CK- NBME 10 – Block 2

A previously healthy 42-year-old woman, gravida 3, para 3, comes to the physician because of a 3-month history of progressive urinary incontinence. She has loss of urine with coughing, sneezing, and exercising. Her last bowel movement was 3 days ago. She has no history of gynecologic illness. She has gastroesophageal reflux disease treated with omeprazole and hypertension treated with hydrochlorothiazide. Her children were born following uncomplicated vaginal deliveries. Her blood pressure is 120/70 mm Hg. Physical examination shows no abnormalities. Pelvic examination shows bulging of the anterior vaginal wall. Her postvoid residual volume is 50 ml_. Urinalysis shows no blood, WBCs, or nitrites. There is loss of urine on cough stress test. Which of the following is the most likely cause of this patient’s loss of urine?

A 42-year-old man is admitted to the hospital because of a 2-day history of fever, chills, cough, and shortness of breath. He currently takes atenolol for hypertension and pravastatin for hyperlipidemia. He has smoked one pack of cigarettes daily for 20 years. He underwent splenectomy at the age of 18 years for injuries sustained in a motorcycle collision. He appears pale and is in moderate distress. His temperature is 40°C (104°F), pulse is 120/min, respirations are 22/min, and blood pressure is 100/60 mm Hg. Crackles and decreased breath sounds are heard over the left lower lung field; there is dullness to percussion. Examination shows no other abnormalities. A Gram stain of sputum shows gram-positive diplococci. Treatment with ceftriaxone is begun. An x-ray of the chest shows an infiltrate and pleural effusion on the left. Thoracentesis is performed. Laboratory studies show: A Gram stain of the pleural fluid shows many segmented neutrophils and gram-positive diplococci.

Pleural fluid:

pH: 6.8

Glucose: 30 mg/dL

Lactate dehydrogenase (LDH): 850 U/L

Arterial blood gas analysis on room air:

pH: 7.44

PCO₂: 32 mm Hg

PO₂: 68 mm Hg

Which of the following is the most appropriate next step in management of the pleural effusion?

A 17-year-old boy with intellectual developmental disorder is brought to the physician because of low-grade fever and abdominal pain for 6 days. His temperature is 37.8°C (100.1°F), pulse is 110/min, respirations are 22/min, and blood pressure is 120/70 mm Hg. Examination shows splinter hemorrhages under the nails. A grade 2/6 systolic murmur is heard best at the upper left sternal border. There is a systolic ejection click. S1 and S2are normal. Abdominal examination shows splenomegaly. Laboratory studies show:

Hemoglobin: 9.1 g/dL

Leukocyte count: 30,000/mm³

Platelet count: 928,000/mm³

Erythrocyte sedimentation rate (ESR): 110 mm/h

Urine:

Blood: 2+

Protein: 1+

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

A 77-year-old man is brought to the physician by his wife because of a 1-year history of poor balance, weakness of his legs, and numbness of his toes and feet. His wife states that he is not as mentally sharp as he was 1 year ago. He has peptic ulcer disease and hypertension. Current medications are hydrochlorothiazide and ranitidine. His blood pressure is 148/88 mm Hg. Examination shows normal muscle tone and strength in the upper and lower extremities. Deep tendon reflexes are 2+ in the upper extremities, 3+ at the knees, and absent at the ankles. Babinski sign is present. Proprioception and sensation to vibration are markedly decreased at the ankles and toes. He has a broad- based but steady gait. On mental status examination, he is oriented to month, day, and year. He can name the current president but none of the previous presidents. Mean corpuscular volume is 105 pm3, and serum lactate dehydrogenase activity is 210 U/L. A serologic test for syphilis is negative. MRI of the brain shows mild cortical atrophy, enlarged ventricles, and multiple small areas of T2 hyperintensities in the white matter. Which of the following is the most likely diagnosis?

A 42-year-old woman, gravida 5, para 4, at 14 weeks’ gestation comes to the physician for a routine prenatal visit. Prior to conception, menses had occurred at regular 28-day intervals. Her temperature is 37°C (98.6°F), pulse is 80/min, respirations are 20/min, and blood pressure is 120/80 mm Hg. Examination shows a closed cervix and a uterus consistent in size with a 6-week gestation. Ultrasonography shows a normal uterus with a gestational sac and no cardiac activity. Which of the following is the most likely diagnosis?

