NBME 13 – Block 4

A 57-year-old woman with metastatic cancer of the sigmoid colon is admitted to the hospital because of a 2-day history of progressive swelling and pain of her right arm. Ten days ago, she underwent partial resection of the liver and placement of a right subclavian venous port. She currently takes no medications. Examination today shows a swollen, tender right forearm and hand. Venous duplex ultrasonography shows thrombosis of the right axillary and subclavian veins. The port and catheter are removed, and intravenous unfractionated heparin therapy (UHT) is begun. After 2 days of UHT, the patient’s pain has decreased. Laboratory studies on admission and after 2 days of UHT show:

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

A 37-year-old woman, gravida 1, para 1, comes to the physician for a postpartum examination 6 weeks after spontaneous vaginal delivery of a 3220-g (7-lb 1-oz) newborn. Delivery was complicated by a vaginal laceration, which was repaired. She states that she has had occasional fecal incontinence and flatus since delivery; she has not had urinary incontinence, fever, diarrhea, constipation, or pelvic pain. She has Crohn disease treated with prednisone; her last flare-up of symptoms was 6 months before delivery. Her temperature is 37°C (98.6°F). Physical examination shows that the sutures in the vaginal mucosa are healing well. There is a 3-cm defect in the rectal mucosa with communication with the vagina. The anal sphincter is partially torn. Without treatment, which of the following is the most likely outcome for this patient?

A 42-year-old man comes to the physician 12 hours after the onset of increasing mild epigastric pain and decreased appetite. He has not eaten during this period. He has vomited greenish material 10 times during the past 4 hours. He has not had fever or chills. He was treated for malaria 25 years ago. He currently takes no medications. He immigrated to the USA from Ghana 20 years ago. He does not smoke or drink alcohol. He appears ill and is in mild distress. His temperature is 37.8°C (100.1°F), pulse is 110/min, respirations are 20/min, and blood pressure is 108/70 mm Hg. Examination shows dry mucous membranes. Cardiopulmonary examination shows no abnormalities. The abdomen is soft with mild epigastric tenderness. There is no hepatosplenomegaly. Bowel sounds are high pitched. A 3-cm tender mass is palpated in the right groin. Test of the stool for occult blood is negative. Laboratory studies show:

Abdominal x-rays are shown. In addition to placement of a nasogastric tube, which of the following is the most appropriate next step in management?

A 12-year-old boy is brought to the emergency department 15 minutes after his parents found him restless and confused in their basement. He also had slurred speech. He has no history of serious illness and takes no medications. While waiting to be examined, he falls asleep but is easily arousable. Physical examination shows nystagmus. Muscle strength is 4/5 throughout. On mental status examination, he is oriented to person and place but not to time. He reports no hallucinations. There is no evidence of delusions. Urine toxicology screening is negative. Use of which of the following substances is the most likely cause of this patient’s condition?

A 27-year-old man comes to the physician because of a painful lesion on his left palm that has been enlarging during the past 9 months. Two years ago, he underwent cauterization with liquid nitrogen for a wart-like lesion at the same site; the lesion decreased in size but never completely resolved. Since the procedure, he has had episodes of skin breakdown with clear, malodorous drainage. He is unable to grip objects with his left hand because of the pain. His temperature is 37°C (98.6°F). Examination of the left hand shows a 4 × 3-cm, erythematous, irregularly shaped lesion overlying the hypothenar eminence that rises 1 cm above the skin surface and is fixed to underlying tissue. The center of the lesion is necrotic with a serosanguineous, malodorous discharge. Sensation to pinprick is decreased over the palmar surface of the left small fingertip. The remainder of the examination shows no abnormalities. X-rays of the left hand show no abnormalities. An MRI of the hand shows a large, irregularly shaped mass extending from the skin of the hypothenar eminence into the Guyon canal and the carpal tunnel. Results of an open biopsy of the lesion show high-grade epithelioid sarcoma. A staging CT scan shows no evidence of metastases. Which of the following is the most appropriate next step in management?

