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

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 311:

  A father you are treating for hyperlipidemia brings his 23-month-old son into your clinic for a routine checkup. He reports that he and his wife are separated and that he is uncertain if the child has received appropriate medical care. The child has no known medical problems and is not a member of any high- risk population. The child is new to your clinic, but the father produces an immunization record which states the child has received the following vaccines: diphtheria, tetanus, and acellular pertussis at 2, 5, and 7 months; hepatitis B vaccine at birth, 2 months, and 7 months; H. influenzae type b at 2 and 5 months; inactivated poliovirus at 2, 5, and 7 months; and a measles, mumps, and rubella vaccine at 12 months. You tell the father that the child has received some of the recommended immunizations late, but that the child is adequately protected.

  The infant should receive varicella immunization in addition to which of the following vaccinations?

  A. hepatitis A vaccine now, and again in 6 months
  B. pneumococcus vaccine now, and again in 6 months
  C. oral polio vaccine now
  D. Diptheria, Tetanus, acellular Pertussis (DTaP) vaccine now
  E. oral typhoid vaccination now
  D. Diptheria, Tetanus, acellular Pertussis (DTaP) vaccine now

  ---

  Explanation

  The fourth DTaP must be at least 6 months later than the third dose. Hepatitis Avaccine is recommended in some high-risk communities, but it is not recommended for all children. Pneumococcus vaccine for children not previously immunized by 23 months should receive two doses 8 weeks apart. Oral polio vaccine should not be used when inactivated poliovirus is available.

• Question 312:

  Which of the following medications may be appropriate for treating children with attention deficit disorder?

  A. lithium
  B. bupropion
  C. alprazolam
  D. propranolol
  E. perphenazine
  B. bupropion

  ---

  Explanation

  The antidepressant bupropion has been found effective for treating some cases of attention deficit disorder and offers help to those children not responsive to the usual treatment with stimulants (methylphenidate, pemoline). The remaining choices have not been found useful in treating this condition. They are lithium, a mood stabilizer; alprazolam, a benzodiazepine anxiolytic; propranolol, a betablocker; and perphenazine, an antipsychotic.

• Question 313:

  A 58-year-old woman with a history of chronic paranoid schizophrenia, who has been continuously treated with antipsychotics for the past 20 years, lives in a community-based residential facility. She has recently suffered an increase in auditory hallucinations, and her haloperidol dose has been increased from 2.5 to 10 mg/day. Four days later, she is brought by a visiting nurse to the emergency room, where she presents with confusion, marked flexor and extensor rigidity in her legs and arms, and a temperature of 103.5°F. Her blood pressure is160/120 mmHg, her pulse is 120/min and irregular. Which of the following is most likely to be an effective treatment for this condition?

  A. intramuscular haloperidol
  B. oral bromocriptine
  C. intramuscular lorazepam
  D. intramuscular benztropine
  E. oral propranolol
  B. oral bromocriptine

  ---

  Explanation

  The most effective treatments for the extremely serious, potentially fatal complication of antipsychotic treatment called NMS are oral bromocriptine, a dopaminergic agonist, and intravenous or oral dantrolene, a skeletal muscle relaxant. Afurther increase in the patient's haloperidol dose would likely worsen her NMS. While the anticholinergic effects benztropine may alleviate some of the neuroleptic- induced muscular dystonia associated with the syndrome, and lorazepam may help relax the muscle rigidity, they are not likely to be life saving, and propranolol is not an effective medication in the treatment of NMS.

• Question 314:

  A 3-year-old child recovers from a severe episode of bloody diarrhea, hemolysis, and uremia. The child's case is linked to other cases across the country by statistical association with consumption of hamburgers obtained from a nationwide supplier of ground beef. Which of the following is the best method for preventing this illness in the general population?

  A. cooking ground beef to be well done, and thoroughly washing fruits and vegetables
  B. regulations enforcing worker hygiene in the workplace
  C. a testing program for enteric disease in Livestock
  D. regulations enforcing sanitary conditions in slaughterhouses
  E. a ban on imported meats and produce
  A. cooking ground beef to be well done, and thoroughly washing fruits and vegetables

  ---

  Explanation

  The illness described is consistent with hemolytic uremic syndrome associated with E. coli 0157:H7 infection. E. coli 0157:H7 is the most common strain found of the enterohemorrhagic E. coli (EHEC) group. Although its most common reservoir is thought to be in cattle, it has been found in other livestock. The usual mode of exposure is contamination of beef. The problem is compounded significantly when beef is ground and mixed in bulk. Testing and elimination programs do not appear sensitive enough to eliminate exposure, although active research in the area continues. In addition, there are many other outbreaks associated with fresh vegetables, bean sprouts, and unpasteurized juices. It is hypothesized that these are due to contamination with human or animal waste. Since the organism is killed by heating, thorough cooking of ground beef products, avoidance of contamination of fresh foods with raw meat, and washing of produce intended to be served fresh is the most practical intervention. Currently, this remains the most practical advice to give the public.

