USMLE Step 2 Quiz
Practice Surgical Emergencies in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 67-year-old man presents with a 3-day history of worsening left lower quadrant pain, fever, and nausea. A CT scan of the abdomen reveals acute diverticulitis with a 5 cm pericolic abscess.
What is the most appropriate initial management?
This quiz focuses on Surgical Emergencies, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 67-year-old man presents with a 3-day history of worsening left lower quadrant pain, fever, and nausea. A CT scan of the abdomen reveals acute diverticulitis with a 5 cm pericolic abscess.
What is the most appropriate initial management?
Explanation: This patient has complicated diverticulitis with a well-defined abscess > 4 cm. The standard of care for a stable patient with a contained abscess of this size is CT-guided percutaneous drainage for source control, combined with intravenous antibiotics. This approach often allows the acute inflammation to resolve, avoiding an emergent, high-risk surgery and potentially allowing for an elective, single-stage resection later. Surgery (sigmoidectomy) is reserved for patients with diffuse peritonitis, those who fail non-operative management, or for elective management of recurrent disease. Antibiotics alone are insufficient for an abscess of this size.
A patient is in the operating room for suspected appendicitis. Upon entering the abdomen, the surgeon finds a perforated appendix with a 4-cm well-contained abscess in the right lower quadrant. The surrounding bowel appears healthy.
What is the most appropriate intraoperative management?
Explanation: When complicated appendicitis (perforation with abscess) is encountered during surgery, the standard of care is to perform an appendectomy to remove the source of infection and to drain the abscess cavity. Leaving the appendix in situ (draining only) leads to a high rate of recurrence and the need for a second surgery. A right hemicolectomy is reserved for cases where the cecum is necrotic or if there is concern for a cecal malignancy. Closing the abdomen without source control would be inadequate and dangerous.
A 62-year-old man with a history of severe peripheral vascular disease is hospitalized for sepsis from a urinary tract infection. He is treated with vasopressors for hypotension. On day 3 of his admission, he develops diffuse abdominal pain and passes a large amount of bloody diarrhea. A CT scan of the abdomen is performed.
Which of the following CT findings would be most concerning for transmural bowel necrosis requiring surgical intervention?
Explanation: This patient has developed non-occlusive mesenteric ischemia (NOMI) due to a low-flow state (sepsis, vasopressor use) in the setting of underlying vascular disease. While bowel wall thickening and fat stranding are signs of inflammation or ischemia, pneumatosis intestinalis (air in the bowel wall) is a highly specific sign of severe ischemia and impending or frank transmural necrosis. The presence of pneumatosis intestinalis, especially with associated portal venous gas, is often an indication for emergent surgical exploration and resection of non-viable bowel.
A 30-year-old woman who is 28 weeks pregnant presents with 12 hours of right-sided abdominal pain, nausea, and low-grade fever. On examination, she has tenderness in the right upper quadrant, superior and lateral to McBurney's point. Her white blood cell count is 16,000/mm³, which can be a normal finding in pregnancy. The clinical suspicion for appendicitis is high, but the presentation is atypical due to uterine displacement of the appendix.
Which of the following is the most appropriate imaging modality to confirm the diagnosis?
Explanation: In a pregnant patient with suspected appendicitis, imaging is often necessary due to the atypical presentation and physiologic leukocytosis. Graded-compression ultrasonography is the initial imaging modality of choice because it is effective and avoids ionizing radiation to the fetus. If the ultrasound is non-diagnostic, MRI is the preferred next step. CT scan is generally avoided due to radiation exposure unless the diagnosis remains uncertain and the risk of a missed diagnosis is high. Diagnostic laparoscopy is an invasive surgical procedure used for treatment once the diagnosis is strongly suspected or confirmed.
A 50-year-old man presents with an acute onset of tearing chest pain that radiates to his back between the scapulae. His blood pressure is 190/110 mm Hg in the right arm and 150/90 mm Hg in the left arm. A chest radiograph shows a widened mediastinum. The patient suddenly develops severe, acute abdominal pain with diffuse tenderness.
The development of acute abdominal pain in this patient is most likely due to which of the following?
Explanation: This patient's presentation is classic for an acute aortic dissection. The sudden development of severe abdominal pain suggests that the dissection flap has extended to involve the abdominal aorta and is now compromising blood flow to one of the major visceral arteries, such as the superior mesenteric artery, leading to acute mesenteric ischemia. This is a catastrophic complication of aortic dissection. A ruptured AAA would present with abdominal/back pain and shock, but the preceding tearing chest pain and blood pressure differential point to dissection. Pancreatitis is less likely. Referred pain would not typically be this severe or cause peritoneal signs.
