrival she is agitated and demands quick pain relief. Her heart rate is 110/min and blood pressure is 90/50 mmHg. Jugular veins are distended. An intra-arterial catheter shows significant variation of systolic blood pressure related to the respiratory cycle. Chest x-ray reveals widening of the mediastinum. Which of the following is the most likely cause of this patient's syncope?

A 38-year-old Mexican male presents to the emergency department with a history of weight loss, fever, cough with sputum, nausea, abdominal pain, and postural dizziness for the last three months. Adrenal insufficiency is suspected, and cosyntropin (synthetic ACTH) stimulation test is performed. The rise of serum cortisol following an injection of cosyntropin is grossly subnormal. CT scan of the abdomen shows calcification of both adrenal glands. What is the most likely cause of this patient's adrenocortical insufficiency?

In a failed suicide gesture, a depressed student severs her radial nerve at the wrist. Which of the following is her expected disability?

An 18-month-old male is brought to the hospital because of fever, dyspnea, and productive cough of two days duration. His mother reports that he just recovered from prolonged diarrhea due to Giardia infection. His past medical history is also significant for pneumonia and recurrent ear infections since 6 months of age. On physical examination, his temperature is 38.7°C (101.7°F), pulse is 140/min, and respirations are 40/min. Examination reveals a young child in mild respiratory distress and bronchial breath sounds in the right lower lung lobe. Which of the following is the most likely cause of his recurrent infections?

The parents of a 2-year-old bring her to the emergency center after she had a seizure. Although the parents report she was in a good state of health, the vital signs in the emergency center reveal a temperature of 39C (102.2F). She is now running around the room. Which part of the story would suggest the best outcome in this condition?

A 3-year-old male is brought to the emergency department for evaluation of right neck swelling. His parents noticed a lump on his right neck yesterday, which has since increased in size and is now erythematous and tender. He has been previously healthy except for mild upper respiratory tract symptoms last week. His temperature is 38C (100.4F), pulse is 90/min, and respiratory rate is 25/min. On examination, he is nontoxic appearing. A 5-cm anterior cervical lymph node is palpated on the right side. It is poorly mobile, warm, erythematous, and tender to palpation. There is no fluctuance or induration. What is the most likely organism causing these symptoms?

A 4-week-old boy is brought to clinic by his mother because of a 1 day history of labored breathing. His birth was uneventful and immunizations have been up to date. His mother reports that the patient developed conjunctivitis on the fourth day of life. On physical examination, he is breathing rapidly at 40 breaths per minute and is afebrile. His chest reveals bilateral inspiratory crackles and a slight wheeze. On chest x-ray, bilateral pneumonia is evident. The leukocyte count is elevated at 15,000 with 40% eosinophils. Which of the following is the most likely pathogen causing the patient's symptoms?

A pregnant 35-year-old patient is at highest risk for the concurrent development of which of the following malignancies?

A 45-year-old woman is seen with wasting of the intrinsic muscles of the hand, weakness, and pain in the wrist. Which of the following nerves has most likely been injured?

A 2-year-old girl presents with fever of 39.3 C and irritability. She has had an upper respiratory tract infection for 4 days. On examination, the right ear is bulging and has poor movement on insufflation. Which of the following organisms is most likely responsible for these findings?

A 27-year-old basketball player jumps to block a shot with his right hand. As his hand contacts the ball, he feels severe pain in his right shoulder. He presents to the emergency department with continuing shoulder pain. You note that he holds his right arm in slight external rotation, supporting its weight with his left hand. On physical examination, he resists internal rotation of his right arm. Which of the following nerves is most likely to be injured in this patient?

A 55-year-old Asian man with mitral stenosis secondary to rheumatic heart disease undergoes dental surgery for caries. Postoperatively, he does well and is discharged home. Two weeks later, he presents with fever, chills, fatigue, and feels "sick." Four out of four blood culture bottles are positive for gram-positive cocci. An echocardiogram is performed and shows mitral valve vegetations. Which of the following is the most likely causative organism of this patient's condition?