An 18-year-old man is brought to the emergency department by his friends 45 minutes after sustaining injuries on his dirt bike. He reports that when landing the bike after a jump, he lost his seating and suddenly straddled the center bar of the bike, which resulted in severe pain between his legs. For 15 minutes after being injured, he was unable to ambulate. He has had similar accidents twice in the past, but the resulting pain was not as prolonged or severe. The patient is in distress. His pulse is 128/min, respirations are 14/min, and blood pressure is 152/80 mm Hg. Examination shows lacerations and ecchymoses over the face and hands. Visual examination of the scrotum shows diffuse edema and ecchymoses; the scrotum cannot be palpated because of pain. Which of the following is most likely to confirm the diagnosis?

A 12-month-old boy is brought to the physician by his mother for a well-child examination. His mother is concerned because she does not think he is gaining an adequate amount of weight. His diet consists of cow milk-based formula and solid foods. He has four bulky, light-colored stools and six wet diapers daily. He is at the 10th percentile for height, 5th percentile for weight, and 75th percentile for head circumference. He has had a 90-g (3-oz) weight gain since his most recent visit 3 months ago. Development is appropriate for age. Examination shows a paucity of subcutaneous fat and thin hair. Which of the following is the most appropriate next step in management?

A 42-year-old woman comes to the physician because she had a 2-hour episode of shortness of breath yesterday after walking for two blocks. She has not had chest pain and has no previous history of shortness of breath with exertion or at night. She has a 6-year history of poorly controlled hypertension. Her current medications are a diuretic, β-adrenergic blocking agent, and calcium-channel blocking agent. There is no family history of coronary artery disease. The patient does not smoke cigarettes. Her pulse is 85/min and irregularly irregular, respirations are 16/min, and blood pressure is 170/90 mm Hg. The lungs are clear to auscultation. On cardiac examination, S1 and S2 are normal. No murmurs are heard. Serum studies show a total cholesterol concentration of 130 mg/dL and LDL-cholesterol concentration of 90 mg/dL. An ECG shows atrial fibrillation and left ventricular hypertrophy. Which of the following is the most appropriate next step in diagnosis?

An 82-year-old woman is admitted to the hospital because of a 4-day history of dyspnea, cough productive of brown sputum, nausea, fever, and chills. She has hypertension, type 2 diabetes mellitus, and hypercholesterolemia. Her medications are amlodipine, benazepril, and atorvastatin. She has no known sick contacts. One week ago, she returned from a 15-day vacation where she stayed in a hotel for 5 days and was on a 10-day Caribbean cruise. She does not smoke cigarettes, drink alcohol, or use illicit drugs. She lives alone and is able to perform activities of daily living without difficulty. She is 163 cm (5 ft 4 in) tall and weighs 70 kg (155 lb); BMI is 27 kg/m2. Her temperature is 38.1°C (100.6°F), pulse is 116/min, respirations are 24/min, and blood pressure is 120/65 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 89%. Pulmonary examination shows dullness to percussion over the lower lobe of the left lung. Laboratory studies show a leukocyte count of 15,000/mm3, serum urea nitrogen concentration of 19 mg/dL, and serum creatinine concentration of 0.9 mg/dL. Her hemoglobin concentration, serum electrolyte concentrations, and results of urinalysis are within the reference ranges. A chest x-ray and Gram stain of sputum are shown. Which of the following is the most likely infectious agent?