A 78-year-old man with a history of atrial fibrillation, not on anticoagulation, is brought to the emergency department with 4 hours of sudden, severe, diffuse abdominal pain. His temperature is 37.2°C (99.0°F), blood pressure is 130/80 mm Hg, and heart rate is 110/min and irregular. The physical examination is notable for a soft, non-distended abdomen with only mild, diffuse tenderness. His lactate level is 4.5 mmol/L (normal 0.5-1 mmol/L).
Which of the following is the most likely diagnosis?
Explanation: This patient's presentation is classic for acute mesenteric ischemia (AMI), specifically due to an arterial embolism from his untreated atrial fibrillation. The hallmark of AMI is severe abdominal pain that is 'out of proportion' to the physical exam findings. The elevated lactate level is a key finding indicating tissue hypoxia and impending bowel necrosis. Acute pancreatitis typically has epigastric pain radiating to the back and elevated lipase. A perforated ulcer would cause peritonitis with a rigid abdomen. Diverticulitis usually presents with left lower quadrant pain and tenderness.
A 22-year-old man presents with a 24-hour history of abdominal pain that began in the periumbilical region and has now localized to the right lower quadrant. He has associated nausea and has not eaten since yesterday. His temperature is 38.1°C (100.6°F), and his white blood cell count is 14,500/mm³ with a left shift. On examination, there is maximal tenderness at McBurney's point with guarding. His Alvarado score is 8.
What is the most appropriate next step in management?
Explanation: This patient has a classic presentation of acute appendicitis, including migratory pain, fever, leukocytosis, and localized right lower quadrant tenderness. In a young male with a classic presentation and a high Alvarado score (≥7), the diagnosis is considered highly likely, and further imaging is often unnecessary and can delay definitive treatment. The most appropriate next step is an urgent surgical consultation for appendectomy. While imaging (CT or ultrasound) is often used in equivocal cases or in populations where the diagnosis is less certain (e.g., women of childbearing age, the elderly), it is not required here. Antibiotics and observation would be inappropriate as this is a surgical disease requiring definitive source control.
An 82-year-old woman with a history of a prior hysterectomy presents with two days of crampy abdominal pain, nausea, and vomiting. She has not passed stool or flatus for 24 hours. Her abdomen is distended and tympanitic. An upright abdominal radiograph reveals multiple dilated loops of small bowel with air-fluid levels and a paucity of gas in the colon.
What is the most likely cause of this patient's condition?
Explanation: The clinical presentation and radiographic findings are classic for a small bowel obstruction (SBO). In a patient with a history of prior abdominal surgery, intra-abdominal adhesions are the most common cause of SBO. An incarcerated hernia is a possible cause, but it would typically be evident on physical exam. Colon cancer and sigmoid volvulus are causes of large bowel obstruction, which would present with a dilated colon on imaging, not primarily dilated small bowel loops.
A 45-year-old woman presents with right upper quadrant pain, fever, and jaundice. Her temperature is 39.2°C (102.6°F), heart rate is 115/min, and blood pressure is 95/65 mm Hg. Laboratory studies show a white blood cell count of 18,000/mm³, total bilirubin of 4.5 mg/dL, and elevated alkaline phosphatase. An abdominal ultrasound demonstrates a dilated common bile duct with a stone visible in the distal portion.
In addition to intravenous fluids and antibiotics, which of the following is the most appropriate next step in management?
Explanation: This patient presents with Charcot's triad (fever, RUQ pain, jaundice) and hypotension, which constitutes Reynolds' pentad, indicating severe acute cholangitis. This is a surgical emergency caused by biliary obstruction and subsequent infection. The most critical intervention is to decompress the biliary tree. Urgent Endoscopic Retrograde Cholangiopancreatography (ERCP) with sphincterotomy and stone extraction is the procedure of choice to relieve the obstruction. While cholecystectomy will be needed later, biliary drainage is the immediate priority. Percutaneous drainage is a second-line option if ERCP is not available or fails. MRCP is a diagnostic, not therapeutic, tool.
A 65-year-old woman with a history of peripheral artery disease and hypertension presents with 24 hours of crampy left lower quadrant pain and the passage of a small amount of bright red blood per rectum. She had an episode of hypotension yesterday during a medical procedure. On examination, she has mild to moderate tenderness in the left lower quadrant without rebound or guarding. A CT scan of the abdomen shows thickening of the colonic wall at the splenic flexure.
What is the most likely diagnosis?
