CK- NBME 11 – Block 1

A 1-week-old boy is brought to the physician because of a 2-day history of fever and irritability. His temperature is 39°C (102.2°F). Examination shows decreased motion of the left hip with tenderness. An x-ray of the hip shows increased joint space. Aspiration of the hip joint yields 3 mL of purulent fluid. A culture of the fluid is most likely to grow which of the following organisms?

 A 27-year-old man with schizophrenia is brought to the emergency department by his mother because he says he has been unable to see anything for the past 3 hours. They have been on a car trip across the country for the past 6 days. Last night, he reported hearing voices, so they stopped in an emergency department by the highway; he was administered haloperidol and was released 1 hour later. He has no other history of serious illness. His only regularly scheduled medication is intramuscular fluphenazine every 3 weeks. His temperature is 37.1°C (98.8°F), pulse is 88/min, and blood pressure is 142/78 mm Hg. On examination, he is lying on a stretcher, moaning, with his upper extremities held rigidly to his side. The eyes are rotated superiorly. The neck is rigid. On mental status examination, he is alert but too distressed to answer questions. His leukocyte count is 9800/mm3. Which of the following is the most likely cause of this patient’s current visual problems?

 A 32-year-old man comes to the physician with his wife because of changes in his behavior during the past 2 weeks. Four weeks ago, he witnessed a close friend die in a motor vehicle collision. On the evening of the collision, the patient had offered to drive his friend home after they had had a few beers, but the friend declined. As the friend walked away from the patient’s car, he was struck by an oncoming vehicle. The patient states that he does not remember much about the incident. During the past 2 weeks, his wife reports that he has been awakening nightly in a sweat and shouting “Watch out!” She states that he has been more emotionally distant and that he has not wanted to socialize with friends. He has not driven his car for 10 days. The patient reports difficulty sleeping and concentrating and says that “things just don’t seem real at times.” He says he used to drink alcohol only rarely but has been drinking two beers nightly for 3 weeks to help him calm his mind and sleep. His temperature is 36.9°C (98.4°F), pulse is 82/min, respirations are 12/min, and blood pressure is 145/80 mm Hg. Physical examination shows no abnormalities. On mental status examination, he has a flat affect but is irritable. He says that he has not been feeling much of anything lately. He has thought about death frequently during the past 2 weeks but says he does not want to commit suicide. Results of laboratory studies are within the reference range. Which of the following is the most likely diagnosis?

A 12-year-old boy is brought to the physician because of a 1-year history of recurrent episodes of increased urinary urgency and frequency, increased thirst, and bed wetting. The episodes occur every 3 to 4 weeks and last 2 to 3 days; he does not wet the bed between episodes. He has not had abdominal pain or a burning sensation on urination. He was toilet trained at the age of 3 years and had not wet the bed since the age of 4 years. He has no history of serious illness and takes no medications. His parents divorced 1 year ago; his mother is the custodial parent, and he visits his father on occasional weekends. He is at the 50th percentile for height, at the 95th percentile for weight, and above the 95th percentile for BMI. Genital and pubic hair development are Tanner stage 1. Laboratory studies show:

Serum glucose:

85 mg/dL

Urine (first morning void):

Specific gravity: 1.015

Blood: negative

Glucose: negative

Protein: negative

Which of the following is the most likely diagnosis?

 A 17-month-old infant with sickle cell disease has a 1-day history of rectal temperatures to 40.6°C (105°F). He has had rhinorrhea and a cough for 3 days. He receives daily penicillin prophylaxis and has received all appropriate immunizations. He is slightly irritable and has clear rhinorrhea. His spleen is palpable 2 cm below the left costal margin. The remainder of the examination is normal. Laboratory studies show:

Hemoglobin: 9.8 g/dL

Leukocytes: 18,700/mm³

Segmented neutrophils: 65%

Lymphocytes: 30%

Bands: 3%

Monocytes: 2%

Which of the following is the most appropriate pharmacotherapy for this patient?

A 32-year-old primigravid woman at 27 weeks’ gestation is brought to the emergency department because of painless vaginal bleeding for 6 hours. She has to change sanitary pads every 2 hours. She has had no prenatal care. Ultrasonography at 16 weeks’ gestation showed a normal fetus and a posterior fundal placenta. Her pulse is 100/min, and blood pressure is 120/80 mm Hg. Pelvic examination shows normal external genitalia. The uterus measures 27 cm and is nontender. Speculum examination shows a 2-cm friable ulcer on the cervix. The cervix is long, the external os is 1 cm dilated, and the internal os is closed. Which of the following is the most likely cause of the bleeding?