A previously healthy 15-year-old girl is brought to the physician because of vaginal discharge and abdominal pain for 3 days. She has not had fever or dysuria. Menarche was at 12 years of age, and her last menstrual period was 1 week ago. She is sexually active and uses an oral contraceptive. Her temperature is 38°C (100.4°F), pulse is 80/min, respirations are 16/min, and blood pressure is 100/60 mm Hg. Abdominal examination shows normal bowel sounds with mild right lower quadrant tenderness without rebound, masses, or hepatosplenomegaly. Pelvic examination shows a friable cervix with a moderate amount of yellow discharge and scant blood. There is mild cervical motion tenderness but no adnexal tenderness or masses. Gram stain of the cervical discharge shows gram-negative intracellular diplococci. Urine β-hCG is negative. The patient does not want her parents to know that she is ill. Which of the following is the most appropriate course of action?A previously healthy 15-year-old girl is brought to the physician because of vaginal discharge and abdominal pain for 3 days. She has not had fever or dysuria. Menarche was at 12 years of age, and her last menstrual period was 1 week ago. She is sexually active and uses an oral contraceptive. Her temperature is 38°C (100.4°F), pulse is 80/min, respirations are 16/min, and blood pressure is 100/60 mm Hg. Abdominal examination shows normal bowel sounds with mild right lower quadrant tenderness without rebound, masses, or hepatosplenomegaly. Pelvic examination shows a friable cervix with a moderate amount of yellow discharge and scant blood. There is mild cervical motion tenderness but no adnexal tenderness or masses. Gram stain of the cervical discharge shows gram-negative intracellular diplococci. Urine β-hCG is negative. The patient does not want her parents to know that she is ill. Which of the following is the most appropriate course of action?

A 42-year-old woman comes to the physician for a routine health maintenance examination. She received the diagnosis of glomerulonephritis 1 year ago, which was successfully treated with corticosteroids, with resolution of her kidney failure and proteinuria. At her last visit 1 month ago, her blood pressure was 110/70 mm Hg. Her serum creatinine concentration at that time was 0.9 mg/dL, and urine dipstick was negative for protein and blood. Her only medications are lisinopril and a daily multivitamin. She swims 2 miles five times weekly. She is 165 cm (5 ft 5 in) tall and weighs 57 kg (126 lb); BMI is 21 kg/m2. Her pulse is 58/min, and blood pressure is 130/86 mm Hg. Examination, including cardiopulmonary examination, shows no other abnormalities. There is no peripheral edema. Laboratory studies show:

Which of the following is the most appropriate next step to slow progression of this patient’s renal insufficiency?

A 19-year-old man is brought to the physician by his parents because they are worried about his behavior since he dropped out of college 2 months ago. When he came home, he appeared distracted and preoccupied and would not answer their questions. He would only say that it is unsafe for him to return to school because his professors had been stealing from him and that campus police are searching for him for use in an experiment. His parents state that he has always been shy and more of a loner than their other children but that now he will not even talk to them. He has not had changes in sleep or appetite. He has no history of serious illness and takes no medications. His parents report that his maternal cousin takes medication for “psychiatric problems” and has a history of several psychiatric hospitalizations, but that they are unaware of the diagnosis. The patient is mildly malodorous and unshaven. Vital signs are within normal limits. He will not cooperate with a full physical examination but appears to move all four extremities spontaneously. On mental status examination, he is angry, mumbles to himself, and searches his pockets for something. He says he is not “depressed.” His speech is normal in rate and rhythm. Which of the following is the most likely diagnosis?

An 80-year-old man is brought to the office by his wife because of a 3-month history of “personality changes.” She says he has become withdrawn and is no longer interested in socializing with friends and family. At a restaurant last night, he sexually groped a waitress. The patient has no history of serious illness and takes no medications. Vital signs are within normal limits. Physical examination shows no abnormalities. Neurologic examination shows no focal findings. On mental status examination, he has a blunted affect and describes his mood as “fine.” He recalls two of three objects after 5 minutes. He makes no errors when performing serial sevens. Serum studies show a thyroid-stimulating hormone concentration of 3.8 mIU/L, thyroxine (T4) concentration of 5 μg/dL, and triiodothyronine (T3) concentration of 117 ng/dL; results of other laboratory studies are within the reference ranges. An MRI of the brain shows focal atrophy of the frontal and temporal lobes. Which of the following is the most appropriate next step in management?

