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

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 611:

  A 10-year-old boy comes to your office in the winter with a sore throat he has had for 2 days. In addition, he has had fever, headache, and abdominal pain. He does not have any allergies to medications. On examination, he has a temperature of 38.6°C, an ery thematous pharynx, and tender cervical adenopathy. Arapid screening test for group Astreptococcus is performed and is positive. Which of the following would be the most appropriate antimicrobial agent?

  A. erythromycin
  B. penicillin
  C. trimethoprim-sulfamethoxazole
  D. azithromycin
  E. cefaclor
  B. penicillin

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  Explanation

  Penicillin remains the drug of choice for treatment of streptococcal pharyngitis. Amoxicillin, macrolides, and cephalosporins are acceptable alternatives.

• Question 612:

  A48-year-old G5P5 woman has genuine stress incontinence (GSI). Kegel exercises have not helped, and her incontinence is gradually worsening. Her urethrovesical junction (UVJ) is prolapsed into the vagina, and her urethral closure pressure is normal. Which of the following procedures will most likely cure her incontinence?

  A. retropubic urethropexy
  B. anterior colporrhaphy
  C. suburethral sling procedure
  D. needle suspension of paraurethral tissue
  E. paraurethral collagen injections
  A. retropubic urethropexy

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  Explanation

  In a patient with GSI, a retropubic approach offers the best long-term cure of the incontinence. The Burch procedure and the Marshall- Marchetti-Krantz procedure are the most common retropubic procedures. With an anterior colporrhaphy, plication sutures are placed at the UVJ in an effort to support and elevate it. Long-term results are not as good as a retropubic urethropexy or a suburethral sling. Asuburethral sling procedure is used when urethral closing pressure is low, less than 20 cmH2O. A needle suspension procedure is most often done when there is associated genital prolapse with potential incontinence. Collagen injections at the UVJ have been attempted to obstruct the urethra partially. Incontinent patients who may benefit the most from collagen injections are those with intrinsic sphincter deficiency and a fixed bladder neck.

• Question 613:

  Select the appropriate incubation period of the Tatanus infectious disease of childhood.

  A. 16 days
  B. 78 days
  C. 810 days
  D. 1021 days
  E. 3050 days
  F. 120180 days
  B. 78 days

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  Explanation

  The incubation period for diphtheria is 17 days. The incubation period for chicken pox is 1021 days, average 14. Infectious mononucleosis, caused by the Epstein-Barr virus, has an estimated incubation period of 3050 days. The incubation period following infection by the mumps virus is usually 1618 days but, like chicken pox, may vary from 14 to 25 days. Pertussis has a shorter incubation period, usually 710 days, with a variation of 421 days. The usual period from contamination with tetanus spores to clinical symptoms is generally 68 days. For rubella, the incubation period is from 14 to 21 days, but usually ranges from 16 to 18 days.

• Question 614:

  For each item, select the ONE best lettered option that is most closely associated with it. Each lettered heading may be selected once, more than once, or not at all. A 48-year-old man is being evaluated for diabetes and hypertension. On examination, he has mandibular enlargement and large hands.

  A. Cushing's syndrome
  B. Addison's disease
  C. Klinefelter syndrome
  D. hyperparathyroidism
  E. hypothyroidism
  F. pheochromocytoma
  G. acromegaly
  H. diabetes insipidus
  I. diabetes mellitus
  J. polycystic ovarian disease
  G. acromegaly

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  Explanation

  Acromegaly is caused by oversecretion of growth hormone, usually from a pituitary adenoma. Clinical manifestations are indolent, often not diagnosed for 10 or more years. Acral bony overgrowth leads to frontal bossing, increased hand and foot size, and mandibular enlargement. Growth hormone excess also commonly affects the cardiovascular system. Upper airway obstruction with sleep apnea is present in up to 60% of patients.

• Question 615:

  Match the below medication with the potential blood dyscrasia side effect it can be associated with.