A 67-year-old woman is being evaluated for periodic confusion, insomnia, and frequent falls as well as episodes of decreased alertness and visual hallucinations. On physical examination, she has increased lower extremity muscle tone but downgoing Babinski reflexes bilaterally. Which of the following pathologic findings most likely underlies her condition?

A 3-year-old boy is brought to the office by his parents for the evaluation of dry eyes and photophobia. He has some difficulty in adapting to darkness. He is a very poor eater, and his diet consists mainly of canned foods, and very rarely, fresh vegetables or milk. Examination reveals dry, scaly skin, follicular hyperkeratosis in the extensor surfaces of the extremities, and dry, silver-gray plaques on the bulbar conjunctiva. What is the most likely diagnosis of this patient?

A 3-month-old Jewish infant is brought to the emergency department because of a generalized seizure 1 hour ago. He is lethargic, weighs 2.7kg (61b), and has a doll-like face with fat cheeks, relatively thin extremities, and a protuberant abdomen. His liver is felt 5cm (2in) below the right costal margin. His kidneys are enlarged. His blood sugar level is 40mg/dl. His serum uric acid, total cholesterol, triglycerides and lactic acid levels are elevated. The levels of his liver transaminases are normal. What is the most likely cause of this infant's symptoms?

A 3-year-old boy is brought by his father to the Emergency Department with fever, headache and neck pain that developed over the past several hours. The father states he is not the birth father, and that he and his wife adopted the boy at 18 months of age after his birth mother abandoned him. Physical examination reveals a lethargic male with a temperature of 39.7 C (103.5 F). There is photophobia, and mildly injected conjunctiva are appreciated. Pupils are equal and reactive and funduscopic examination is unremarkable. The patient has neck stiffness with a positive Kernig's sign. A complete blood count reveals a leukocyte count of 24,000/mm3 with 64 segmented neutrophils and 25 bands. A lumbar puncture is performed that reveals elevated CSF pressure, decreased glucose, and elevated protein. A Gram's stain shows gram-negative pleomorphic rods. There is no growth on blood agar. Growth on chocolate agar reveals white colonies. Which of the following is the most likely pathogen?

In an amenorrheic patient who has had pituitary ablation for a craniopharyngioma, which of the following regimens is most likely to result in an ovulatory cycle?

A newborn is noted to be quite jaundiced at 3 days of life. Laboratory data demonstrate his total bilirubin to be 17.8 mg/dL (direct bilirubin is 0.3 mg/dL). Which of the following factors is associated with an increased risk of neurologic damage in a jaundiced newborn?

A 22-year-old college student went to the health clinic complaining of a fever over the last 5 days, fatigue, myalgias, and a bout of vomiting and diarrhea. The clinic doctor diagnosed him with acute gastroenteritis and told him to drink more fluids. Three days later, the student presents to the ED complaining of substernal chest pain that is constant. He also feels short of breath. His temperature is 100.9°F, HR is 119 beats per minute, BP is 120/75 mmHg, and RR is 18 breaths per minute. An ECG is performed revealing sinus tachycardia. A chest radiograph is unremarkable. Laboratory tests are normal except for slightly elevated WBCs. Which of the following is the most common cause of this patient’s diagnosis?

A previously healthy 6-year-old girl is brought to the office due to a 10-day history of persistent, thick, nasal discharge, nasal congestion, cough, and intermittent low-grade fever. She has had no vomiting, headache, earache, or rash. Her temperature is 37.2 C (98.9 F), blood pressure is 88/50 mmHg, pulse is 90/min, and respirations are 15/min. Physical examination shows clear tympanic membranes, congested posterior nasopharynx with thick, yellow and purulent mucus, and red, swollen nasal turbinates. Transillumination of the sinuses is equivocal. Palpation of the maxillary sinuses shows mild tenderness. Lungs are clearto auscultation. Which of the following organisms is the most common etiologic agent of this condition?

