USMLE USMLE-STEP-2 Online Practice Questions and Exam Preparation

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 131:

  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
  C. hypertension

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  Explanation

  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 132:

  A 37-year-old pregnant woman with type 2 diabetes mellitus and chronic hypertension is 35 weeks' pregnant. Which of the following is the best test to screen for fetal well-being?

  A. nonstress test (NST)
  B. oxytocin challenge test
  C. amniocentesis
  D. fetal movement counting
  E. fetal biophysical profile
  E. fetal biophysical profile

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  Explanation

  Of the choices listed, a biophysical profile is the best assessment of fetal well-being. This assesses multiple fetal variables: breathing movement, body or limb movements, tone and posture, fetal heart rate pattern, and amniotic fluid volume. A NST, oxytocin challenge test, and fetal movement counts assess only one determinant of fetal well-being. An amniocentesis has no value in assessing fetal well- being, but may be appropriate to determine fetal lung maturity if induction of labor before 40 gestational weeks is indicated because of her chronic illnesses. Fetal Doppler studies to assess systolic:

  diastolic (SD) ratio may be a better test of fetal well-being and a significant decrease or reversal of the ratio is an indication for delivery.

• Question 133:

  A 55-year-old male who is a former IV drug user presents with jaundice, ascites, and leg edema. A CT scan of the abdomen reveals a malignant-appearing mass in the liver. According to the above findings of patient having hepatitis virus, select the most likely type of viral hepatitis.

  A. hepatitis A
  B. hepatitis B
  C. hepatitis C
  C. hepatitis C

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  Explanation

  Hepatitis A is transmitted almost exclusively by the fecal-oral route. Large outbreaks have been linked to contaminated food products. Intrafamily and intrainstitutional spread also is common. Clinical severity usually is mild, and hepatitis A does not progress to chronicity. Hepatitis C more commonly progresses to chronicity (5070% develop chronic hepatitis and 8090% of these patients have evidence for chronic infection). Hepatitis C can lead to cirrhosis and hepatocellular carcinoma. Chronicity occurs in only 110% of patients with hepatitis B

• Question 134:

  A 51-year-old woman presents to the physician's office with a 2-month history of a right breast bloodtinged nipple discharge. Past history is unremarkable. Family history is positive for postmenopausal breast cancer in a maternal grandmother. Examination reveals no palpable masses or regional adenopathy, but a serous discharge is easily elicited from a single duct in the right breast. Bilateral mammograms show no abnormalities. Cytology from the discharge was not diagnostic. A ductogram was ordered, and the results are shown in the figure below.

  

  Which of the following is the most likely diagnosis?

  A. invasive carcinoma
  B. intraductal carcinoma
  C. intraductal papilloma
  D. fibrocystic disease
  E. duct ectasia
  C. intraductal papilloma

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  Explanation

  The most common cause of a nipple discharge is an intraductal papilloma. Galactography can often demonstrate a filling defect in the terminal ducts as is demonstrated in the figure. Duct ectasia may also cause a discharge, but the discharge is usually thick and pasty. Carcinoma is an uncommon cause of nipple discharge. The next step in management would be excision of the terminal duct containing the papilloma. Repeat cytology would not be useful because a negative result does not preclude biopsy.

  Observation would not be prudent, because a diagnosis of arcinoma must be excluded, and the papilloma may enlarge, requiring a more extensive operation at a later date. A more extensive operation, such as a central lumpectomy or mastectomy, would be unnecessary because the lesion is benign.

• Question 135:

  A75-year-old man is brought to the emergency department by his family for evaluation of jaundice. He complains of pruritus of 2 weeks' duration and a recent 10-lb weight loss. On examination, he is deeply jaundiced and has a nontender, globular mass in the right upper quadrant of the abdomen that moves with respiration. For above patient with jaundice, select the one most likely diagnosis.

  A. hepatitis A
  B. hemolysis
  C. choledocholithiasis
  D. biliary stricture
  E. choledochal cyst
  F. pancreatic carcinoma
  G. liver metastases
  H. cirrhosis
  I. pancreatitis
  F. pancreatic carcinoma

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  Explanation

  Pancreatic carcinoma occurs in the head of the gland in 75% of cases. About 75% of the patients with carcinoma in the head of the pancreas present with obstructive jaundice, weight loss, and, in the presence of advanced disease, abdominal pain.

• Question 136:

  Jehovah's Witnesses usually refuse to consider a recommended blood transfusion. A 5-yearold child with hemophilia and dangerously low hemoglobin levels needs such a transfusion, but the Jehovah's Witness parents refuse to accept the recommendation. How are principles of autonomy best resolved?

  A. The hospital's representatives respect the parents' right to consent and support their refusal.
  B. The physician explains the need, in simple words, to the child who refuses the transfusion.
  C. The hospital requests a local court to exercise the rights of the child through the appointment of a surrogate guardian.
  D. The local court gives the physician the right to decide if the transfusion is warranted.
  E. The hospital Chaplain is usually given the final authority in these matters.
  C. The hospital requests a local court to exercise the rights of the child through the appointment of a surrogate guardian.

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  Explanation

  The law has generally recognized that the parents do not necessarily exercise autonomy appropriately on behalf of their child. It also recognizes that children cannot exercise autonomy for themselves, and that children should not be required to make complicated decisions about their own care. For children, and for adults who are unable to make medical decisions, a surrogate decision maker is normally named by a court of appropriate jurisdiction.

• Question 137:

  A 12-year-old girl has had a sore throat over 2 days. She now has a fever of 39.5°C and has difficulty opening her mouth, swallowing, or speaking. Her throat can be visualized with difficulty, the right tonsil is significantly more enlarged than the left, and the uvula is displaced to the left side. Which of the following is the most likely diagnosis?