 A 17-year-old girl is brought to the emergency department by her father after she had loss of consciousness and collapsed on the sidewalk during an afternoon run. Her father says that his daughter is overweight and has been trying to lose weight for the past 2 months. In addition to modifying her diet, she has been running 2 to 3 miles daily during the past month. She has no history of serious illness and takes no medications. On questioning, her father says that his daughter is a “good kid” but occasionally attends parties, where alcohol is served; he is unsure whether she has used illicit drugs. On arrival, she is somnolent but arousable and responsive. She is oriented to person but not to place or time. She is 168 cm (5 ft 6 in) tall and weighs 85 kg (187 lb); BMI is 30 kg/m2. Her temperature is 39°C (102.2°F), pulse is 140/min, respirations are 40/min, and blood pressure is 105/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 97%. Examination shows cool, clammy, dry skin. The pupils are equal and reactive to light. No other abnormalities are noted. Which of the following is the most likely diagnosis?

A 72-year-old man is brought to the emergency department 2 hours after a generalized tonic-clonic seizure that lasted 5 minutes. He has no other history of seizures. His wife reports that the patient has been increasingly forgetful during the past 3 months. He also has had increasingly frequent jerk-like movements of the arms and legs. Three times during the past week, he did not recognize his wife when he saw her enter a room, but he recognized her voice. He has hypercholesterolemia treated with atorvastatin. He drinks three to four beers nightly. Examination shows involuntary jerking of the head, trunk, and all extremities. There are fasciculations of all extremities. On mental status examination, he has a normal mood and affect. He is alert and is able to repeat six digits forward. He recalls two of five parts of a name and address after 5 minutes. When shown a sketch of a pretzel, he identifies it as a snake. Which of the following is the most likely diagnosis?

 A 37-year-old woman comes to the physician for a second opinion regarding a positive Chlamydia trachomatis DNA hybridization test done by her primary physician 2 weeks ago. The patient has been in a mutually monogamous heterosexual relationship for the past 7 years. She does not doubt her partner’s fidelity, and she disbelieves the results. She has no history of serious illness and takes no medications. Pelvic examination shows normal vaginal discharge, an IUD string at the cervical os, and normal cervical mucus. There is no pelvic tenderness. The physician is aware that the prevalence of C. trachomatis infection in this patient’s age group is less than 1%; the sensitivity of the test is 80%, and the specificity is 97%. Which of the following best explains the validity of the test results to this patient?

 A 7-month-old girl is brought to the physician because of a 2-day history of rapid breathing, sweating, pallor, decreased feeding, and increased fussiness. The mother says the patient had the same symptoms 3 weeks ago, but they were less severe and resolved spontaneously in less than 1 day. The patient is alert and fussy. She is at the 50th percentile for length and weight. Her temperature is 37.3°C (99.1 °F), pulse is 220/min, respirations are 48/min, and blood pressure is 62/42 mm Hg. Capillary refill time is 3 seconds. Examination shows pink skin. The liver edge is palpated 3 cm below the right costal margin. The remainder of the examination shows no abnormalities. An ECG shows narrow complex tachycardia. Which of the following is the most appropriate next step in management?

 A 67-year-old woman is brought to the physician because of a 2-week history of increasingly blurred vision. Two months ago, she was hospitalized for 10 days for management of tuberculous meningitis; treatment with ethambutol, isoniazid, prednisone, pyrazinamide, pyridoxine, and rifampin was started at that time. She had been feeling well since discharge. Her only other medication is lisinopril for hypertension. She has no other history of serious illness. Her blood pressure is 125/70 mm Hg. Examination shows a best- corrected visual acuity of 20/50 bilaterally. Visual field examination shows decreased vision in the center of each field. Peripheral vision is normal. A mild-to-moderate decrease in color vision is noted bilaterally. The remainder of the examination shows no abnormalities. Toxicity from which of the following is the most likely cause of this patient’s blurred vision?

A 45-year-old man with alcoholic cirrhosis comes to the physician for a routine examination. His medications are spironolactone and furosemide. He no longer drinks alcohol. He is alert and fully oriented. His temperature is 37°C (98.6°F), pulse is 86/min, respirations are 12/min, and blood pressure is 108/60 mm Hg. Examination shows scattered spider angiomas over the chest and upper abdomen. The abdomen is distended; there is dullness to percussion over the flanks. Which of the following is the most appropriate screening test for this patient?

A 19-year-old man is brought to the emergency department 30 minutes after he was involved in a motor vehicle collision. He was the unrestrained driver. A cervical collar and spinal board were placed at the scene. He has no history of serious illness and takes no medications. On arrival, he reports shortness of breath and difficulty breathing, especially in the right side of the chest. His temperature is 36.9°C (98.5°F), pulse is 126/min, respirations are 30/min, and blood pressure is 110/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 78%. Examination shows right-sided supraclavicular fossal distention with inspiration. Which of the following is the most likely diagnosis?