  Lithium

  A. leukocytosis
  B. thrombocytopenia
  C. agranulocytosis
  D. megaloblastic anemia
  E. lymphocytosis
  A. leukocytosis

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  Explanation

  Valproate can be associated with thrombocytopenia and platelet dysfunction especially at high doses. Leukocytosis is a common benign effect of lithium. Clozaril can cause agranulocytosis in 12% of patients. Agranulocytosis can be an idiosyncratic adverse event with carbamazepine

• Question 616:

  A 23-year-old woman presents with "skipped heartbeats" and on cardiac examination is found to have a midsystolic click followed by a late systolic murmur. Echocardiogram shows prolapse of the mitral valve.

  Which of the following is true about this condition?

  A. Mitral valve prolapse is present in up to 10% of the population.
  B. Mitral valve prolapse is more common in men.
  C. Prophylaxis against bacterial endocarditis is never recommended.
  D. Risk of pulmonary embolism is high.
  E. Ventricular arrhythmias do not occur.
  A. Mitral valve prolapse is present in up to 10% of the population.

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  Explanation

  Mitral valve prolapse can be diagnosed by auscultation and echocardiogram in as much as 10% of the population. They may be asymptomatic or complain of atypical chest pain, palpitation, shortness of breath, or weakness. An increasing number of complications are being recognized. Although they occur infrequently, they may be life threatening and demand careful evaluation of individuals at risk. Both supraventricular and ventricular arrhythmias occur, as may sudden death. Mitral insufficiency, if present, is usually insignificant but may progress and require valve replacement. There is an increased risk of infective endocarditis. Intraatrial thrombus formation may occur, predisposing to cerebral and peripheral embolism. Because the clot originates in the left atrium, however, pulmonary embolism does not occur more frequently in these patients.

• Question 617:

  A 2-year-old boy has had a purulent drainage from the right nostril for a week. He is afebrile and has had no associated symptoms, such as cough. Which of the following is the most likely diagnosis?

  A. sinusitis
  B. nasal polyps
  C. an upper respiratory infection
  D. a foreign body in the right nostril
  E. allergic rhinitis
  D. a foreign body in the right nostril

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  Explanation

  Children frequently insert foreign bodies into the nose. Initial symptoms are local obstruction, sneezing, and pain. Subsequently, there is swelling and infection leading to a purulent, malodorous, and often bloody discharge. The infection clears after removal of the foreign body. Nasal polyps cause obstruction of the nasal passages, hyponasal speech, and mouth breathing; gray, grape-like masses can be visualized on nasal examination. An upper respiratory infection is usually suggested by a careful history.

  Initial symptoms include a scratchy throat, followed by development of thin nasal discharge and sneezing. Myalgia, low- grade fever, headache, malaise, and decreased appetite may be present. By the 2nd or 3rd day, the discharge becomes thicker and more purulent. Cough is common. Symptoms usually resolve by 710 days. Adolescents with sinusitis may have classic symptoms of headache and sinus tenderness. In children, cough and nasal discharge are common; the cough is worse when supine. If upper respiratory infection symptoms persist without improvement for >10 days, sinusitis should be considered. A more acute form may occur, with a shorter duration and more severe symptoms such as fever >39°C, purulent nasal discharge, headache, and eye swelling. Children with allergic rhinitis present with sneezing, clear watery, rhinorrhea, and itching of the nose, palate, pharynx, and eyes. Itching, redness, and tearing of the eyes may be present. This occurs in response to exposure to an allergen such as pollen, mold spores, and animal or mite antigens

• Question 618:

  A 4-year-old previously healthy girl presents to the emergency department with a 24-hour history of rectal bleeding and dizziness. She has no other gastrointestinal symptoms. On examination, she appears pale. Her heart rate is 140 beats/min, and she has a 20 mmHg postural drop in systolic blood pressure. The child's abdomen is nondistended and nontender, and fresh blood and clots are in the rectal vault on rectal examination.

  Definitive management of this child should include which of the following?