Explanation: This patient's presentation is classic for ischemic colitis. It typically occurs in the setting of a low-flow state (hypotension) in patients with underlying atherosclerosis. The pain is usually less severe than in acute mesenteric ischemia, and it is often accompanied by bloody diarrhea. The splenic flexure is a common location as it is a 'watershed' area between the superior and inferior mesenteric artery circulations. Diverticulitis typically does not cause significant bleeding. Acute mesenteric ischemia causes much more severe pain. Infectious colitis is possible but less likely given the clear precipitating event of hypotension.
A 40-year-old intravenous drug user presents with a 3-day history of rapidly worsening pain, swelling, and redness over his left forearm. He admits to injecting heroin into the area 4 days ago. His temperature is 39.5°C (103.1°F), and he appears toxic. Examination of the forearm reveals tense edema, erythema with indistinct borders, and extreme pain on passive extension of his fingers. Several large, purplish bullae are present.
Which of the following physical exam findings is most specific for necrotizing fasciitis in this patient?
Explanation: While all the listed findings are concerning, severe pain out of proportion to the visible signs of cellulitis is a classic and early hallmark of necrotizing fasciitis. This is thought to be due to ischemia and infarction of the nerves in the affected fascial planes. Bullae, tense edema, and erythema can be seen in severe cellulitis or abscess, but the excruciating pain, especially with passive muscle movement, is highly suggestive of a deep, necrotizing process that requires immediate surgical exploration.
An 80-year-old resident of a nursing home presents with acute onset of abdominal distension and pain. He has not had a bowel movement in 3 days. He has a history of chronic constipation and dementia. An abdominal radiograph shows a massively dilated loop of colon in the shape of an inverted 'U', with the apex in the right upper quadrant.
Which of the following is the most appropriate initial step in management?
Explanation: The clinical history and the classic 'coffee bean' or inverted 'U' sign on abdominal radiograph are diagnostic of a sigmoid volvulus. In the absence of peritoneal signs or evidence of ischemia, the initial management is non-operative decompression. Flexible sigmoidoscopy can be both diagnostic and therapeutic, allowing for untwisting of the volvulus and placement of a rectal tube to maintain decompression. Emergent laparotomy is indicated if there are signs of perforation or ischemia, or if sigmoidoscopic decompression fails. A barium enema can be diagnostic ('bird's beak' sign) but is less preferred for initial therapy. NG tube and fluids are supportive but not definitive.
A surgeon is performing a debridement for necrotizing fasciitis of the lower leg. During the procedure, the subcutaneous tissue is gray and necrotic, and there is a copious amount of thin, brownish, foul-smelling exudate ('dishwater fluid'). Probing the fascial planes with a finger meets with little resistance.
This infection is most commonly caused by which type of organism?
Explanation: There are two main types of necrotizing fasciitis. Type I, which is more common overall, is a polymicrobial infection involving a mix of aerobic and anaerobic bacteria (e.g., streptococci, enterococci, Enterobacteriaceae, Bacteroides, Clostridium). It often occurs in patients with underlying comorbidities like diabetes. The finding of foul-smelling 'dishwater fluid' and gas (crepitus) is characteristic of a polymicrobial infection with anaerobes. Type II is a monomicrobial infection, most classically caused by Group A Streptococcus (the 'flesh-eating bacteria'), and is less common.
A 10-year-old boy is evaluated for 18 hours of right lower quadrant pain, anorexia, and fever. An ultrasound is performed, but the appendix cannot be visualized due to overlying bowel gas. The clinical suspicion for appendicitis remains high.
What is the most appropriate next step in management?
Explanation: In pediatric patients with suspected appendicitis and an equivocal ultrasound, a period of active clinical observation with serial examinations is an accepted approach. This allows the clinical picture to evolve, either progressing to clear appendicitis (necessitating surgery) or resolving (suggesting an alternative diagnosis like mesenteric adenitis). While MRI is increasingly used in pediatric patients to avoid radiation exposure, it may not be immediately available and serial clinical assessment remains a standard approach. Proceeding directly to surgery carries the risk of negative appendectomy, and antibiotics alone are inappropriate without confirmed diagnosis.
A 45-year-old woman with a history of Crohn disease, previously managed with infliximab, presents with progressive abdominal distension, crampy pain, and vomiting for 3 days. An abdominal CT scan confirms a high-grade small bowel obstruction at the terminal ileum due to a fibrotic stricture.
What is the most appropriate definitive management for this patient?