A 58-year-old man comes to the office because of a 1-day history of progressive weakness of the left leg. He now catches his left great toe on his carpet when he walks. He has not sustained any injury or had any change in his activities. He has not had fever, chills, or bladder or bowel incontinence. He has hypertension, coronary artery disease, and type 1 diabetes mellitus. His medications are metoprolol, amlodipine, and insulin. His daily fingerstick blood glucose concentrations range between 100 mg/dL and 120 mg/dL. He is alert and fully oriented. Vital signs are within normal limits. Cranial nerves are intact. There is no tenderness to palpation of the low back; range of motion is decreased on lateral bending. Results of muscle strength testing show:

Passive range of motion of the ankles is full; no pain is elicited on ankle palpation bilaterally. Patellar and Achilles deep tendon reflexes are 2+ bilaterally. Dorsalis pedis pulses are 1+ in the lower extremities. Steppage gait is present. Which of the following is the most likely explanation for these clinical findings?

A 52-year-old woman with metastatic breast cancer comes to the physician for a follow-up examination. She has a 6-month history of bone pain in the low back and left hip that has been unresponsive to codeine (60 mg every 4 hours) and ibuprofen (800 mg every 8 hours). Six years ago, she underwent a modified radical mastectomy. One year ago, she was diagnosed with metastases to the liver and bone; she is currently receiving chemotherapy. Her pulse is 100/min, respirations are 18/min, and blood pressure is 150/90 mm Hg. Abdominal examination shows an enlarged, tender liver. There is tenderness to percussion over T3–6. Her serum alkaline phosphatase activity is 280 U/L. Which of the following is the most appropriate next step for this patient’s pain control?

A 47-year-old man comes to the physician because of a 6-month history of progressive shortness of breath on exertion and fatigue. He has type 2 diabetes mellitus, essential hypertension, obstructive sleep apnea, gastroesophageal reflux disease, and hypercholesterolemia. His medications are metformin, benazepril, famotidine, and atorvastatin. He uses a continuous positive airway pressure machine. He does not smoke cigarettes or drink alcohol. He is 168 cm (5 ft 6 in) tall and weighs 127 kg (280 lb); BMI is 45 kg/m2. His temperature is 37°C (98.6°F), pulse is 98/min, respirations are 20/min, and blood pressure is 138/86 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 86%. Examination shows mild circumoral cyanosis. Pulmonary examination shows no abnormalities. On cardiac examination, there is a split S2 and a prominent P2; no murmurs, gallops, or rubs are heard. Abdominal examination shows no hepatomegaly or ascites. There is 2+ pretibial and ankle edema bilaterally. Which of the following is most likely to be decreased in this patient?

A 27-year-old man is admitted to the hospital for treatment of injuries sustained in a motor vehicle collision. He states that he was feeling “out of it” at the time of the collision but feels better now. He is employed as a truck driver. During the past 6 months, he had three prior collisions but sustained only minor bruises and abrasions. He attributes the collisions to difficulty concentrating, especially when he drives long distances without eating. He has not had chest pain. He has no history of serious illness and takes no medications. He does not drink alcohol or use illicit drugs. He is alert and fully oriented. Examination shows no abnormalities except for tenderness over the left shoulder and muscles of the left upper extremity. His fingerstick blood glucose concentration is 39 mg/dL. Results of laboratory studies are otherwise within the reference ranges. Which of the following is the most appropriate next step in diagnosis?

A 25-year-old man comes to the office for a routine health maintenance examination. He has no history of serious illness and takes no medications. He has smoked one pack of cigarettes daily for 7 years. His blood pressure is 150/88 mm Hg. A grade 3/6, harsh, midsystolic, crescendo-decrescendo murmur is heard best at the upper left sternal border with radiation to the neck. The murmur is louder with Valsalva maneuver. The point of maximal impulse is at the anterior axillary line in the fifth intercostal space. An ECG is shown. Which of the following is the most likely cause of this patient’s murmur?

A 29-year-old primigravid Vietnamese woman at 6 weeks’ gestation comes to the office for her first prenatal visit. She has no history of serious illness, and her only medication is a prenatal vitamin. The uterus is consistent in size with a 6-week gestation. Laboratory studies show a hemoglobin concentration of 9.8 g/dL and mean corpuscular volume of 72 μm3. Her serum ferritin concentration is 42 ng/mL. Which of the following is the most appropriate next step in management?

