CK- NBME 10 – Block 3

A 67-year-old man comes to the physician because of a 2-month history of progressive shortness of breath on exertion, muscle pain, fatigue, generalized weakness, and constipation. He also has had a decreased appetite, resulting in a 7-kg (15-lb) weight loss during this period. His current medications are hydrochlorothiazide for hypertension and laxatives. He smoked one pack of cigarettes daily for 40 years but quit 5 years ago. His temperature is 37.5°C (99.5°F), pulse is 85/min, respirations are 22/min, and blood pressure is 164/92 mm Hg. There is no jugular venous distention. Breath sounds are decreased, and scattered rhonchi are heard over the right upper lung field. Cardiac examination shows no abnormalities. Laboratory studies show:

Hemoglobin: 14.2 g/dL

Leukocyte count: 11,500/mm³ (with a normal differential)

Serum:

Na⁺: 140 mEq/L

K⁺: 3.5 mEq/L

Cl⁻: 100 mEq/L

HCO₃⁻: 25 mEq/L

Ca²⁺: 13.3 mg/dL

Urea nitrogen: 22 mg/dL

Glucose: 72 mg/dL

Creatinine: 0.8 mg/dL

Alkaline phosphatase: 100 U/L

A chest x-ray shows a mass in the upper lobe of the right lung that extends into the hilum. Which of the following is the most likely cause of these laboratory findings?

A 23-year-old woman comes to the physician for a follow-up examination. Six months ago, she underwent splenectomy because of injuries sustained in a motor vehicle collision. Her postoperative course has been uncomplicated. She has a headache once monthly and takes acetaminophen as needed. Immunizations are up-to-date. Vital signs are within normal limits. Examination shows no abnormalities except for a well-healed scar. She asks if any precautions are required before her dental appointment in 1 week. Which of the following is the most appropriate recommendation?

Two days before undergoing removal of four molar teeth, a 27-year-old man comes to the physician for therapy to prevent excessive bleeding. He has a lifelong history of mild mucosal bleeding. His sister has a history of similar bleeding. Examination shows no abnormalities. Laboratory studies show:

Platelet count: 225,000/mm³

Bleeding time: 11 min

Prothrombin time (PT): 11 sec (INR = 1)

Partial thromboplastin time (PTT): 47 sec

Factor VIII: 15% of normal (reference range: 50%–150% of normal)

Which of the following is the most likely explanation for these findings?

An 87-year-old woman with metastatic ovarian cancer has poorly controlled pain. Her cancer has been unresponsive to chemotherapy. Current medications include long-acting oral morphine, short-acting morphine as needed, and docusate. Her family is having difficulty caring for her at home. The patient’s oldest daughter calls the physician to discuss her mother’s care. She says, “We want my mother to receive hospice care at home, but no one wants her to die at home. Can she still have hospice services?” Which of the following is the most appropriate response?

A 3-year-old girl is admitted to the hospital because of a 7-day history of fever and irritability. Treatment with acetaminophen has not resolved her symptoms. During the past 2 days, she has had a decreased appetite but a normal fluid intake. She appears irritable. Her temperature is 38.7°C (101.7°F). Examination shows nontender, bilateral, cervical lymphadenopathy. The sclerae are injected without exudates. There is an erythematous papular rash over the perineum. Examination of the hands and feet shows erythema and tenderness. Her hemoglobin concentration is 10.2 g/dL, and platelet count is 285,000/mm3. Urinalysis shows 50 WBC/hpf and no bacteria. Which of the following is the most appropriate pharmacotherapy?

A 33-year-old woman, gravida 2, para 1, at 35 weeks’ gestation is admitted to the hospital because of a 1-hour history of moderate, bright red vaginal bleeding. During this time, she has saturated two sanitary pads. She has not felt contractions or loss of amniotic fluid and reports good fetal movement. She has received no prenatal care. Her first pregnancy ended in cesarean delivery at term because of fetal bradycardia. She is unemployed and lives in a local homeless shelter. She has a history of cocaine use but has not used cocaine during the past 2 months. Her temperature is 37°C (98.6°F), pulse is 100/min and regular, and blood pressure is 90/60 mm Hg. The abdomen is nontender and consistent in size with a 35-week gestation. External fetal monitoring shows a heart rate of 150/min with moderate variability, several spontaneous accelerations, and occasional variable decelerations. An external tocometer shows irregular uterine contractions. Examination shows a small amount of bright red blood at the perineum. Which of the following is the most appropriate next step in management?