Explanation: This patient has a small bowel obstruction due to a fibrotic stricture from long-standing Crohn disease. While an inflammatory component may be present, a fixed, fibrotic stricture causing a high-grade obstruction will not respond to medical therapy like corticosteroids. TPN is supportive care, not definitive treatment. Endoscopic balloon dilation can be used for short, accessible strictures but is often not feasible for high-grade obstructions in the terminal ileum. Therefore, the definitive management is surgical, involving either resection of the affected segment (ileocecal resection) or a stricturoplasty to widen the lumen without resecting bowel.
A 75-year-old man undergoes a CT angiography of the abdomen for evaluation of claudication. The scan reveals an incidental 6.0 cm fusiform infrarenal abdominal aortic aneurysm. The patient is asymptomatic. On follow-up, he presents to the emergency department with the sudden onset of severe abdominal and back pain and is found to be hypotensive with a pulsatile abdominal mass.
What is the most appropriate immediate action?
Explanation: The clinical triad of abdominal/back pain, hypotension, and a pulsatile abdominal mass in a patient with a known large AAA is diagnostic of a ruptured abdominal aortic aneurysm (rAAA). This is a dire surgical emergency with extremely high mortality. The immediate priority is surgical consultation for emergent repair (either open or endovascular). Any delay for further imaging (ultrasound or CT) in a hemodynamically unstable patient is inappropriate and increases the risk of death. Administering antihypertensives is contraindicated in a hypotensive patient; permissive hypotension is often targeted until hemorrhage is controlled.
A 60-year-old woman with a history of recurrent urinary tract infections develops left flank pain, fever, and chills. A CT scan of her abdomen reveals a large obstructing stone in the left proximal ureter with associated hydronephrosis and perinephric stranding. She is septic, with a blood pressure of 85/50 mmHg despite fluid resuscitation.
What is the most urgent intervention required for this patient?
Explanation: This patient has an obstructive pyelonephritis leading to septic shock, which is a urologic emergency. While antibiotics (which should be started immediately) and vasopressors are critical supportive measures, the definitive management requires source control. The infected and obstructed urinary system must be urgently decompressed to allow drainage of purulent material and resolution of the infection. This can be achieved either by placing a retrograde ureteral stent via cystoscopy or by percutaneous nephrostomy tube placement. ESWL is contraindicated in the setting of active infection and obstruction.
A 34-year-old man is brought to the emergency department after a bar fight. He sustained a stab wound to the left upper quadrant of his abdomen. He is awake and alert, but his blood pressure is 90/60 mm Hg and heart rate is 130/min. His abdomen is tender and becoming distended.
What is the most appropriate next step in management?
Explanation: This patient has a penetrating abdominal injury and is hemodynamically unstable. The presence of hypotension, tachycardia, and signs of peritonitis (tenderness, distension) after penetrating trauma is a clear indication for immediate exploratory laparotomy. There is no role for delaying definitive surgical intervention with further diagnostic studies like FAST or CT scan in an unstable patient. Local wound exploration is inadequate to rule out intra-abdominal injury.
A 28-year-old woman presents with one week of bloody diarrhea, crampy abdominal pain, and fever. On examination, she has diffuse abdominal tenderness. A plain abdominal radiograph shows a colon dilated to 8 cm in the transverse section, with loss of haustral markings.
This patient is at immediate risk for which of the following life-threatening complications?
Explanation: The clinical presentation and radiographic findings are diagnostic of toxic megacolon, a severe complication of inflammatory bowel disease (most commonly ulcerative colitis) or infectious colitis (like C. difficile). It is characterized by acute colonic dilation (transverse colon > 6 cm) with systemic toxicity. The thinning and inflammation of the colonic wall place the patient at high and immediate risk of perforation, which can lead to fulminant peritonitis and death. While fistula, cancer, and strictures are long-term complications of IBD, perforation is the acute, life-threatening risk in toxic megacolon that mandates urgent medical and potential surgical intervention.
A 70-year-old man presents with vomiting and abdominal distension. An abdominal radiograph shows dilated loops of small bowel. A CT scan is performed which shows a transition point in the right groin, where a loop of bowel is seen entering the inguinal canal. The patient has a non-reducible, tender mass in the right groin on examination.
What is the diagnosis?
Explanation: The patient has signs and symptoms of a small bowel obstruction. The key finding on both physical exam (non-reducible, tender groin mass) and CT scan (transition point in the inguinal canal) is an incarcerated inguinal hernia. This is a common cause of SBO, especially in elderly men who may not have noticed the hernia previously. This is a surgical emergency because incarceration can lead to strangulation and bowel necrosis.