 52-year-old woman is brought to the office by her husband for evaluation of mild aphasia and change in her personality. CT scan of the head discloses a 3-cm mass in the left temporal lobe and a 5-cm mass in the right frontal lobe. She has smoked one pack of cigarettes for 30 years. Chest x-ray is reported as showing a “2-cm spiculated mass in the left subapical region.” The radiologist calls the physician and says that the lesion was present on her prior chest x-rays done 10 months ago. Which of the following is the most appropriate next step in management?

A 24-year-old African American woman comes to the office because of a 2-week history of progressive bilateral hearing loss. She says that during the past 3 months, she also has had ringing in her ears. She has asthma, hypothyroidism, and a history of recurrent ear infections during childhood. Current medications include inhaled albuterol as necessary and levothyroxine. Her mother and one of her five siblings are deaf. The patient works as a bartender. She is 165 cm (5 ft 5 in) tall and weighs 68 kg (150 lb); BMI is 25 kg/m2. Temperature is 36.8°C (98.2°F), pulse is 88/min, respirations are 20/min, and blood pressure is 144/87 mm Hg. On physical examination, the tympanic membranes cannot be observed because of impacted cerumen. The remainder of the physical examination shows no abnormalities. Which of the following factors in this patient’s history most strongly indicates a poor prognosis?

A 52-year-old Chinese American woman returns to the office because of a 3-month history of heartburn. The patient has type 2 diabetes mellitus and pernicious anemia. She also has cholelithiasis, for which she has refused surgical treatment. Medications are metformin, atorvastatin, and monthly injections of vitamin B12 (cyanocobalamin). Hemoglobin A1c obtained 30 days ago was 7.2%. Family history is significant for colon cancer in two first-degree relatives. The patient is 160 cm (5 ft 3 in) tall and weighs 86 kg (190 lb); BMI is 34 kg/m2. Which of the following historical findings is the strongest risk factor for gastric carcinoma in this patient?

97-year-old woman who resides in a skilled nursing care facility has had confusion for 12 hours. She did not recognize her family members when they came to visit her. She was admitted to the facility 3 weeks ago because of progressive difficulty rising from a chair to stand and unsteadiness while using her walker. She has hypertension, heart failure, and rheumatoid arthritis. Current medications include lisinopril, furosemide, and ibuprofen as needed for joint pain. Her temperature is 36.3°C (97.3°F), pulse is 92/min, respirations are 14/min, and blood pressure is 100/65 mm Hg. Mucous membranes are dry. Cardiopulmonary examination shows no abnormalities. Neurologic examination shows no focal findings. On mental status examination, she is not oriented to place or time. Serum studies show:

Urinalysis and a chest x-ray show no abnormalities. Which of the following is the most appropriate next step in management?

A 28-year-old woman comes to the physician for a follow-up examination 6 months after discharge from the inpatient psychiatric unit, where she was diagnosed with bipolar disorder. During hospitalization, lithium carbonate and quetiapine therapy was begun. Since discharge, she has been in regular outpatient psychotherapy and has been compliant with her medications. Today, she reports a 1-month history of frequent urination and mild sedation. She says her mood has been stable since discharge. She has no other history of serious illness. She appears alert. Physical examination shows an intention tremor of the upper extremities. Mental status examination shows a euthymic mood and reactive affect. Speech, language, and thought processes are normal. In addition to measurement of the patient’s serum lithium concentration, which of the following is the most appropriate next step in managemen

A previously healthy 22-year-old woman comes to the physician because of a 3-week history of intermittent episodes of stabbing pain in her right lower abdomen. Each episode lasts up to 2 hours; the most recent episode awakened her from sleep. She is currently in no pain. Menses occur at regular 28-day intervals. Her last menstrual period was 2 weeks ago and lasted 5 days. She is sexually active with one male partner and uses condoms consistently. Her temperature is 37.2°C (99°F), pulse is 68/min, respirations are 18/min, and blood pressure is 110/70 mm Hg. Examination of the abdomen shows no tenderness or distention. There is a 6-cm, mobile, right adnexal mass anterior to the uterus. Test of the stool for occult blood is negative. Her hemoglobin concentration is 11.2 g/dL, leukocyte count is 7000/mm3, and platelet count is 298,000/mm3. A urine pregnancy test is negative. Pelvic ultrasonography shows a partially cystic mass in the right ovary with a single echogenic nodule and decreased blood flow. Which of the following is the most appropriate next step in management?