A 65-year-old female complains of difficulty eating over the last two days. She states that food drops out of her mouth. She has also been having some discharge in her left ear recently. She denies any sore throat, nasal discharge, chest pain, cough, or difficulty breathing. Her past medical history is significant for type 2 diabetes mellitus, hypertension, and hyperlipidemia. She has been poorly complaint with follow-up appointments. Her temperature is 38.8°C (101.7°F), pulse is 96/min, blood pressure is 140/90 mmHg, and respirations are 18/min. Examination of the left ear canal shows granulations. There is facial asymmetry, and the angle of the mouth on the left is deviated downward. Which of the following is the most likely causative organism for this patient's condition?

A 58-year-old man presents with a one-year history of diarrhea. The stools are watery and accompanied by abdominal cramps. He denies any fever, blood per rectum, or foul-smelling stools. He has also experienced frequent episodes of dizziness, flushing, wheezing, and a feeling of warmth. He has taken herbal medicines, which failed to relieve his symptoms. He is depressed about his illness, and feels hopeless about diagnosis and treatment. He appears ill. Auscultation of the chest shows a 2/6 systolic murmur over the left lower sternal border. Abdominal examination shows hepatomegaly 3cm below the right costal margin, mild shifting dullness, and no abdominal tenderness. Laboratory studies show: Hb 13.0gm/dl, MCV 90fl, WBC 6,100/cmm, Platelets 210,000/cmm, AST101 U/L, ALT 99 U/L, Alkaline phosphatase 400 mg/dl. This patient is at risk of developing a deficiency of which vitamin or mineral?

A 42-year-old woman is evaluated for chronic abdominal pain and fatigue. Her pain is epigastric, crampy, and sometimes awakens her from sleep. She denies any recent weight loss, nausea, or vomiting. Her diet consists mainly of fruits and vegetables. She also complains of a "strange appetite" for paper and ice that she has never had before. Upper gastrointestinal endoscopy reveals an ulcer located on the anterior wall of the duodenal bulb. Her unusual appetite is most directly related to:

A 45-year-old man presents to the emergency room with a two-day history of fever, dyspnea, abdominal pain, and diarrhea. He has no chest pain, but complains of dry cough. His past medical history is significant for bone marrow transplantation for acute myeloid leukemia (AML) three months ago. His temperature is 39°C (102.2°F), blood pressure is 122/80 mm Hg, pulse is 98/min, and respirations are 22/min. Exam of the oropharynx reveals thrush. Lungs exam demonstrates bilateral diffuse rales. Heart sounds are regular. Nonspecific abdominal tenderness is present. The chest radiograph shows multifocal, diffuse patchy infiltrates. Which of the following is the most likely cause of this patient's current condition?

A 1-day-old infant appears dusky in the newborn nursery during feeding. Oxygen is immediately administered by nasal cannula. Shortly afterward, she develops tachypnea. On physical examination, her blood pressure from the right upper arm is 50/30 mm Hg, her pulse is 180/min, and her respirations are 60/min. An echocardiogram is consistent with hypoplastic left heart syndrome. Which of the following would likely be found on auscultation?

A 45-year-old Caucasian male presents with a 2-year history of progressive heartburn which is most severe while supine. Over-the-counter antacids have not relieved his symptoms. Endoscopy shows a hiatal hernia. The patient is reluctant to accept any treatment. Which of the following is he at risk for if his condition is left untreated?

Two new mothers are discussing their infants outside the neonatal intensive care unit. Both were born at 36 weeks’ gestation. One infant weighs 2600 g (5 lb, 12 oz) while the other infant weighs 1600 g (3 lb, 8 oz). The mother of the second infant should be told that her child is more likely to have which of the following conditions?

A 12-year-old boy is brought to the emergency department because of severe pain near his left knee. He has sickle cell disease, and has been hospitalized previously for sickle cell crisis. Vital signs are notable for mild fever. Examination of the left lower extremity reveals a normal knee joint with marked tenderness and swelling over the proximal tibia. Labs show leukocytosis and elevated ESR. He is subsequently diagnosed with osteomyelitis. Which of the following organisms is the most likely cause of his condition?