A 27-year-old man is brought to the emergency department 50 minutes after he sustained a gunshot wound to his right leg. He was injured while attempting to flee a crime scene. Paramedics report significant bright red bleeding that was controlled with pressure dressings at the scene. On arrival, the patient is conscious and responsive. His pulse is 100/min and regular, respirations are 18/min, and blood pressure is 100/85 mm Hg. Examination shows a single gunshot entry and exit wound in the right thigh with moderate oozing of bright red and dark blood but no pulsatile bleeding. The mid thigh is edematous. The right femoral pulse is palpable; no popliteal or pedal pulses are palpable. The right ankle brachial index is 0.5 (ISM) at the dorsalis pedis. The remainder of the examination shows no abnormalities. In addition to intravenous fluid administration, which of the following is the most appropriate next step in management?

A 67-year-old man comes to the physician 1 hour after a 5-minute episode of moderate left-sided chest pain that began while he was unloading groceries. The pain radiated to the left jaw. During the past 3 months, he also has had progressive shortness of breath when lying down. He has a 1-year history of decreasing stamina; he now often has to stop and rest while taking out the trash. He has well-controlled hypertension, well-controlled type 2 diabetes mellitus, and chronic bronchitis. His medications are hydrochlorothiazide, metoprolol, glipizide, and a nebulized albuterol inhaler as needed. He smoked one and one-half packs of cigarettes daily for 40 years but quit 10 years ago. His temperature is 37.2°C (99°F), pulse is 100/min, respirations are 16/min, and blood pressure is 100/58 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 90%. Examination shows jugular venous distention. Crackles are heard at both lung bases. On cardiac examination, there is an S3 and a grade 2/6 harsh, late-peaking, systolic murmur heard best at the upper right sternal border. There is 2+ pitting edema of the lower legs. Which of the following is the most appropriate next step in diagnosis?

A 57-year-old man comes to the physician because of a 10-year history of an intermittent rash on his face. The rash worsens with cold weather and stress. Examination shows a scaly, erythematous rash in several areas around the nose and eyebrows. There is dandruff from the scalp. Which of the following is the most likely diagnosis?

A 77-year-old man with hypertension comes to the physician for a routine examination. His medications are metoprolol and simvastatin. His father died of a cerebral infarction. The patient smoked one pack of cigarettes daily for 25 years but quit 10 years ago. He walks 2 miles daily. He is 180 cm (5 ft 11 in) tall and weighs 82 kg (180 lb); BMI is 25 kg/m2. His pulse is 70/min, and blood pressure is 140/90 mm Hg. Examination shows no abnormalities. Serum studies show a cholesterol concentration of 210 mg/dL. Results of a recent cardiac stress test are negative. Which of the following is the strongest predisposing factor for cerebral infarction in this patient during the next 5 years?

A 32-year-old woman comes to the physician because of weakness in her right leg that began 1 week ago and has resolved over the past 24 hours. She is currently asymptomatic. Two years ago, she had tingling in both hands and an “electric-like” sensation down her spine when she flexed her neck; her symptoms resolved after 3 weeks. Six months ago, she had visual loss in her right eye and pain with eye movement. Examination at that time showed a right central scotoma that resolved after 2 weeks. She has a history of mitral valve prolapse. She takes no medications. Her pulse is 64/min and regular, and blood pressure is 100/60 mm Hg. Cardiac examination shows a systolic click. Funduscopic examination shows mild pallor of the right optic disc; there is no afferent pupillary defect. Muscle strength is normal. Deep tendon reflexes are 2 in the upper extremities and 3 in the lower extremities. Babinski sign is present on the right. An MRI of the brain is shown. Which of the following is the most appropriate treatment for this patient?

A 27-year-old man is brought to the emergency department by police 1 hour after they found him lying in the street and proclaiming himself to be invulnerable to death because he is “the Antichrist.” He is not able to give a coherent history, but imipramine and thioridazine bottles are found in his pocket. He appears somnolent. His pulse is 88/min, respirations are 20/min, and blood pressure is 110/70 mm Hg. Physical examination shows red, dry skin and dilated pupils. Serum electrolyte concentrations are within the reference ranges. An ECG shows a prolonged QT interval. The patient is admitted to the intensive care unit. Which of the following is the most appropriate next step in diagnosis?

A 62-year-old man comes to the physician because of sadness and difficulty sleeping since his wife of 35 years died of breast cancer 7 months ago. He began grieving for her before she died, but the grief has become more intense since her death. During this period, he has had loss of appetite and is no longer interested in golfing and having dinner with friends. He has started to believe that he will never feel better and sees himself as worthless. Physical examination shows no abnormalities. Mental status examination shows a depressed mood and sad affect. He says that life is no longer tolerable, but he has not thought about killing himself. Which of the following is the most likely diagnosis?