A 37-year-old woman, gravida 2, para 2, comes to the physician for a routine health maintenance examination. Menses occur at regular 28-day intervals. Routine Pap smears have shown no abnormalities. She has no history of serious illness. Her mother had breast cancer at the age of 63 years, her maternal aunt had endometrial cancer at the age of 54 years, and her paternal grandmother had colon cancer at the age of 72 years. The patient is sexually active and monogamous with her husband and has been using an oral contraceptive for 8 years. She does not smoke cigarettes or drink alcohol. Her children are 9 and 11 years of age. She works as a nurse. Physical examination, including breast and pelvic examinations, shows no abnormalities. She is concerned about the history of cancer in her family and asks about a screening test for cancer. Which of the following is the most appropriate recommendation at this visit?

A clinical trial is conducted of a new drug-eluting coronary artery stent that does not require antiplatelet therapy for patency in animal models. Twenty patients who had non–ST elevation acute myocardial infarction are recruited to participate in this study; all patients have absolute contraindications for chronic anticoagulation and are not surgical candidates. This study design is most appropriate for evaluating which of the following?

 32-year-old woman who works as a nurse comes to the office because of a 4-month history of increasing pain and swelling of her ankles. Her ankles are stiff in the morning and become progressively painful and swollen by the end of her work shifts. She runs on a treadmill and lifts weights three times weekly, but her symptoms have prevented her from running during the past month. There is no history of trauma, and she has no other joint pain. She has hypothyroidism treated with levothyroxine. Examination of the ankles shows warmth and moderate effusions. There is no erythema. Active and passive range of motion of the ankles elicits mild pain. The remainder of the examination shows no abnormalities. X-rays of the ankles show no fractures or degenerative changes. Which of the following is the most appropriate next step in diagnosis?

A 57-year-old woman comes to the physician for a routine gynecologic examination. Two years ago, results of a complete blood count were within the reference ranges, and her total cholesterol concentration was 180 mg/dL. She feels well. She has had a 4.5-kg (10-lb) weight gain during the past 6 months. She takes no medications. Her last menstrual period was 4 years ago. She does not smoke cigarettes. She drinks two glasses of wine daily. Her temperature is 37.2°C (99°F), pulse is 68/min, respirations are 12/min, and blood pressure is 130/85 mm Hg. She is 168 cm (5 ft 6 in) tall and weighs 77 kg (170 lb); BMI is 27 kg/m2. Pelvic examination shows mild atrophy of the vaginal mucosa. Serum studies show:

Which of the following is the most appropriate next step to determine the cause of this patient’s increased cholesterol concentration?

A 2-year-old boy who is in the hospital has apnea 12 hours after undergoing surgical drainage of the left hip because of sepsis. His medications are intravenous vancomycin, cefotaxime, and morphine. After application of bag-valve-mask ventilation and administration of naloxone, the patient’s apnea resolves. Review of the hospital database shows that the patient’s morphine dose was too high. Which of the following is most likely to prevent recurrence of this type of error?

A 57-year-old man comes to the physician because he has coughed up blood once weekly for the past month. He has had an intermittent mild cough for 10 years. He has a history of hypertension well controlled with lisinopril and hyperlipidemia well controlled with pravastatin. He was treated for pneumonia six times during his 20s and 30s. He says he had “all of the usual childhood diseases.” There is no family history of serious illness. He does not smoke. He works as a teacher’s aide. His temperature is 37.3°C (99.1°F), pulse is 80/min, respirations are 14/min, and blood pressure is 138/84 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 99%. A few crackles are heard at the lung bases. A grade 1/6 systolic murmur is heard best at the upper right sternal border. A CT scan of the chest is shown. Which of the following is the most likely diagnosis?