A 7-year-old boy presents with tenderness and erythema of one knee joint. He has had troubles with infections since about 3 months of age. A brother and a maternal uncle both died of infectious disease at an early age. A detailed immunologic evaluation performed at 2 years of age demonstrated plasma IgG less than 50 mg/100 mL. Normal numbers of circulating T cells and normal cellular immunity were found. The boy had been treated monthly since then with IV immunoglobulin. This therapy had markedly reduced, but not eliminated, the boy's infection rate. Which of the following is the most likely pathogen to cause infectious arthritis in this patient?

A 55-year-old woman is in the intensive care unit on a ventilator for hypoxemia following “flash” pulmonary edema. Her PO2 on the blood gas prior to intubation was 44 mm Hg, and now while breathing 100% oxygen on the ventilator her repeat blood gas reveals a PO2 of 80 mm Hg. Hypoxemia while receiving 100% oxygen indicates which of the following problems?

A 6-year-old Caucasian boy is hospitalized for acute sinusitis that was accompanied with intensive nasal bleeding. Past medical history is significant for recurrent pulmonary infections and several hospitalizations for parenteral antibiotic therapy. The sweat chloride test is positive. The blood tests reveal a prothrombin time (PT) of 20 seconds. Which of the following coagulation factors is most likely to be deficient in this patient?

A 20-year-old Caucasian male presents with lower abdominal pain for the past few hours. The pain first started around the umbilicus, but then shifted to the right lower abdominal area. He has had one episode of vomiting. Physical examination shows tenderness at McBurney's point. CT scan of the abdomen confirms the diagnosis of acute appendicitis. Which of the following explains the pathophysiology of the shifting of pain from the peri-umbilical area to the right lower quadrant in acute appendicitis?

A 59-year-old female is hospitalized due to lower gastrointestinal bleeding. Her past medical history includes diabetes mellitus, hypertension, chronic obstructive pulmonary disease, cor pulmonale and recurrent urinary tract infections. Her condition initially stabilized with fluid resuscitation and blood transfusions, but she subsequently developed an acute renal failure. Her urine output has been between 300 and 400 ml per day for the last couple of days. On the 10th day of her hospitalization she is lethargic. Serum analysis reveals: Hemoglobin 10.2 g/dl, Hematocrit 30%, WBC 14,300/mm3, Blood glucose 93 mg/dl, BUN 141 mg/dl, Creatinine 4.1 mg/dl, Sodium 133 mEq/L, Potassium 5.0 mEq/L, pH 7.15, pO2 90 mmHg, pCO2 60 mmHg, HCO3 18 mEq/L. Which of the following is the most likely cause of her lethargy?

A 32-year-old male complains of progressive weakness and exertional dyspnea. His past medical history is significant for a knife injury to the right thigh two months ago. He has been arrested several times for robbery. He consumes alcohol regularly, and smokes crack occasionally. His younger brother died of cystic fibrosis. His blood pressure is 160/60 mmHg, and heart rate is 100/min. His extremities are warm and flushed. Carotid upstroke is brisk. The point of maximal impulse is displaced to the left, and a soft, holosystolic murmur is heard over the cardiac apex. The murmur does not change with the Valsalva maneuver. Which of the following is the most likely cause of this patient's symptoms?

A 32-year-old woman presents with progressively worsening dyspnea on exertion one month after returning from a vacation in Texas. She says that her symptoms have progressed to the point that she now wakes during the night with a choking sensation that improves only with sitting up. Recently her shortness of breath has required her to significantly limit her physical activity. She denies having associated chest pain, skin rash or joint pain. She has no significant past medical history. Family history is significant for thyroid cancer in her aunt and lung cancer in her father, a heavy smoker. On physical examination, her temperature is 37.2°C (99°F), pulse is 96/min, blood pressure is 110/70 mmHg, and respirations are 14/min. Bilateral pitting ankle edema is present. Her liver is enlarged 2 cm below the right costal marginal. Lung auscultation reveals decreased breath sounds at the bilateral bases. Cardiac exam reveals the presence of a third heat sound. Chest x ray shows an enlarged cardiac silhouette and small bilateral pleural effusion. EKG is unremarkable. Which of the following is the most likely cause of her symptoms?