A 4-year-old girl is brought to the physician because of a 3-month history of episodic abdominal pain and loose stools that recur several times weekly. She has not had nausea, vomiting, or decreased appetite. Her development has been appropriate for age. She received the diagnosis of type 1 diabetes mellitus 9 months ago, and her most recent hemoglobin A1c was 7.5%. Her only medication is insulin. She appears well. She is at the 25th percentile for height and 10th percentile for weight, as she was at her last examination 4 months ago. Her temperature is 36.7°C (98°F), pulse is 100/min, respirations are 24/min, and blood pressure is 95/60 mm Hg. The conjunctivae are pale. A grade 1/6, systolic ejection murmur is heard at the left sternal border. The abdomen is mildly distended but soft and nontender; there is no hepatosplenomegaly. The remainder of the examination shows no abnormalities. Laboratory studies show:

Hemoglobin: 10 g/dL

Mean corpuscular volume (MCV): 67 µm³ (Normal = 70–74)

Leukocyte count: 8,500/mm³

Platelet count: 250,000/mm³

Red cell distribution width (RDW): 18% (Normal = 13%–15%)

Additional serum studies are most likely to show an increase in which of the following?

A 24-year-old man comes to the clinic because of a 2-day history of severe mouth pain, fever, sore throat, and malaise. He has no known sick contacts. He has no history of serious illness and takes no medications. He recently returned home from active duty deployment in the US Air Force. His temperature is 38.7°C (101.7°F). Examination shows cervical lymphadenopathy. There are multiple small vesicles over the inside of the mouth and posterior oropharynx. Soft tissue fullness is noted. Which of the following is the most appropriate next step in diagnosis?

A 23-year-old man with schizophrenia is brought to the emergency department by his mother 28 hours after the onset of progressive confusion and agitation. He has had increased thirst during this period. One week ago, he was discharged after treatment for the second exacerbation of schizophrenia. Current medications include haloperidol and benztropine. He appears flushed. His temperature is 38°C (100.4°F), pulse is 100/min, and blood pressure is 160/90 mm Hg. Examination shows dry mucous membranes. Pupils are 4 mm and reactive to light. On mental status examination, he is not oriented to person, place, or time. Which of the following is the most likely explanation for these findings?

A previously healthy 18-year-old primigravid African American woman at 18 weeks’ gestation is brought to the emergency department because of a 2-day history of fever and a 12-hour history of severe left-sided back pain. She has had no prenatal care. Her family history is unknown because she was adopted. Her temperature is 39.1°C (102.4°F), pulse is 110/min, and blood pressure is 100/62 mm Hg. Examination shows left costovertebral angle tenderness. The uterus is consistent in size with an 18-week gestation. Laboratory studies show:

Hemoglobin: 7.9 g/dL

Hemoglobin electrophoresis:

Hemoglobin A₁: 14%

Hemoglobin A₂: 4%

Hemoglobin F: 7%

Hemoglobin S: 75%

Mean corpuscular volume (MCV): 90 µm³

Platelet count: 159,000/mm³

Urine:

Bacteria: 3+

WBCs: 3+

In addition to antibiotic treatment, which of the following is the most appropriate pharmacotherapy?

A 67-year-old man comes to the physician because of easy fatigability and generalized weakness for 3 months and left chest pain for 1 month. The chest pain is worse on deep inspiration. He appears slightly pale. There is tenderness over the left 8th and 9th ribs laterally. Examination shows no other abnormalities. His hematocrit is 28%. Serum and urine protein electrophoresis shows a monoclonal spike. A biopsy specimen of bone marrow shows greater than 50% plasma cells. An x-ray of the chest shows 1 – to 1,5-cm areas of radiolucency in both ribs corresponding to the sites of tenderness. This patient’s condition makes him most susceptible to infection with which of the following organisms?

A study is conducted to assess the efficacy of a new drug for the treatment of hypertension. A total of 6000 patients are enrolled in the study; 50% of the patients receive the new drug and 50% receive standard antihypertensive therapy. The goal is to confirm efficacy and assess for adverse effects. The study builds on other studies done previously to assess safe dosing range, drug administration protocol, and initial efficacy. Which of the following best describes the phase of this clinical trial?

State health officials are planning to implement a new skin cancer screening program in agricultural workers in several southern states who are occupationally exposed to the sun. The screening program will consist of annual visual skin examinations. Some researchers are concerned about the limited effectiveness of the program. Which of the following is most likely to cause overestimation of the effectiveness of this screening program?

 A study is conducted to assess the efficacy of a new drug for treatment of pruritus secondary to primary sclerosing cholangitis (PSC). A total of 300 patients with PSC are enrolled and randomly assigned to one of two groups: 150 patients receive the new drug (Drug X), and 150 patients receive the placebo. Pruritus is evaluated at the start of the study and after 1 week of treatment. The results show:

Based on these data, which of the following represents the number needed to treat for 1 week with Drug X to prevent one case of PSC pruritus in this population?

A prospective cohort study is conducted to assess the likelihood of undergoing repeat cesarean delivery after a trial of labor with or without oxytocin. Oxytocin use and mode of delivery are recorded from hospital records for all deliveries in one calendar year. The results show:

Based on these results, which of the following represents the relative risk for a repeat cesarean delivery with oxytocin use?