  A. retropharyngeal abscess
  B. acute uvulitis
  C. peritonsillar abscess
  D. acute pharyngitis
  E. lateral pharyngeal abscess
  C. peritonsillar abscess

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  Explanation

  This is a classic presentation for a peritonsillar abscess. Development of a peritonsillar abscess is usually preceded by acute pharyngotonsillitis, followed by development of severe throat pain and trismus. It is usually caused by group A hemolytic Streptococci or oral anaerobes in preadolescent or adolescent patients. Speech is often with a "hot potato" voice. The affected tonsil is enlarged causing the uvula to be pushed to the other side. Antibiotics (penicillin) and incision and drainage are usually required.

  Retropharyngeal abscess is usually a complication of bacterial pharyngitis in younger children under age 34 years. It is caused by infection and further suppuration of nodes in the retropharyngeal area. Symptoms include high fever, difficulty swallowing, feeding refusal, hyperextension of the head, and drooling. There is bulging of the posterior pharyngeal wall; diagnosis can be confirmed by widening of the retropharyngeal space on x-ray. With lateral pharyngeal abscess there is bulging of the lateral pharyngeal wall. Acute uvulitis is caused by group Ahemolytic Streptococci and H. influenzae type B, often in association with tonsillitis and uvulitis.

• Question 138:

  A 65-year-old woman presents to the physician's office for evaluation of an abnormal screening mammogram. She denies any breast masses, nipple discharge, pain, or skin changes. Past history is pertinent for hypertension. Family history is positive for postmenopausal breast cancer in a sister. She has a normal breast examination and no axillary adenopathy. The remainder of her examination is unremarkable. An MLO view of the right breast is shown in Figure along with a magnification view of the craniocaudal (CC) film

  

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

  A. observation, with repeat mammogram in 6 months
  B. observation, with repeat mammogram on an annual basis
  C. biopsy
  D. lumpectomy, radiation therapy, and SLN biopsy
  E. total mastectomy
  C. biopsy

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  Explanation

  The mammographic appearance is most consistent with DCIS with or without an invasive component. The calcifications of DCIS are clustered, pleomorphic, irregular, and linear, and may be associated with a mass representing an invasive carcinoma. LCIS does not usually present with calcifications. Cystosarcoma phyllodes presents as a mass, often indistinguishable from a fibroadenoma. An involuting fibroadenoma often presents as a mass with large, coarse calcifications, indicating its benignity. Milk of calcium will often layer differently in the CC and mediolateral projections, suggesting fluid with calcium. The next step in management is to obtain a biopsy, preferably a core needle biopsy, for histologic confirmation and to evaluate for invasive disease. Observation is not recommended because these calcifications appear malignant. All other choices (i.e., lumpectomy or total mastectomy) are not indicated until a diagnosis by biopsy is obtained.

• Question 139:

  A 25-year-old woman presents with a recurrent depression, and says she has taken many antidepressant medications from several different classes of drugs in the past. Which of the following atypical antidepressants is a presynaptic alpha-2 receptor noradrenergic antagonist and a 5-HT2 and 5-HT3 receptor serotonergic antagonist?

  A. bupropion
  B. trazodone
  C. nefazodone
  D. venlafaxine
  E. mirtazapine
  E. mirtazapine

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  Explanation

  Mirtazapine is a tetracyclic antidepressant that has both presynaptic alpha-2 receptor noradrenergic antagonist properties and 5-HT2 and 5-HT3 receptor serotonergic antagonist properties, which, taken together, result in a net increase in both noradrenergic and serotonergic neurotransmission. Bupropion may exert its antidepressant effects by acting on the noradrenergic system, but its method of action is currently being investigated. Trazodone and nefazodone are combined serotonin reuptake inhibitors and 5- HT2 serotonin antagonists. Venlafaxine is a combined norepinephrine and serotonin reuptake inhibitor

• Question 140:

  A dentist asks you to evaluate a 42-year-old woman before tooth extraction. Which of the following is the prophylactic antibiotic of choice for dental procedures?

  A. amoxicillin
  B. vancomycin
  C. cephalexin
  D. penicillin
  E. clindamycin
  A. amoxicillin

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  Explanation

  Guidelines for antibiotic prophylaxis of infective endocarditis (IE) underwent a major revision in 2007. Prophylaxis is now only recommended for those patients at highest risk of IE including patients with a prosthetic valve, history of IE, cardiac transplant patients that develop valvulopathy, cyanotic congenital heart disease that remains unrepaired, cyanotic congenital heart disease that has been repaired with a prosthesis during the first 6 months after the procedure or if a defect remains at the site of the prosthesis after 6 months. Congestive heart failure, an S4 gallop, and diabetes do not increase risk. Recommended antibiotic coverage for high-risk patients before dental procedures is amoxicillin 2 g PO 1 hour before the procedures. Penicillin- allergic patients can receive clarithromycin, cephalexin, cefadroxil, or clindamycin as prophylaxis. Streptococci and S. aureus are responsible for the majority of community- acquired native valve endocarditis cases.

  In IV drug abusers, S. aureus is responsible for more than 50% of cases, and Candida and Pseudomonas for about 6% each. Patients with prior endocarditis are at high risk. Bacterial endocarditis carries a mortality rate of about 25%, and prevention is of paramount importance. In S. aureus endocarditis in injection drug users, mortality is only 1015%. As many as 40% of cases occur without underlying heart disease. VSD, patent ductus arteriosus, and tetralogy of Fallot are most commonly associated;

  whereas, ASD is rarely a predisposing factor.