A 55-year-old homeless man presents to the emergency room complaining of muscle cramps and perioral numbing. The patient looks malnourished. He says that he consumed a lot of alcohol recently. His past medical history is significant for chronic and recurrent abdominal pain for which he was advised to quit drinking alcohol. His temperature is 36.7°C (98°F), blood pressure is 110/65 mmHg, pulse is 80/min, and respirations are 18/min. The laboratory values are: Hemoglobin 7.2 g/dl, MCV 105 fl, Leukocyte count 9,000/cmm, Platelets 200,000/cmm, ESR 20 mm/hr, Serum sodium 145 mEq/L, Serum potassium 4.0 mEq/L, Serum calcium 6.8 mg/dl, Serum phosphorus 2.5 mg/dl. What is the most probable cause of hypocalcemia observed in this patient?

A 51 -year-old man complains of difficulty walking and mild right-sided foot pain for the past several weeks. His medical history is significant for type 1 diabetes mellitus, hypertension and hypercholesterolemia. Physical examination reveals a significantly deformed right foot and a mildly deformed left foot. X-rays suggest effusions in several of the tarsometatarsal joints, large osteophytes, and several extra articular bone fragments. Which of the following is the most likely cause of this patient's complaints?

A 67-year-old woman is currently postoperative day 8 after an emergent laparoscopic cholecystectomy for acute cholecystitis. On postoperative day 2 she spiked a temperature of 40°C (101.4°F) and began to complain of some shortness of breath. X-ray of the chest revealed right lower lobe pneumonia, and the patient was started on clindamycin. Today she is experiencing multiple episodes of foul-smelling, watery diarrhea that is green tinged but non-bloody. She also complains of lower abdominal cramping. Her temperature is 37.8°C (100°F), pulse is 90/min, respiratory rate is 15/min, and blood pressure is 110/70 mm Hg. Which of the following is the most likely explanation for these findings?

A 7 -year-old boy is rushed to the emergency department after falling on his outstretched hand. He immediately complained of right arm pain after the accident, and he currently cannot move his arm due to the pain. He is crying and holding his right arm in flexion. There is ecchymosis just above his elbow. He cries out in pain when his arm is moved. An x-ray reveals a supracondylar fracture. What secondary injury is most commonly associated with this patient's fracture?

A 12-year-old African American boy is brought to the office due to a 2-day history of high-grade fever and chills. He was apparently well before the onset of fever. He has no bone pain. He has sickle cell disease and has had 4 hospitalizations for painful crises and one episode of osteomyelitis. His blood pressure is 90/60 mm Hg, pulse is 100/min, respirations are 22/min and temperature is 38.9 C (102F). He appears drowsy. His laboratory report shows a total WBC count of 16,000/mm3 with 12% bands and Hb of 9.0 g/dl. Which of the following is the most likely cause of this patient's condition?

A 10-year-old boy is admitted to the hospital because of bleeding. Pertinent laboratory findings include a platelet count of 50,000/µL, prothrombin time (PT) of 15 seconds (control 11.5 seconds), activated partial thromboplastin time (aPTT) of 51 seconds (control 36 seconds), thrombin time (TT) of 13.7 seconds (control 10.5 seconds), and factor VIII level of 14% (normal 38%-178%). Which of the following is the most likely cause of his bleeding?

A 72-year-old woman complains of fatigue, dyspepsia, and shortness of breath. Her daughter tells you that her mother also has some slight memory loss and occasionally complains of numbness in her legs. The laboratory tests you ordered show a hemoglobin of 10.2 g/dL and an MCV of 110. The most likely cause is:

A 65-year-old man complains of lower leg swelling, fatigue and poor appetite. His past medical history is significant for recurrent chest infections, wheezing, cough, recent pyelonephritis, and arterial hypertension. He smokes 1 pack of cigarettes a day but denies alcohol or intravenous drug use. His physical examination reveals a barrel-shaped chest with bilateral scattered wheezes. His abdomen is distended and his liver edge is palpated 4 cm below the right costal margin. You note pitting edema and dilated, tortuous, superficial veins over the bilateral lower extremities. Manual pressure on the abdomen causes persistent distention of the jugular veins. The patient's serum sodium level is 135 mEq/L and his creatinine concentration is 1.2 mg/dl. An abnormality of which of the following is most likely to explain his edema?

