A 29-year-old man with a history of ileocolonic Crohn's disease presents to the emergency … — USMLE Step 2 CK

A $29$ -year-old man with a history of ileocolonic Crohn's disease presents to the emergency department with a $24$ -hour history of severe, cramping abdominal pain and bilious vomiting. He reports not passing any flatus or stool since the pain began. Over the past $3$ hours, his pain has transitioned from colicky to constant and agonizing. His temperature is $38.7^\circ\text{C}$ ( $101.7^\circ\text{F}$ ), blood pressure is $92/58 \text{ mm Hg}$ , and heart rate is $118/\text{min}$ . Physical examination reveals a distended abdomen that is exquisitely tender to palpation in all four quadrants, with marked rigidity and rebound tenderness. Laboratory studies show a leukocyte count of $18,500/\text{mm}^3$ and a serum lactate of $3.9 \text{ mmol/L}$ . An abdominal radiograph demonstrates multiple dilated loops of small bowel with air-fluid levels and an absence of colonic gas. Which of the following is the most appropriate next step in management?

Immediate exploratory laparotomyAnswer
B
Placement of a nasogastric tube and serial abdominal examinations
C
Computed tomography scan of the abdomen and pelvis with intravenous contrast
D
Intravenous administration of corticosteroids and biologic therapy
E
Administration of broad-spectrum intravenous antibiotics and close observation

Answer

Immediate exploratory laparotomy

This patient presents with a small bowel obstruction (SBO) complicated by bowel strangulation and peritonitis, as evidenced by fever, hemodynamic instability, a rigid abdomen with rebound tenderness, marked leukocytosis, and elevated serum lactate. In a patient with Crohn's disease, chronic inflammation can lead to fibrotic strictures that cause mechanical obstruction. When an SBO is accompanied by signs of ischemia or peritonitis, it becomes a surgical emergency requiring immediate exploratory laparotomy to resect nonviable bowel and prevent catastrophic sepsis.

Step-by-Step Solution

Identify the primary clinical syndrome from the patient's presentation and imaging.

The patient has bilious vomiting, obstipation, and a radiograph showing dilated small bowel loops with air-fluid levels, consistent with a small bowel obstruction (SBO).

Establishing the baseline diagnosis is necessary to apply the correct management algorithm.

Evaluate for signs of complications, specifically bowel ischemia or strangulation.

The patient exhibits continuous severe pain, fever, tachycardia, hypotension, peritonitis (rigidity, rebound tenderness), leukocytosis, and elevated serum lactate.

Differentiating between an uncomplicated and complicated SBO dictates whether medical or surgical management is indicated.

Select the appropriate intervention based on the presence of complications.

Because signs of bowel strangulation and peritonitis are clearly present, the patient requires emergent surgical exploration.

Delaying surgery for imaging or attempting conservative medical management in the setting of an ischemic, strangulated bowel will lead to necrosis, perforation, and overwhelming sepsis.

Key Concept

Management of complicated small bowel obstruction (SBO) with signs of strangulation

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