USMLE USMLE Certifications USMLE-STEP-2 Questions & Answers

• Question 171:

  A 55-year-old woman presents with a 6-month history of weight loss, abdominal cramps, and intermittent nonbloody diarrhea. On examination, her abdomen is mildly distended and there is a palpable mass in the right lower quadrant. Stool cultures yield normal fecal flora. CT scan with oral contrast demonstrates an inflammatory mass in the right lower quadrant, with thickening of the terminal ileum and ileocecal valve. Which of the following is the best diagnostic test to confirm the diagnosis?

  A. repeat CT scan with delayed imaging

  B. ultrasonography

  C. sigmoidoscopy

  D. colonoscopy

  E. small-bowel radiography

  Correct Answer: E

  Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that presents with intermittent crampy abdominal pain and diarrhea. It most commonly involves the terminal ileum and right colon. Because eating can exacerbate symptoms, oral intake may be decreased, contributing to the associated weight loss. Transmural inflammation leads to bowel wall thickening, and with adjacent mesenteric inflammation, the patient may develop a palpable mass. It may be difficult to differentiate Crohn's disease from ulcerative colitis on the basis of history and clinical examination.

  However, ulcerative colitis is a mucosal disease that is limited to the colon and nearly always involves the rectum. Diarrhea is usually bloody, and hemorrhage may be significant enough to require transfusion therapy. Complicated appendicitis may present with a right lower quadrant mass and diarrhea if there is perforation with abscess formation. The history is that of an acute illness in a previously well patient. Irritable bowel syndrome is associated with intermittent crampy abdominal pain, and diarrhea alternating with constipation. There is no inflammatory process, and weight loss is not a clinical feature. Evaluation of the small bowel is best accomplished with contrast radiography, such as a small-bowel follow-through study or enteroclysis. Radiographic abnormalities of small-bowel Crohn's disease are often distinctive and can demonstrate complications such as strictures and fistulae. CT scanning does not assist in confirming the diagnosis, but is helpful in detecting such complications as abscess. Ultrasonography has limited value. Sigmoidoscopy may not be useful, because Crohn's disease commonly spares the rectum and may be worse on the right side of the colon. Colonoscopy may be helpful when the colon is involved and when intubation of the ileocecal valve can be achieved; however, the disease may be limited to the small bowel resulting in a nondiagnostic examination.

  The principle of initial management of Crohn's disease is relief of symptoms, nutritional therapy, and suppression of the inflammatory process. Nutritional supplementation may require TPN in conjunction with bowel rest. Acute exacerbations of the disease are initially treated with systemic steroids. The use of antispasmodics may be effective in the treatment of irritable bowel syndrome. In Crohn's disease, however, antispasmodics may lead to an ileus or toxic bowel dilatation. Surgery in Crohn's disease is indicated for the management of complications, including fistula or abscess formation, stricture with obstruction, and perforation.

• Question 172:

  A 55-year-old woman presents with a 6-month history of weight loss, abdominal cramps, and intermittent nonbloody diarrhea. On examination, her abdomen is mildly distended and there is a palpable mass in the right lower quadrant. Stool cultures yield normal fecal flora. CT scan with oral contrast demonstrates an inflammatory mass in the right lower quadrant, with thickening of the terminal ileum and ileocecal valve. Which of the following is the most likely diagnosis?

  A. ulcerative colitis

  B. appendicitis

  C. Crohn's disease

  D. irritable bowel syndrome

  E. lactose intolerance

  Correct Answer: C

  Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that presents with intermittent crampy abdominal pain and diarrhea. It most commonly involves the terminal ileum and right colon. Because eating can exacerbate symptoms, oral intake may be decreased, contributing to the associated weight loss. Transmural inflammation leads to bowel wall thickening, and with adjacent mesenteric inflammation, the patient may develop a palpable mass. It may be difficult to differentiate Crohn's disease from ulcerative colitis on the basis of history and clinical examination.

  However, ulcerative colitis is a mucosal disease that is limited to the colon and nearly always involves the rectum. Diarrhea is usually bloody, and hemorrhage may be significant enough to require transfusion therapy. Complicated appendicitis may present with a right lower quadrant mass and diarrhea if there is perforation with abscess formation. The history is that of an acute illness in a previously well patient. Irritable bowel syndrome is associated with intermittent crampy abdominal pain, and diarrhea alternating with constipation. There is no inflammatory process, and weight loss is not a clinical feature. Evaluation of the small bowel is best accomplished with contrast radiography, such as a small-bowel follow-through study or enteroclysis. Radiographic abnormalities of small-bowel Crohn's disease are often distinctive and can demonstrate complications such as strictures and fistulae. CT scanning does not assist in confirming the diagnosis, but is helpful in detecting such complications as abscess. Ultrasonography has limited value. Sigmoidoscopy may not be useful, because Crohn's disease commonly spares the rectum and may be worse on the right side of the colon. Colonoscopy may be helpful when the colon is involved and when intubation of the ileocecal valve can be achieved; however, the disease may be limited to the small bowel resulting in a nondiagnostic examination.