A previously well 28-year-old female has developed gradual onset of fever and malaise over 2–3 weeks. She also complains of arthralgias and myalgias. Repeated measurement of her temperature reveals a low grade fever between 38°C and 39°C. Physical examination reveals an oval retinal hemorrhage with a clear, pale center; a pansystolic cardiac murmur heard best at the apex; and small, tender nodules on her fingertips. Which of the following is the most likely causative organism?

A 52-year-old alcoholic man presents to the emergency department because of anxiety and tremors. His last drink of alcohol was 2 days ago. His initial electrolyte panel is: Sodium 132 mEq/L, Potassium 2.9 mEq/L, Chloride 100 mEq/L, Bicarbonate 25 mEq/L. He is treated for alcohol withdrawal, and given aggressive intravenous and oral potassium supplementation. Three days later, his electrolyte panel is: Sodium 135 mEq/L, Potassium 3.1 mEq/L, Chloride 102 mEq/L, Bicarbonate 28 mEq/L. Which of the following explains why this patient's potassium level is so difficult to correct?

A 21-year-old woman presents to the ED complaining of diarrhea, abdominal cramps, fever, anorexia, and weight loss for 3 days. Her BP is 127/75 mm Hg, HR is 91 beats per minute, and temperature is 100.8°F. Her abdomen is soft and nontender without rebound or guarding. WBC is 9200/μL, β-hCG is negative, urinalysis is unremarkable, and stool is guaiac positive. She tells you that she has had this similar presentation four times over the past 2 months. Which of the following extraintestinal manifestations is associated with Crohn disease but not ulcerative colitis?

A 16-day-old infant presents with fever, irritability, poor feeding, and a bulging fontanelle. Spinal fluid demonstrates gram-positive cocci. Which of the following is the most likely diagnosis?

A 48-year-old Caucasian male presents to your office complaining of progressive exertional dyspnea. It has become especially bothersome over the past two months. Presently, he becomes short of breath after climbing one flight of stairs. He denies any significant problems in the past. He is not taking any medications and he denies smoking or drinking alcohol. His temperature is 37.2°C (98.9°F), pulse is 78/min, blood pressure is 130/75 mmHg and respirations are 14/min. Chest examination reveals a harsh systolic murmur that is best heard at the right second intercostal space with radiation along the carotid arteries. An S4 is heard at the apex. Based on these findings, what is the most likely cause of this patient's symptoms?

A 65-year-old woman presents to your office for evaluation of genital prolapse. She has a history of chronic hypertension, well controlled with a calcium channel blocker. She has had three full-term spontaneous vaginal deliveries. The last baby weighed 9 lb and required forceps to deliver the head. She says she had a large tear in the vagina involving the rectum during the last delivery. She has a history of chronic constipation and often uses a laxative to help her have a bowel movement. She has smoked for more than 30 years and has a smoker’s cough. She entered menopause at age 52 but has never taken hormone replacement therapy. Which of the following factors is least important in the subsequent development of genital prolapse in this patient?

A 56-year-old male with a long history of diabetes mellitus complains of nocturnal urinary frequency, occasional dribbling and difficulty completing his stream. His past medical history is significant for a myocardial infarction two years ago and moderately decreased visual acuity. On physical examination, his blood pressure is 160/100 mmHg and his heart rate is 70/min. There is a carotid bruit auscultated on the left side as well as trace ankle edema. Post-void bladder catheterization yields 60 ml of urine. Dipstick urinalysis reveals 2+ protein and 3-4 WBC/hpf. The patient's serum creatinine level is 2.4 mg/dl. Which of the following is the most likely cause of his renal dysfunction?

A 53-year-old man comes to the office because of difficulty reading fine print over the last year. He now has to hold books, menus, and magazines at an arm’s length in order to read them. He has never had visual problems before. Which of the following is most likely abnormal in this patient?

You ask a patient to call your office during her next menstrual cycle to schedule a hysterosalpingogram as part of her infertility evaluation. Which day of the menstrual cycle is best for performing the hysterosalpingogram?

