USMLE USMLE Certifications USMLE-STEP-2 Questions & Answers

• Question 711:

  A63-year-old man complains of sudden onset of right-sided headache while at work. He rapidly becomes confused and lethargic. On examination, he is hemiparetic and has bilateral Babinski signs. ACT scan of the head is shown in the figure. What is the patient most likely to have?

  

  A. an arteriovenous malformation

  B. a carotid occlusion

  C. hypertension

  D. an underlying malignancy

  E. abnormal clotting studies

  Correct Answer: C

  The history and physical examination of the patient described in the question suggest either an intracerebral hemorrhage or a completed ischemic stroke. The CT scan that accompanies the question demonstrates a large hemorrhage in the region of the right basal ganglia with a surrounding zone of edema and narrowing of the ventricle. Patients with intracerebral hemorrhage often have a preceding history of hypertension. Carotid occlusion, malignancy, arteriovenous malformation, and coagulopathy all are much less likely causes of this disorder. In general, only cerebellar hemorrhages and cerebral hemorrhages that are easily reached are surgically evacuated. Most intracerebral hemorrhages are managed with general supportive care.

• Question 712:

  A 73-year-old man has been experiencing increasing drowsiness and incoherence. He has a history of arrhythmias and has fallen twice in the past 2 weeks. There are no focal deficits on neurologic examination. Acontrast CT scan of the head is shown in the figure below. Which of the following is the treatment of choice?

  

  A. parenteral antibiotics

  B. antifungal therapy

  C. neurosurgical evacuation of the clot

  D. observation and a repeat CT scan in 1 month

  E. fibrinolytic therapy

  Correct Answer: C

  The CT scan shown in Figure demonstrates a smooth, biconvex lens-shaped mass in the periphery of the right temporoparietal region. This picture is characteristic of a subdural hematoma that is a result of laceration of veins bridging the subdural space. Unlike an epidural hematoma, which expands quickly and progresses rapidly to coma, a subdural hematoma is initially limited in size by increased intracranial pressure and expands slowly. Symptoms may follow the inciting trauma by several weeks. Altered mental status is often more prominent than focal signs and may progress from confusion to stupor to coma. Treatment consists of evacuation of the clot via burr holes. Antibiotics and antifungal agents have no role, and fibrinolytic therapy or delay in treatment could be harmful.

• Question 713:

  A 70-year-old man presents with shuffling gait, tremor, masked facies, and rigidity which have progressed over the last 9 months. Parkinson's disease is diagnosed. Which of the following is not true about Parkinson's disease?

  A. Over 1 million people in North America have Parkinson's disease.

  B. Mortality is higher in patients with Parkinson's disease when compared to age-matched controls.

  C. The classic triad of major signs of Parkinson's disease is memory loss, rigidity, and akinesia.

  D. The tremor in Parkinson's disease is typically an intention tremor.

  E. Over 90% of patients with Parkinson's disease have a good initial response tolevodopa.

  Correct Answer: D

  Deficiency of dopamine primarily is responsible for the signs and symptoms of Parkinson's disease. Specifically, the loss of dopamine from the substantia nigra is thought to be primarily responsible for the akinesia and rigidity. Tremor, akinesia, and rigidity are the classic triad of signs seen in Parkinson's disease. The tremor typically is a resting tremor; often a "pill rolling" tremor is seen in the hand. Well over 90% of patients with Parkinson's disease do have a good initial response to levodopa

• Question 714:

  A 70-year-old man presents with shuffling gait, tremor, masked facies, and rigidity which have progressed over the last 9 months. Parkinson's disease is diagnosed. In this patient, which neurotransmitter deficiency primarily is responsible for his symptoms?

  A. acetylcholine

  B. epinephrine

  C. norepinephrine

  D. dopamine

  E. cortisol

  Correct Answer: D

  Deficiency of dopamine primarily is responsible for the signs and symptoms of Parkinson's disease. Specifically, the loss of dopamine from the substantia nigra is thought to be primarily responsible for the akinesia and rigidity. Tremor, akinesia, and rigidity are the classic triad of signs seen in Parkinson's disease. The tremor typically is a resting tremor; often a "pill rolling" tremor is seen in the hand. Well over 90% of patients with Parkinson's disease do have a good initial response to levodopa

• Question 715:

  Which of the following is a useful clue to the diagnosis of Legionella pneumonia?

  A. diarrhea

  B. rash

  C. pedal edema

  D. elevated serum glucose

  E. photophobia

  Correct Answer: A

  The spectrum of infection with Legionella organisms ranges from asymptomatic seroconversion to Pontiac fever (a flu-like illness) to full-blown pneumonia. Cough is usually nonproductive initially. Malaise, myalgia, and headache are common. The diagnosis of Legionella infection is suggested by extrapulmonary signs and symptoms, including diarrhea, abdominal pain, azotemia, and hematuria.

• Question 716:

  A60-year-old previously healthy man presents with massive rectal bleeding. Which of the following is the most likely diagnosis?