• Question 315:

  Amother brings in her 3-year-old girl because she felt a smooth mass on the left side of her belly when she was giving her a bath. Which of the following is the most likely diagnosis?

  A. Wilms tumor
  B. neuroblastoma
  C. acute lymphoblastic leukemia
  D. Hodgkin's disease
  E. hepatoblastoma
  A. Wilms tumor

  ---

  Explanation

  Wilms tumor is a malignant embryonal neoplasm of the kidney. It is the second most common solid tumor of childhood. Girls are affected more frequently than boys (2:1). The incidence of Wilms tumor peaks at 13 years of age. The classic presentation is a painless abdominal mass that is usually hard, smooth, and unilateral. Hematuria occurs in 1225% of children with Wilms tumor, and hypertension has been reported in up to 60% of patients. Aniridia or hemihypertrophy may be observed in patients with Wilms tumor.

• Question 316:

  A 45-year-old man presents to the physician's office complaining of dysphagia and retrosternal pressure and pain of 2-year duration. The symptoms have worsened over the last 3 months. He has a 30 packyear smoking history and drinks beer on weekends. Vital signs include a BP of 150/90 mmHg, pulse rate of 90/ min, and respiratory rate of 12/min, with a normal temperature. Examination reveals a thin man with a normal heart, lung, and abdomen examination. An esophagogram reveals a 6-cm, smooth, concave defect in the midesophagus with sharp borders. Esophagoscopy reveals intact overlying mucosa and a mobile tumor.

  Which of the following is the most appropriate next step?

  A. repeat esophagoscopy with biopsy
  B. thoracotomy with extramucosal resection
  C. thoracotomy with esophageal resection
  D. radiation therapy
  E. chemotherapy
  B. thoracotomy with extramucosal resection

  ---

  Explanation

  Leiomyomas are the most common benign tumors of the esophagus. They are intramural, occur between 20 and 50 years of age, and may be symptomatic when over 5 cm. Symptoms may include dysphagia and retrosternal pressure and pain. Esophagogram shows characteristic features of a smooth concave defect with sharp borders. Esophagoscopy is indicated to rule out carcinoma. These tumors are mobile, with intact overlying mucosa. Biopsy should not be performed so that subsequent extramural resection can be performed without complication. Excision is recommended for symptomatic leiomyomas or those greater than 5 cm.

• Question 317:

  A 70-year-old female with chronic paranoid schizophrenia presents to the ER acutely confused with visual hallucinations. Her skin is warm and dry and her heart rate is 110 beats per minute. Her group home nurse tells you that the patient had been complaining of having a dry mouth and having difficulty initiating urination this past week.

  Which of the following is the most likely cause for this presentation?

  A. psychotic exacerbation of schizophrenia
  B. urinary tract infection
  C. Alzheimer dementia
  D. anticholinergic delirium
  E. myocardial infection
  D. anticholinergic delirium

  ---

  Explanation

  Acute confusion with visual hallucinations would be characteristic of a delirium. Warm and dry skin, tachycardia, dry mouth, constipation, and urinary retention are anticholinergic side effects. Many antipsychotics are anticholinergic, and when Parkinsonian EPS present, anticholinergic medicines are often added to reverse these side effects. These anticholinergic effects can be additive and can cause delirium.

• Question 318:

  A22-year-old G3P1102 is admitted to the Labor and Delivery ward at 28 weeks' gestation complaining of watery vaginal discharge. You confirm the diagnosis of preterm premature rupture of amniotic membranes (PPROM). Fetal monitoring demonstrates reassuring fetal heart tones and no contractions are noted. The patient is understandably concerned and asks you why this happened and what this means for her pregnancy. Which of the following should you tell her?

  A. The incidence of PPROM is directly correlated to maternal age.
  B. Most patients with PPROM before 30 weeks will remain pregnant until at least 34 weeks.
  C. Management at home is a reasonable option for most patients until the onset of contractions.
  D. Patients with bacterial vaginosis are at increased risk for PPROM during pregnancy.
  E. Pulmonary hypoplasia is a common complication of PPROM at this gestational age.
  D. Patients with bacterial vaginosis are at increased risk for PPROM during pregnancy.