A 3-month-old male infant is brought to the emergency department by his mother because of difficulty in breathing. His mother was admitted in the hospital ten days ago due to a urinary tract infection, and he was cared for by his grandmother during that period. His mother had just been discharged from the hospital yesterday, and noticed that he was constipated and having difficulty with breastfeeding. On examination, he is afebrile. His pulse rate is 110/min, respirations are 36/min with shallow breathing efforts, and blood pressure is 90/50mm Hg. His weight is at the 35th percentile. Examination shows ptosis, dilated pupils with sluggish reaction to light, diminished deep tendon reflexes and decreased muscle tone. What is the most likely mechanism of his illness?

A 34-year-old obese Caucasian female complains of periodic visual obscurations. She has episodes during which she "goes blind" for several seconds when standing up or stooping forward abruptly. She also describes frequent morning headaches over the last two months for which she has had to take ibuprofen or aspirin almost every morning. She takes no other medications. Past medical history is insignificant aside from one uncomplicated vaginal delivery. She denies use of alcohol, tobacco, or illicit drugs. She is afebrile with a blood pressure of 138/88 mmHg and pulse of 93/min. Visual field testing shows enlarged blind spots. There are no other significant findings on neurologic examination. Which of the following is the most likely cause of this patient's symptoms?

A 16-year-old African American male with sickle cell anemia presents complaining of a 1-week history of exertional dyspnea, fatigue, and generalized weakness. He denies fevers, chills, night sweats, or cough. His only medication is oxycodone for chronic pain. On physical examination, he weighs 68 kg (150 lbs) and is 168cm (66 in) tall His temperature is 36.7C (98F), blood pressure is 120/70 mm Hg, pulse is 76/min, and respirations are 18/min. All organ systems appear normal Laboratory studies show: Hematocrit 20%, Mean corpuscular volume 110 fl, Reticulocyte count 1.0%. Which of the following is the most likely mechanism underlying these findings?

Prolonged unopposed estrogen stimulation in an adult woman increases the risk of development of endometrial hyperplasia and subsequent carcinoma. Which of the following is the most common histologic appearance for this type of cancer?

A 2-week-old infant presents with hepatosplenomegaly and a thick, purulent, bloody nasal discharge. Coppery, oval, maculopapular skin lesions are present in an acral distribution. The neurologic examination is normal, including head circumference. Which of the following is the most likely cause of this congenital infection?

A 53-year-old homosexual man comes to the ER with shortness of breath and dry cough over the past week. You note that he was hospitalized for Candida esophagitis one month ago, but left against medical advice. On physical examination, his blood pressure is 120/70 mmHg, heart rate is 120/min and regular, oxygen saturation is 89% on 2L/min of oxygen by nasal cannula, and temperature is 38.3°C (101°F). There are extensive white plaques over the oral mucosa and there is a soft 2/6 systolic murmur over the cardiac apex. Lung auscultation is remarkable for faint bilateral crackles. Which of the following is most likely responsible?

A 9-year-old boy is brought to the office by his mother because of itching, burning and oozing skin lesions on both of his legs. The boy appears tanned. When asked if he had been spending time outdoors, he replies with great excitement that he just returned yesterday from a camping trip in the woods with his dad. Physical examination of both lower limbs reveals vesicles with erythema arranged in a linear fashion. Weepy and crusted lesions and edema are also present. What type of reaction is responsible for this boy's lesions?

A 42-year-old morbidly obese man is being evaluated for poor sleep. He complains of frequent awakenings due to a choking sensation and says that the resulting tiredness severely limits his physical activity. He also complains of chronic leg swelling. He denies cigarette, alcohol, or drug use. On physical examination, his blood pressure is 160/100 mmHg and his heart rate is 110/min. Which of the following additional findings is most likely to be present in this patient?

A 6-week-old child arrives with a complaint of “breathing fast” and a cough. On examination you note the child to have no temperature elevation, a respiratory rate of 65 breaths per minute, and her oxygen saturation to be 94%. Physical examination also is significant for rales and rhonchi. The past medical history for the child is positive for an eye discharge at 3 weeks of age, which was treated with a topical antibiotic drug. Which of the following organisms is the most likely cause of this child’s condition?