A previously healthy 67-year-old woman is brought to the emergency department because of a 2-hour history of severe upper abdominal pain, nausea, and vomiting. Her symptoms began when her 4-year-old grandson jumped on her abdomen while she was lying on the sofa. She is in acute distress. Her temperature is 37.7°C (99.9°F), pulse is 110/min, respirations are 20/min, and blood pressure is 150/60 mm Hg. Decreased breath sounds are heard in the lung bases bilaterally. Cardiac examination shows no other abnormalities. Abdominal examination shows diffuse tenderness to palpation; bowel sounds are decreased. Laboratory studies show:

Hemoglobin: 11 g/dL

Leukocyte count: 8500/mm³

Serum:

Ca²⁺: 7.5 mg/dL

Creatinine: 1.9 mg/dL

Total bilirubin: 0.9 mg/dL

AST: 30 U/L

ALT: 29 U/L

Amylase: 348 U/L

Lipase: 189 U/L (N = 14–280)

Which of the following is the most likely diagnosis?

Researchers would like to review the evidence on the association between cigarette smoking and cardiovascular disease. They review a sample of 500 studies published during the past 50 years and note that the increased risk for cardiovascular disease in patients positively correlates with the number of cigarettes smoked daily. The researchers also note that all of these studies are observational. They conclude that this type of study design cannot determine a causal link between smoking and cardiovascular disease, but these studies support one of the criteria for causality. Which of the following best represents the causation criterion met by this type of association?

A 23-year-old woman comes to the physician to learn the results of a PPD skin test performed 48 hours ago. The test is required before she begins her first year of nursing school. She feels well. She emigrated from Thailand at the age of 15 years. She received the bCG vaccine during infancy. She has no history of serious illness and takes no medications. She has no known exposure to anyone with tuberculosis or respiratory symptoms. She does not drink alcohol. Vital signs are within normal limits. Examination shows no abnormalities. The PPD skin test shows 15 mm of induration. An x-ray of the chest shows no abnormalities. Which of the following is the most appropriate next step in management?

 A 76-year-old woman is brought to the emergency department because of a 2-day history of severe, right-sided chest pain that increases with deep inspiration and coughing. She also has a 1-week history of intermittent fever, malaise, and loss of appetite. Ten days ago, she was diagnosed with pneumonia of the right lower lobe. Azithromycin therapy was begun at that time. She has no other history of serious illness and takes no other medications. On arrival, her temperature is 39.5°C (103.1°F), pulse is 92/min, and blood pressure is 120/75 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 94%. On pulmonary examination, there is egophony and dullness to percussion over the right lower lobe. Breath sounds are decreased on the right. A chest x-ray shows a right pleural effusion. Thoracentesis is performed; pleural fluid analysis shows a leukocyte count of 16,000/mm3, glucose concentration of 50 mg/dl_, and pH of 7.12. Which of the following is the most appropriate next step in management?

A 45-year-old woman with type 2 diabetes mellitus comes to the physician because of a 6-month history of mild pain and swelling of her right hand; the pain radiates to her shoulder. During this time, she also has had episodes of numbness and tingling of her right thumb and index and ring fingers, especially after prolonged typing. She has not sustained any recent injury. She is right-hand dominant. Her medications are insulin and ibuprofen. Vital signs are within normal limits. The neck is nontender, and range of motion is full. Spurling test is negative. Muscle strength is 5/5 in the supraspinatus, infraspinatus, and subscapularis. Radial pulses are 2+ bilaterally. Motor and sensory testing of the radial, median, and ulnar nerves shows no abnormalities. There is no thenar atrophy. Phalen test is positive on the right and negative on the left. Impingement testing is negative. Which of the following is the most appropriate next step in management?

A 70-year-old woman is admitted to the hospital because of a 1 -hour history of severe right-sided chest pain, shortness of breath, and dizziness. During this time, she also has had several coughing episodes, one of which produced blood-tinged sputum. Eighteen hours ago, she returned home from a cross-country airplane trip to see her daughter and grandchildren. The patient has no history of serious illness and takes no medications. She does not smoke cigarettes or drink alcohol. She follows a vegetarian diet, is physically fit, and exercises daily. She appears anxious. She is 163 cm (5 ft 4 in) tall and weighs 45 kg (100 lb); BMI is 17 kg/m2. Her pulse is 98/min, respirations are 16/min, and blood pressure is 106/84 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 88%. Examination shows jugular venous distention. Breath sounds are normal. On cardiac examination, S2 is increased; no murmurs are heard. Examination of the left calf shows tenderness to palpation and a positive Homans sign. Which of the following is the strongest predisposing risk factor for this patient’s in-hospital mortality?

A 3-year-old boy is brought to the physician for a well-child examination. He is at the 50th percentile for height, weight, and head circumference. His appetite is good. His pulse is 85/min. His blood pressure is 140/75 mm Hg and 140/78 mm Hg in the right and left upper extremities, respectively. His blood pressure is 144/76 mm Hg and 145/79 mm Hg in the right and left lower extremities, respectively. Funduscopic, cardiopulmonary, and abdominal examinations show no other abnormalities. Results of a complete blood count; serum electrolyte, urea nitrogen, and creatinine concentrations; and urinalysis are within the reference ranges. Which of the following is the most appropriate next step in diagnosis?