  A. diverticulosis of the colon

  B. ulcerative colitis

  C. external hemorrhoid

  D. ischemic colitis

  E. carcinoma of the colon

  Correct Answer: A

  The causes of lower gastrointestinal (GI) bleeding include hemorrhoids and anal fissure diverticulosis, carcinoma, vascular ectasia, colitis, and polyps. Carcinoma of the colon usually causes chronic GI bleeding, resulting in anemia. Diverticulosis and vascular ectasia are common causes of massive GI bleeding in the elderly patient. Inflammatory bowel disease can also cause massive GI bleeding but is more frequent in younger age group patients. Most patients with ischemic colitis will be quite sick and will have had symptoms before the onset of bleeding.

• Question 717:

  A 24-year-old man runs a marathon on an unusually hot and muggy day. Several hours later he becomes ill with fever, weakness, and painful swollen legs and passes dark brown urine. Which of the following is a common finding with this disorder?

  A. Urine orthotoluidine (Hematest) reaction will be negative.

  B. Serum will be pink.

  C. Serum creatine phosphokinase levels will be elevated.

  D. Serum haptoglobin levels will be elevated.

  E. Serum potassium levels will be lowered.

  Correct Answer: C

  The clinical features of the patient described in the question are characteristic of rhabdomyolysis with myoglobinuria. Skeletal muscle injury releases large amounts of myoglobin into the circulation, and myoglobinuria produces a positive orthotoluidine reaction. Because myoglobin is quickly cleared from serum by the kidneys, the serum does not turn pink, as it does with hemoglobinemia. Muscle damage leads to elevated creatine phosphokinase levels and hyperkalemia. Myoglobin does not bind to haptoglobin as does hemoglobin, so serum haptoglobin levels are normal. The major complication of rhabdomyolysis is acute renal failure.

• Question 718:

  A32-year-old woman is referred to you by her dermatologist for further evaluation. She developed these changes gradually in the last year. Her hands are seen in Figure. What other associated disease is most likely?

  

  A. acquired immune deficiency syndrome (AIDS)

  B. Addison's disease

  C. lymphoma

  D. primary biliary cirrhosis

  E. Hashimoto's thyroiditis

  Correct Answer: E

  Up to 30% of cases of acquired vitiligo are associated with thyroid disease, especially Hashimoto's thyroiditis. It also may occur with pernicious anemia, diabetes, and other autoimmune disorders. Vitiligo has not been reported with AIDS. Addison's disease, lymphoma, and biliary cirrhosis can be associated with hyperpigmentation.

• Question 719:

  A59-year-old woman who lives independently and had been healthy, presents to the emergency department with cough and fever. She related she was well until 2 days before when she noted onset of fever, chills, and cough productive of yellow sputum. On examination, you note a tired appearing woman with BP of 160/90, pulse of 105, and respiratory rate of 32. You start her on ceftriaxone and azithromycin and admit her to the hospital. Which of the following factors is a poor prognostic sign in community acquired pneumonia?

  A. age less than 60

  B. systolic BP = 160 mmHg

  C. leukocytosis = 15,000

  D. respiratory rate = 32

  E. mycoplasma pneumonia infected

  Correct Answer: D

  Respiratory rate >30 is a poor prognostic sign in community-acquired pneumonia. Other patient factors include age greater than 65 years, coexisting illness such as cancer, liver disease, congestive heart failure (CHF), renal disease, systolic BP less than 90 mmHg, temperature greater than 40°C. Laboratory finding s associated with poor prognosis include arterial pH <7.35, BUN >30, sodium less than 130, glucose >250, and hematocrit <30%. These factors are often used to calculate the PORT (Pneumonia Outcomes Research Team) pneumonia severity index score which can be an aid in making treatment decisions. S. pneumoniae, Legionella, and S. aureus are the pathogens associated with poor prognosis, not Mycoplasma.

• Question 720:

  A 54-year-old man presents to the emergency department complaining of epigastric discomfort, which began while he was walking his dog after dinner about one-half hour earlier. He has not received medical care for several years. On examination, he is moderately obese and in obvious discomfort and seems restless. His BP is 160/98 mmHg, and his examination is otherwise unremarkable. His ECG is seen in Figure below:

  

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

  A. trial of antacid immediately

  B. reassurance and arrange outpatient follow-up

  C. arrange for cardiac intensive care bed

  D. begin thrombolytic therapy in the emergency department

  E. arrange for urgent echocardiogram

  Correct Answer: D

  This ECG reveals ST-segment elevation in II, III, and AVF, indicating acute injury of the inferior wall of the myocardium. Inferior wall ischemia can be perceived as pain in the epigastric area. Anterolateral myocardial infarction would show loss of R-wave progression in V4 through V6. Pericarditis would show diffuse ST segment elevation in limb and precordial leads. Although his symptoms could suggest gastroesophageal reflux, this ECG shows this a cardiac event. Costochondritis is not present by examination. When ST segment elevation is present, a patient should be considered a candidate for reperfusion therapy or primary percutaneous intervention (PCI) such as angioplasty and stenting. If no contraindications are present and PCI is unavaliable, thrombolytic therapy should ideally be initiated within 30 minutes, right in the emergency department. The goal of both thrombolysis and PCI is prompt restoration of coronary arterial patency. Thrombolytic therapy can reduce the risk of in- hospital death by up to 50% when administered within the first hour of symptoms, so time is of the essence. Arranging for a bed may waste time for limiting infarct size. The ECG would obviously preclude the other two options: immediate trial of antacid or reassurance and arranging outpatient follow-up.