A 40-year-old male patient presents with a thyroid nodule. His other complaints are episodes of palpitations, anxiety and sweating. He denies heat intolerance. His weight and appetite are normal. He has a family history of thyroid cancer. His pulse is 80/min, and blood pressure is 160/100 mmHg. Examination of the neck shows a 4-cm, hard, non-tender thyroid nodule. The urinalysis, serum sodium, serum potassium, serum calcium, serum creatinine, serum PTH, TSH, T3 and T 4 levels, and the EKG are all normal. The serum calcitonin level is elevated. The urinary levels of metanephrine and norepinephrine are increased as well. FNA biopsy of the thyroid nodule shows malignant cells. Genetic testing shows a mutation in the RETproto oncogene. Which of the following abnormalities is also present in most patients suffering from this disorder? Select one:

You are called to the nursery to evaluate a newborn infant. The mother is a 24-year-old primigravida. Her pregnancy was complicated by preeclampsia. The infant was delivered at 39-weeks’ gestation via emergent cesarean section due to maternal hypertension and non-reassuring fetal heart tones. On examination, the infant's weight is 2.6 kg (5 lb 11 oz) placing him in the 5th percentile, height is 18 inches (46 em) placing him in the 5th percentile, and head circumference is 13 inches (33 cm) placing him in the 1oth percentile. The infant's head seems large for her body. There is a paucity of subcutaneous fat. The remainder of the physical examination is unremarkable. This infant is at risk for developing which of the following?

A 3-week-old African American boy is brought to the Emergency Department because of a generalized seizure 2 hours ago. The infant is highly irritable with incessant high pitched crying. The infant's weight is 2.5 kg (250 gm below birth weight), blood pressure is 70 /40 mm Hg, pulse is 145/min and respirations are 50/min. Laboratory results show: Blood glucose 120 mg/dL, Urea nitrogen 50 mg/dL, Serum sodium 170 mEq/L, Serum calcium 8.5 mg/dL, Serum magnesium 1.5 mg/dL. Which of the following is the most likely cause of this infant’s seizure?

A 60-year-old woman recently diagnosed with type 2 DM complains of daily headaches and double vision that have gradually worsened over the previous month. An MRI shows a large pituitary adenoma. Which of the following is most likely being secreted by this tumor?

A mother brings her 3-year-old son to the pediatrician because he has had 7 days of fever and a painful swollen lymph node in his right groin. This is the boy's sixth episode of lymph node swelling; previous episodes resolved after drainage and prolonged antibiotic therapy. The child also has a past medical history significant for pneumonia at 12 months of age that required chest tube placement for drainage. His maternal uncle died in childhood from recurrent infections. On examination, the boy is at the 5th percentile for both height and weight His temperature is 38.5 c (101.3 F). There is an enlarged, tender lymph node in the right inguinal area with erythema and warmth of the overlying skin. There are several healed incisions in the inguinal regions bilaterally, as well as around the neck from old drainage sites. Laboratory analyses reveal the following: Hematocrit 35%, Platelet count 350,000/mm3, Leukocyte count 17000/mm3, Segmented neutrophils 65%, Bands 10%, Lymphocytes 25%. Gram stain of fluid aspirated from the affected lymph node reveals numerous bacteria-filled segmented neutrophils. Cultures grow S. aureus. What is the most likely mechanism underlying these findings?

A 57-year-old man has end-stage heart failure due to atherosclerosis. His cardiologist refers him for evaluation for heart transplantation. Which of the following is an absolute contraindication for heart transplantation?

A 57-year-old male is hospitalized for hyponatremia. Physical examination reveals no signs of fluid overload. Serum analysis reveals a sodium concentration of 125mEq/1, glucose level of 128mg/dl, BUN of 8mg/dl, and creatinine of 0.7mg/dl. The urine osmolarity is 330mOsm/l and urine sodium concentration is 45mEq/1. After a 2L normal saline infusion, the serum sodium is 126mEq/1 and the urine sodium excretion is increased to 90 mEq/1. Which of the following is the most likely cause of this patient's hyponatremia?