A 9-year-old boy is brought to the office by his parents because of bilateral groin hernias discovered by a nurse on examination 5 days ago at an urgent care clinic. The patient’s parents are migrant agricultural workers, and the patient’s medical care has been inconsistent and infrequent. The parents say their son has no history of serious illness; he has only occasional upper respiratory tract infections that resolve after treatment with over-the-counter medications. The patient currently receives no medications. The nurse reports that she administered several routine vaccines to the patient because he had not received them yet. He is at the 80th percentile for height and 20th percentile for weight. Examination shows an elongated face, droopy eyelids, and mild scoliosis. There is mild pectus carinatum. Cardiopulmonary and abdominal examinations show no abnormalities. The distance encompassed by the patient’s outstretched upper extremities is 1.2 times his height. On Valsalva maneuver, bilateral hernias below the inguinal ligaments are easily reducible. In addition to scheduling operative repair of the hernias, which of the following is the most appropriate next step in management?

A 3-year-old girl is brought to the emergency department after her mother found her in the kitchen next to an open bottle of drain cleaner that had been stored under the sink. The bottle was still almost full, but some of its contents were spilled on the patient’s clothes and on the floor. On arrival, she is alert, crying, and drooling but in no respiratory distress. Her pulse is 120/min, respirations are 30/min, and blood pressure is 95/70 mm Hg. The mouth and oral mucosa is bright red, but there are no ulcers in the oropharynx. The lungs are clear to auscultation. Abdominal examination shows no abnormalities. The extremities are well perfused. An x-ray of the chest shows clear lung fields and normal cardiac silhouette and mediastinum. Which of the following is the most appropriate next step in management?

A 42-year-old woman is brought to the emergency department 30 minutes after her husband found her unconscious in her bed. She has a 6-year history of systemic lupus erythematosus treated with prednisone. Her husband says she has been on a drinking binge for the past 7 days and has not been eating. Three days ago, she had the onset of rhinitis, conjunctivitis, and a nonproductive cough. She has a long-standing history of alcoholism. She moans in response to painful stimuli. Her temperature is 38.9°C (102°F), pulse is 110/min, respirations are 22/min, and palpable systolic blood pressure is 80 mm Hg. The lungs are clear to auscultation and percussion. Abdominal examination shows no abnormalities. Fluid resuscitation is begun. Which of the following is the most appropriate initial step in management?

A 32-year-old woman comes to the physician because of a 2-week history of double vision and dry, red eyes. She also has had a 4.5-kg (10-lb) weight loss and increased fatigability during this time. Her only medication is an oral contraceptive. She is 163 cm (5 ft 4 in) tall and weighs 50 kg (110 lb); BMI is 19 kg/m2. Her temperature is 37.2°C (99°F), pulse is 100/min, respirations are 16/min, and blood pressure is 135/60 mm Hg. Examination shows prominent-appearing eyes and bilateral scleral injection. She has limited upward gaze, and she reports severe diplopia when she looks up; the eyes open wider on downward gaze. Visual acuity is 20/40 in the left eye and 20/30 in the right. Which of the following is the most appropriate next step in diagnosis?

A 16-year-old boy with type 1 diabetes mellitus is brought to the emergency department by his parents because of a 1-hour history of vomiting. The parents say he was at an overnight camp during the past week. When he returned 12 hours ago, he was not as active as usual and said he was tired. The patient told his parents that he had taken his insulin while at camp, but when they checked his bag, his supply of insulin indicated that he had not been taking it regularly. On arrival, he appears ill and drowsy but fully oriented. There is a sweet odor to his breath. His temperature is 37°C (98.6°F), pulse is 120/min, respirations are 26/min and deep, and blood pressure is 115/60 mm Hg. Examination shows dry mucous membranes. No other abnormalities are noted. Laboratory studies show:

Fingerstick blood glucose: >600 mg/dL

Serum HCO₃⁻: 10 mEq/L

Arterial blood gas analysis on room air shows:

pH: 7.13

PCO₂: 32 mm Hg

PO₂: 95 mm Hg

Administration of which of the following is the most appropriate intial step in management?

A 17-year-old boy is brought to the physician for an examination prior to participation in sports. He has no history of serious illness and takes no medications. He was diagnosed with intellectual developmental disorder at the age of 5 years. He is 165 cm (5 ft 5 in) tall and weighs 50 kg (110 lb); BMI is 18 kg/m2. Vital signs are within normal limits. Examination shows minimal facial hair. There is mild bilateral gynecomastia. The testes are Tanner stage 1. Which of the following is the most likely explanation for this patient’s gynecomastia?