A previously healthy 8-year-old boy is brought to the emergency department because of a 1-day history of increasingly severe abdominal pain. He has no history of serious illness and receives no medications. He appears well developed and well nourished. His temperature is 38.1°C (100.5°F), pulse is 100/min, and blood pressure is 90/70 mm Hg. Cardiopulmonary examination shows no abnormalities. Abdominal examination shows localized tenderness over the right lower quadrant; there is guarding at the McBurney point. Bowel sounds are decreased. Laboratory studies show a hemoglobin concentration of 12.5 g/dL (N=11.5–15.5) and leukocyte count of 14,500/mm3 (N=4500–13,500). Urinalysis shows no abnormalities. Which of the following is the most appropriate next step in management?

A previously healthy 47-year-old woman comes to the physician because of a 5-day history of an itchy rash. The rash initially began on her trunk but now has spread to her face, arms, and legs. She has not had fever, shortness of breath, fatigue, loss of appetite, or weight loss. She returned from a trip to Jamaica 2 days ago. She takes no medications and has no known drug allergies. She has had a peanut allergy since childhood and typically has shortness of breath and swelling of the lips when she eats peanuts. She does not recall ingesting peanuts on her trip but says that she ate food at the hotel. Her temperature is 36.9°C (98.4°F), pulse is 78/min, respirations are 14/min, and blood pressure is 110/80 mm Hg. Examination shows no abnormalities except for 1- to 2-cm, circular, blanched, raised urticarial lesions over the face, trunk, and upper and lower extremities; the rash is most prominent over the face, hands, and feet. Which of the following is the most appropriate next step in management?

A 7-year-old boy is brought to the office by his mother because she is concerned about his behavior at school since he began second grade 3 months ago. His teacher says he often fidgets and talks to his classmates when he has been told to be quiet. He misbehaves in language arts and spelling class but is well behaved during math and science classes. He has been sent to the principal’s office three times during the past month because of disruptive behavior. He says recess is his favorite part of school; he dislikes reading. His mother has no concerns about her son’s behavior at home. She says he has many friends in the neighborhood and enjoys sports activities. He has no history of serious illness and receives no medications. His paternal cousin has attention-deficit/hyperactivity disorder. The patient’s father dropped out of high school in 10th grade because of difficulty reading. During the examination, the patient is talkative and tells the physician about his new bicycle. Vital signs are within normal limits. Examination shows a mild eye-blink motor tic. His mother says the tic has occurred intermittently during the past 2 weeks. No other abnormalities are noted. Which of the following is the most likely diagnosis?

A 42-year-old woman, gravida 2, para 2, comes to the office because of a 1-day history of loss of clear, yellow vaginal fluid while walking; she has soaked two absorbent pads during this time. Two weeks ago, she underwent laparoscopic-assisted total vaginal hysterectomy for menorrhagia, dysmenorrhea, and adenomyosis. Intraoperatively, dissection of the bladder from the cervix was complicated by adhesions. She has mild asthma treated with an albuterol inhaler three to four times monthly. Both her pregnancies ended in low-transverse cesarean deliveries because of breech presentations. She has been taking ibuprofen four times daily and reports good pain control. Temperature is 37.8°C (100.0°F), pulse is 92/min, respirations are 16/min, and blood pressure is 128/78 mm Hg. On examination, the abdomen is nondistended and nontender. There is no blood over the perineum. Which of the following is the most likely cause of this patient’s current condition?

An asymptomatic 72-year-old woman comes for a follow-up examination after she was found to have an 80% stenosis of the right internal carotid artery. A new study has shown that endarterectomy for asymptomatic stenosis decreases the risk for stroke or death from 10% to 5% at 5 years (p<0.05). Which of the following is the best way to interpret this research for this patient?