  A. immediate exploratory laparotomy
  B. IV fluid resuscitation, transfusion with blood products as indicated, followed by a laparotomy with Meckel's diverticulectomy and ileal resection
  C. IV fluid resuscitation, followed by a colonoscopic polypectomy
  D. hemorrhoidectomy
  E. stool softeners and topical steroids
  B. IV fluid resuscitation, transfusion with blood products as indicated, followed by a laparotomy with Meckel's diverticulectomy and ileal resection

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  Explanation

  Hemorrhage associated with a Meckel's diverticulum classically presents with painless rectal bleeding in the absence of other gastrointestinal symptoms. The amount of hemorrhage may be enough to result in hypovolemia, with pallor, tachycardia, and postural hypotension. Abdominal examination is usually normal. Diagnosis is confirmed by technetium scan, with the isotope concentrated in the gastric mucosa of the diverticulum. Initial management should include IV fluid resuscitation and transfusion as needed, before laparotomy and diverticulectomy with resection of the adjacent ileum. Rectal polyps, hemorrhoids, and anal fissures may be associated with rectal bleeding. The bleeding is usually small in amount and often temporally related to defecation, typically on the surface of the stool or after defecation. Colonoscopy and proctoscopy are useful adjuncts to diagnosis. Bleeding associated with intussusception is described as "currant jelly" and is secondary to mucosal ischemia of the lead point. These children are most commonly between 2 months and 2 years of age, and often have a prodromal viral illness. They present with colicky abdominal pain and dehydration. Management includes hydrostatic reduction.

• Question 619:

  During diagnostic evaluation, a 14-year-old girl with menorrhagia, frequent nosebleeds, and irondeficiency anemia is found to have a low platelet count with a normal coagulation profile. Bone marrow biopsy reveals abundant megakaryocytes. On abdominal examination, no organomegaly is noted. The patient has a satisfactory response to the initial therapeutic intervention, but over 612 months' time, the response is less dramatic and shorter in duration. There are signs and symptoms of increasing side effects from therapy. The next step in management should be to recommend which of the following?

  A. partial splenectomy
  B. splenectomy
  C. increase in steroid dose and frequency
  D. bone marrow transplant
  E. plasmapheresis
  B. splenectomy

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  Explanation

  This patient has idiopathic thrombocytopenic purpura (ITP), a disease characterized by a low platelet count, normal coagulation profile, increased megakaryocytes, and a normal-sized spleen. Patients with ITP will often demonstrate excessive bleeding in response to a minor injury. Circulating antiplatelet antibodies coat normal platelets, which are then sequestered by the spleen, with resultant platelet destruction. The majority of patients respond to initial therapy with systemic steroids. Splenectomy is indicated in patients who become steroid dependent with significant side effects or in patients requiring increasing doses of steroids to maintain a satisfactory platelet count. The entire spleen must be excised, including any accessory spleens found at surgery. Residual splenic parenchyma would result in persistent platelet sequestration. Splenectomy is not indicated in the initial management of ITP. Platelet transfusion is rarely required. Spontaneous bleeding is unusual unless the platelet counts drop below 20,000/L. When this occurs, if the patient is not responsive to steroids, platelet transfusion and urgent splenectomy is indicated. Antineoplastic chemotherapy is not used in the management of ITP. Expectant management is associated with significant risk, as the most life- threatening complication of ITP is spontaneous intracerebral hemorrhage. Bone marrow transplant is not indicated. ITP is a disease of peripheral platelet destruction, with normal or increased platelet production.

• Question 620:

  A 39-year-old pregnant woman with chronic hypertension and one prior pregnancy is now at 38 weeks' gestation. She comes to labor and delivery with profuse vaginal bleeding and abdominal pain of sudden onset.

  This patient has an external fetal monitor placed. Uterine tone seems to be increased, and there are occasional variable decelerations of the fetal heart to 90 BPM. Which of the following is the most appropriate management?

  A. tocolysis with a -receptor agonist
  B. Pitocin induction of labor
  C. continued monitoring of mother and baby
  D. amniotomy
  E. cesarean section
  E. cesarean section

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  Explanation

  At term, a placental abruption severe enough to cause fetal distress warrants immediate delivery. If the pregnancy is remote from term, temporizing measures may be considered, such as observation. However, delivery should be achieved if the mother becomes hemodynamically unstable. Tocolysis is ineffective in relaxing the uterus and has the added disadvantage of causing vasodilation of an already under-filled vascular system. Amniotomy and Pitocin induction will not cause delivery rapidly enough to prevent further deterioration of the fetus. Evidence of fetal distress makes continued monitoring unacceptable.