A 20-year-old man is brought to the physician by his parents because of auditory hallucinations and bizarre behavior over the past year. He recently dropped out of college and moved back home with his parents. He has not attempted to find a job. He says that he has been feeling strange, “like being in a dream,” and talks to his great-great-grandfather who died 50 years ago. He was diagnosed with hepatitis A 2 years ago after an episode of jaundice, and he has been treated with thyroxine for hypothyroidism for the past 6 months. His pulse is 68/min, respirations are 10/min, and blood pressure is 100/70 mm Hg. Physical examination shows hyperreflexia of the lower extremities and mild resting tremor of the upper extremities. On mental status examination, his voice is monotonous, his face is immobile, and he seems very anxious. He stares at the physician and barely answers questions. Serum studies show:

Total bilirubin: 1 mg/dL

Thyroid-stimulating hormone (TSH): 1 µU/mL

AST: 21 U/L

ALT: 20 U/L

Urine toxicology screening is negative. Which of the following is the most likely diagnosis?

A 37-year-old man comes to the physician because of a 1-week history of pain with swallowing. He received the diagnosis of AIDS 4 years ago, but he has not been able to tolerate highly active antiretroviral therapy. He currently takes trimethoprim-sulfamethoxazole. Vital signs are within normal limits. Examination shows a few white plaques over the pharynx. No other abnormalities are noted. Laboratory studies show a CD4 T-lymphocyte count of 50/mm3 (Normal>500) and a plasma HIV viral load of 50,000 copies/mL. Which of the following is the most appropriate pharmacotherapy?

A randomized placebo-controlled trial is initiated to investigate the use of a new medication for the treatment of hypertension. The trial enrolled 1000 men and women ages 40 years and older; these patients are equally randomized to either the new medication or a placebo. The primary outcome was established as cardiovascular death or morbidity. After 1 year, 4.2% of patients taking the new medication experienced the primary outcome as determined by hospital records, compared with 3.4% of patients taking placebo (P=.52). The investigators then reanalyze the outcomes for only African American study patients. Of the 250 African American patients in the study, 2.4% of those taking the new medication experienced the primary outcome, compared with 6.0% in the placebo group (P=.03). The investigators conclude that the medication is effective only for African American patients. Which of the following is the primary threat to the validity of this conclusion?

A2608-g (5-lb 12-oz) newborn is delivered at term to a 32-year-old primigravid woman who received no  prenatal care. Examination of the newborn shows generalized hypertonia. Meconium testing for cocaine metabolites is positive. A review of the literature shows that this screening test has a sensitivity of 100% and a true-negative rate of 90%. Which of the following is necessary to calculate the positive predictive value of the test?

A study is being conducted to investigate the association between childhood exposure to secondhand cigarette smoke and risk for developing lung disease as an adult in individuals who have never smoked. A total of 500 adults with lung disease and 500 adults with no history of lung disease are enrolled in the study; participants in both groups are interviewed about exposure to secondhand cigarette smoke during childhood. Which of the following is the most appropriate measure of association for the investigators to report?

A study is conducted to assess the incidence of mortality in children with idiopathic seizure disorder and children without seizure disorder. A total of 1283 age-matched patients without significant comorbidities are enrolled in the study and observed for 20 years. Results show that the mortality rate among the 692 children with seizure disorder for the 20-year period following diagnosis is 6.2%, whereas the mortality rate among the 591 children without seizure disorder for the same 20-year period is 0.8%. Which of the following is the most accurate conclusion based on this study population?

A 67-year-old woman is brought to the emergency department by her daughter because of a 2-day history of progressive fatigue, confusion, shortness of breath with exertion, and difficulty breathing when she lies flat. At night, she has had the sudden need to run to an open window for air. She had a myocardial infarction 2 years ago but has had no recent chest pain. Her medications are metoprolol, lisinopril, spironolactone, and furosemide. The daughter says that she does not know if her mother has taken her medications during the past 2 days. On arrival, the patient appears ill and in mild respiratory distress; she is ashen. Her temperature is 36.4°C (97.6°F), pulse is 102/min and regular, respirations are 24/min, and blood pressure is 82/46 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 89%. Examination shows jugular venous distention. Crackles are heard throughout the lower lung fields. On cardiac examination, an S3 gallop is heard. There is 2+ pitting edema at the ankles. Intravenous administration of which of the following is the most appropriate next step in pharmacotherapy?