An otherwise healthy 17-year-old girl is brought to the physician by her mother because of a 1-year history of monthly cramps that begin 3 days before the onset of menses and last 5 days. The cramps have increased in severity during the past 4 months, causing her to miss 1 to 2 days of school each month. Menses occur at regular 27- to 30-day intervals and last 4 to 5 days. Menarche was at the age of 14 years. She has never been sexually active. She is 165 cm (5 ft 5 in) tall and weighs 54 kg (118 lb); BMI is 20 kg/m2. Examination shows a nontender abdomen and normal external genitalia. Pelvic examination is limited because of a narrow vaginal introitus. Ultrasonography of the pelvis shows a normal uterus and ovaries. Which of the following is the most appropriate next step in management?

An 80-year-old woman comes to the physician because of two episodes of vision loss in her right eye that occurred yesterday. Each episode lasted 3 to 5 minutes. She also has a 6-month history of frontal headaches, fatigue, and aching in her right arm with exertion. She is otherwise asymptomatic. She has hypertension and osteoporosis. Her medications are metoprolol, lisinopril, alendronate, and calcium supplementation. She does not appear to be in acute distress. Her pulse is 72/min. Her blood pressure is 120/75 mm Hg in the right upper extremity and 155/85 mm Hg in the left upper extremity. Ophthalmologic and funduscopic examinations show no abnormalities. Peripheral pulses are 2+. Neurologic examination shows no focal findings. Her erythrocyte sedimentation rate is 85 mm/h. Carotid duplex ultrasonography shows stenosis of 20% to 40% of the right carotid artery and of more than 50% of the right subclavian artery. Which of the following is the most appropriate next step in management?

A 91-year-old man is brought to the emergency department by his wife because he collapsed at home after the onset of a headache. He has chronic obstructive pulmonary disease and claudication in his lower extremities. He underwent removal of bilateral cataracts 5 years ago. Current medications include metoprolol and an albuterol inhaler. He has an advance directive stating that he does not want any heroic, life-prolonging measures. He is intubated and mechanically ventilated. He is unresponsive to painful stimuli. Approximately 10 minutes after arrival, the cardiac monitor shows asystole. Which of the following is the most appropriate next step in management?

A 57-year-old man comes to the physician for an annual follow-up examination. He has hypertension, hyperglycemia, and hypercholesterolemia. He has had no claudication or chest pain. Current medications include atenolol, simvastatin, and lisinopril. He has smoked one-half pack of cigarettes daily for 40 years. He is 180 cm (5 ft 11 in) tall and weighs 77 kg (170 lb); BMI is 24 kg/m2. His temperature is 37.1°C (98.8°F), pulse is 72/min, respirations are 12/min, and blood pressure is 125/75 mm Hg. Pedal pulses are absent on the right. There is no tenderness. The right ankle brachial index is 0.8 (N>1), and the left ankle brachial index is 1. An ECG shows a normal sinus rhythm and borderline left ventricular hypertrophy. Laboratory studies show:

A comatose 2-year-old boy is brought to the emergency department by paramedics after his parents found him submerged in the family swimming pool for an unknown length of time. Cardiopulmonary resuscitation (CPR) at the scene was initiated by neighbors and continued by paramedics en route to the hospital. After a total of 20 minutes of CPR, a normal sinus rhythm is established. On arrival, the patient remains comatose. He is intubated, and mechanical ventilation is begun. At this time, arterial blood gas analysis on an Fio2 of 0.6 shows:

His serum sodium concentration is 135 mEq/L. This patient is at greatest risk for which of the following complications during the next 48 hours?

A 62-year-old man comes to the physician because of a 6-month history of midback pain, numbness and swelling of his legs, and fatigue. He has a 2-week history of swelling of his face and hands. Vital signs are within normal limits. Examination of the lower thoracic spine shows tenderness to percussion. There is 3+ edema of the face, hands, and lower extremities. Sensation to light touch and pinprick is decreased over the lower extremities. His serum creatinine concentration is 3.5 mg/dL. Serum protein electrophoresis shows monoclonal gammopathy. X-rays of the thoracic spine show lytic lesions in three vertebrae. Urinalysis is most likely to show which of the following sets of findings?