  The principle of initial management of Crohn's disease is relief of symptoms, nutritional therapy, and suppression of the inflammatory process. Nutritional supplementation may require TPN in conjunction with bowel rest. Acute exacerbations of the disease are initially treated with systemic steroids. The use of antispasmodics may be effective in the treatment of irritable bowel syndrome. In Crohn's disease, however, antispasmodics may lead to an ileus or toxic bowel dilatation. Surgery in Crohn's disease is indicated for the management of complications, including fistula or abscess formation, stricture with obstruction, and perforation.

• Question 173:

  A29-year-old nonhelmeted motorcycle driver is involved in a single vehicular crash, resulting in a significant closed-head injury. He is intubated in the field and transported to a level 1 trauma center. On arrival, he is oxygenating well with assisted ventilation and has a normal blood pressure and moderate tachycardia. His Glasgow Coma Score is 7, and his pupils are equal and sluggishly reactive. After stabilization in the emergency department, the patient undergoes a CT scan of the head that demonstrates a small amount of subarachnoid blood and a right frontal lobe contusion with edema with no midline shift. CT scan of the abdomen is normal. The patient is transferred to the ICU. The optimal initial management of this patient's intracranial pressure (ICP) would be which of the following?

  A. craniotomy

  B. fluid restriction, hyperventilation, and osmotic diuresis

  C. fluid restriction, hyperventilation, and ventriculostomy

  D. hyperventilation and IV steroids

  E. normovolemia, normocarbia, sedation, and ventriculostomy

  Correct Answer: E

  The guiding principle of management of closed-head injury is to maintain cerebral perfusion and oxygenation; thereby, preventing secondary brain insult. Cerebral perfusion pressure (CPP) is dependent on systemic blood pressure, circulating blood volume, and ICP (i.e., CPP = mean BP - ICP). Normal CPP requires an adequate circulating blood volume with maintenance of normovolemia. Hypercarbia should be avoided because it leads to cerebral vasodilatation and increased ICP. Early insertion of a ventriculostomy is beneficial to permit controlled drainage of CSF as required to maintain a normal ICP. Fluid restriction and hyperventilations hould be avoided in the early stages of management of a closed-head injury. Autoregulation of cerebral blood flow is disrupted in the early phases after head injury. Aggressive hyperventilation with resultant cerebral vasoconstriction may precariously compromise the perfusion to the injured brain and to the surrounding noninjured brain. In patients with deteriorating neurologic status and/ or evidence of increasing ICP that is not well controlled with a ventriculostomy, osmotic diuretics and moderate hyperventilation may be useful adjuncts to therapy. The use of steroids in the management of closed-head injury is not indicated. Craniotomy is indicated for increased ICP attributed to a mass with a midline shift.

• Question 174:

  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

  Correct Answer: B

  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 175:

  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.

  Which of the following is the most appropriate diagnostic study to order for this patient?

  A. colonoscopy

  B. barium enema

  C. technetium scan

  D. UGI contrast study with small-bowel follow-through

  E. laparoscopy

  Correct Answer: C

  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 176:

  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.

  Which of the following is the most likely diagnosis?

  A. a bleeding Meckel's diverticulum

  B. juvenile rectal polyp

  C. hemorrhoids

  D. an anal fissure

  E. intussusception

  Correct Answer: A

  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 177:

  A 26-year-old previously healthy man was pinned under a crane at a construction site. After a prolonged extrication, he was brought to the emergency department, immobilized on a back board and receiving 100% oxygen by mask. He is alert and complaining of chest pain with respiratory effort. On examination, he is found to have an oxygen saturation of 90% by pulse oximetry, shallow respirations at a respiratory rate of 35/min, heart rate of 120 beats/min, and a blood pressure of 85/60 mmHg. The trachea is deviated to the right. There is tenderness and crepitation over the left chest wall, asymmetric chest wall movement, and decreased air entry over the left lung field. Which of the following is the most appropriate next step in the initial evaluation and management of this patient?

  A. fluid resuscitation with 2 L of isotonic crystalloid

  B. needle decompression of the left chest, followed by insertion of a chest tube

  C. portable chest x-ray

  D. immediate intubation and assisted ventilation

  E. emergency department thoracotomy

  Correct Answer: B

  This patient has a left tension pneumothorax, a diagnosis established based on symptoms and clinical examination. The patient is hypoxic, with respiratory distress, and demonstrates deviation of the mediastinum to the contralateral side. Hypotension is from the mediastinal shift that compromises venous return and not from hypovolemia. Therefore, aggressive fluid resuscitation is not indicated. A chest x-ray is unnecessary and will delay definitive life-saving intervention. The patient requires urgent decompression with a largebore needle in the second intercostal space anteriorly, followed by insertion of a chest tube. Although assisted ventilation can improve oxygenation, positive pressure may increase the pneumothorax if initiated before adequate decompression.