  ---

  Explanation

  Preterm premature rupture of membranes is a relatively common condition, affecting 318.5% of all pregnancies. It is estimated that 30% of all preterm deliveries result from PPROM. There are multiple etiologies for PPROM, including ascending vaginal infection. Carriers of GBS, bacterial vaginosis, and gonorrhea are all at increased risk for PPROM. Maternal age is not a risk factor, nor is parity, maternal weight, maternal weight gain, or trauma. According to most experts, patients with this condition should be managed in the hospital due to the high risk for amniotic infection, preterm labor, and umbilical cord compression or prolapse. Pulmonary hypoplasia and fetal compression malformations are seen when rupture of membranes occurs in the previable period (less than 24 weeks). The duration of latency (time from rupture of membranes to delivery) varies inversely with gestational age. In other words, at term, labor generally begins within hours. However, even at 28 weeks, up to 90% of patients will go into labor within 1 week.

• Question 319:

  A 4-day-old infant presents with yellow discoloration of the skin and sclera. The baby was born at term by a normal vaginal delivery. Pregnancy was uncomplicated; there were no risk factors for sepsis and no history of maternal alcohol or drug use. The baby is breast-fed and has been nursing every 2 hours, about 10 minutes at each breast. The bilirubin level is 15 mg/dL (all unconjugated), the hematocrit is 45%, and the Coombs test is negative. Which of the following is the most likely diagnosis?

  A. congenital biliary atresia
  B. isoimmune hemolytic disease
  C. Crigler-Najjar syndrome
  D. breast milk jaundice
  E. breast-feeding jaundice
  E. breast-feeding jaundice

  ---

  Explanation

  The most common causes of neonatal cholestasis are extrahepatic biliary atresia and idiopathic neonatal hepatitis. Infants usually develop icterus by 26 weeks of age. They have conjugated hyperbilirubinemia, dark urine, and acholic stools. At time of presentation, there is usually hepatomegaly, as well as pruritis, splenomegaly, and ascites. The use of RhoGAM (anti-D gamma globulin) has reduced the incidence of Rh sensitization and resulting jaundice. ABO incompatibility can also cause a milder form of isoimmune hemolytic disease and jaundice. It is more common in infants with blood types Aand B born to mothers with blood type O. Anemia is usually present; direct Coombs test is weakly positive; and indirect Coombs test is positive. Crigler-Najjar syndrome is autosomal recessive; there is usually marked hyperbilirubinemia (240 mg/dL) in an otherwise asymptomatic infant. The high levels result in kernicterus. Physiologic jaundice is the most common cause of unconjugated hyperbilirubinemia; it is characterized by peak bilirubin level of <13 mg/dL on day of life 35, decrease to normal within 2 weeks. In breast-fed infants, this is often exaggerated, with levels >13 mg/dL. This occurs in 1025% of breastfed infants, as opposed to 47% of formulafed infants. It is known as "breast-feeding" jaundice. "Breast-milk" jaundice, develops after the first week of life, peaking between the 2nd and 3rd week to 1020 mg/dL. The cause of this has not been established.

• Question 320:

  A 70-year-old man is admitted to the ICU after repair of an abdominal aortic aneurysm. He has a prior history of hypertension and mild congestive heart failure, which were adequately controlled with digoxin and diuretics. To facilitate perioperative management, a Swan-Ganz (multilumen pulmonary artery) catheter was inserted in the operating room. During the first few hours postoperatively, the patient is noted to have a blood pressure of 140/70 mmHg, heart rate of 110/min, flat neck veins, a pulmonary arterial wedge pressure of 9 mmHg, and poor urine output. Which of the following is the most appropriate next step in management of this patient?

  A. IV furosemide
  B. a bolus of IV crystalloid
  C. a dopamine infusion
  D. a nitroprusside infusion
  E. IV digoxin administration
  B. a bolus of IV crystalloid

  ---

  Explanation

  In the initial postoperative period, the patient has a low pulmonary artery wedge pressure and poor urine output. Renal perfusion is compromised by hypovolemia, with subsequent inadequate preload and decreased cardiac output. The appropriate therapeutic intervention at this time is further IV fluid resuscitation. Diuretics are contraindicated in the patient with hypovolemia and are unlikely to improve urine output in the face of inadequate renal perfusion. A dopamine infusion or digoxin may improve cardiac contractility but will not result in improvement in cardiac output unless there is adequate preload. In a hypovolemic patient, nitroprusside will result in a significant drop in blood pressure. After receiving a fluid bolus, the patient develops distended neck veins and an elevated pulmonary wedge pressure, indicating biventricular dysfunction with increased left ventricular end-diastolic pressure, and increased left ventricular endsystolic volume. Cardiac output is low, and urine output has not improved. In a patient with a history of hypertension, this clinical picture is often caused by increased afterload. Afterload reduction can be obtained with a nitroprusside infusion.