• Question 178:

  A25-year-old woman was involved in a motor vehicle crash and sustained a significant closed-head injury,

  a pulmonary contusion, and a pelvic fracture. She is unresponsive and is ventilated in the intensive care

  unit (ICU).

  Which of the following is the best initial approach to the management of this patient's nutritional needs?

  A. insertion of a subclavian venous catheter and initiation of central IV hyperalimentation

  B. wait for extubation and improvement of neurologic status, allowing institution of an oral caloric intake

  C. early institution of NG or nasojejunal tube feeding with an elemental formulation

  D. wait for resolution of the associated gastrointestinal ileus, followed by delayed initiation of NG tube feeding with a complex hypercaloric formulation

  E. peripheral IV hyperalimentation

  Correct Answer: C

  During the early catabolic phase after injury, nutritional support is essential in the management of the multiply injured patient. Elemental tube feeding can be initiated via the NG route, or via the nasojejunal route if there is delayed gastric emptying. Enteral nutrition will aid in maintaining the integrity of the gastrointestinal mucosal barrier; thereby, reducing the risk of bacterial translocation and sepsis. The enteral route is less expensive than parenteral nutrition and does not subject the patient to the complications associated with an indwelling central venous catheter

• Question 179:

  A40-year-old previously healthy man presents with sudden onset of severe abdominal pain that radiates from the right loin (flank) to groin. This pain is associated with nausea, sweating, and urinary urgency. He is distressed and restless, but an abdominal examination is normal. Which of the following is the most appropriate next step in management?

  A. insertion of a urethral catheter

  B. IV fluid hydration, IV analgesics, and nonenhanced computed tomography(CT) scan

  C. IV fluid hydration, IV analgesics, and arrangements for lithotripsy

  D. cystoscopy and retrograde pyelogram

  E. urine culture, followed by initiation of antibiotic therapy

  Correct Answer: B

  The clinical signs and symptoms of a ureteral calculus are secondary to sudden obstruction of a hollow viscus, with visceral referred pain from loin to groin. The pain is severe and colicky in nature, with ureteral peristalsis against the obstruction. This is often associated with reflex vomiting mediated by visceral stretch and pain fibers. Typically, the patient is restless and cannot find a position of comfort. Urinary urgency and hematuria are common. Torsion of the testes produces sudden scrotal pain, and may have associated vague lower abdominal pain and vomiting. Pyelonephritis is associated with flank pain and costovertebral angle tenderness that is progressive in severity and constant in nature.

  Appendicitis will present with vague periumbilical pain, migrating to the right lower quadrant with the development of peritonitis. In the latter stages, the patient will lie quietly, as movement exacerbates the pain from peritoneal irritation. By increasing hydration and adequate analgesia, most patients will pass ureteral stones spontaneously. An imaging study should be obtained in all patients presenting with symptoms of urinary calculi. Nonenhanced CT scan will identify the location of the stone, size, and number of stones. This information assists with planning further management options, including referral for lithotripsy or cystoscopy and retrograde ureteroscopy.

• Question 180:

  A40-year-old previously healthy man presents with sudden onset of severe abdominal pain that radiates

  from the right loin (flank) to groin. This pain is associated with nausea, sweating, and urinary urgency. He

  is distressed and restless, but an abdominal examination is normal.

  Which of the following is the most likely diagnosis?

  A. torsion of the right testicle

  B. pyelonephritis

  C. appendicitis

  D. right ureteral calculus

  E. acute urinary retention

  Correct Answer: D

  The clinical signs and symptoms of a ureteral calculus are secondary to sudden obstruction of a hollow viscus, with visceral referred pain from loin to groin. The pain is severe and colicky in nature, with ureteral peristalsis against the obstruction. This is often associated with reflex vomiting mediated by visceral stretch and pain fibers. Typically, the patient is restless and cannot find a position of comfort. Urinary urgency and hematuria are common. Torsion of the testes produces sudden scrotal pain, and may have associated vague lower abdominal pain and vomiting. Pyelonephritis is associated with flank pain and costovertebral angle tenderness that is progressive in severity and constant in nature.

  Appendicitis will present with vague periumbilical pain, migrating to the right lower quadrant with the development of peritonitis. In the latter stages, the patient will lie quietly, as movement exacerbates the pain from peritoneal irritation. By increasing hydration and adequate analgesia, most patients will pass ureteral stones spontaneously. An imaging study should be obtained in all patients presenting with symptoms of urinary calculi. Nonenhanced CT scan will identify the location of the stone, size, and number of stones. This information assists with planning further management options, including referral for lithotripsy or cystoscopy and retrograde ureteroscopy.