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Difficulty: MediumInterpreting Imaging Results

A 72-year-old man is evaluated in the emergency department for severe, diffuse abdominal pain that began suddenly 3 hours ago. His medical history is significant for hypertension, type 2 diabetes mellitus, and paroxysmal atrial fibrillation, for which he has been noncompliant with his anticoagulant medication. Temperature is 37.8°C (100.0°F), blood pressure is 105/65 mmHg, pulse is 118/min and irregular, and respiratory rate is 22/min. Physical examination reveals a mildly distended abdomen with diffuse tenderness but no focal guarding or rebound tenderness. Bowel sounds are hypoactive. Laboratory studies show a leukocyte count of 18,500/mm³ and a serum lactate level of 5.2 mmol/L. A contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis reveals diminished enhancement of the small bowel wall, linear gas collections within the intestinal wall, and branching radiolucencies extending to the peripheral subcapsular regions of the liver. Based on the patient's presentation and imaging findings, which of the following is the most appropriate next step in management?

  1. Emergent exploratory laparotomyAnswer
  2. B
    Conventional mesenteric angiography
  3. C
    Endoscopic retrograde cholangiopancreatography
  4. D
    Intravenous broad-spectrum antibiotics and serial abdominal examinations
  5. E
    Upright plain abdominal radiography

Answer

Emergent exploratory laparotomy
The correct management is emergent exploratory laparotomy. The patient presents with classic features of acute mesenteric ischemia (pain out of proportion to exam, atrial fibrillation, elevated lactate) that has progressed to transmural bowel infarction. The CT imaging findings are pathognomonic for necrotic bowel: pneumatosis intestinalis (linear gas collections within the bowel wall) and portal venous gas (branching radiolucencies extending to the periphery of the liver). Once transmural necrosis has occurred, immediate surgical exploration and resection of the necrotic bowel is the only definitive, life-saving treatment.

Step-by-Step Solution

1
Analyze the clinical presentation.
The patient has severe abdominal pain out of proportion to the physical exam, elevated lactate, and a history of uncoagulated atrial fibrillation, strongly suggesting acute mesenteric ischemia.
Identifying the underlying clinical syndrome provides context for interpreting the imaging findings.
2
Interpret the specific CT imaging findings.
Linear gas in the intestinal wall represents pneumatosis intestinalis, and peripheral branching gas in the liver represents portal venous gas.
These findings represent advanced gas-forming bacterial translocation due to transmural bowel necrosis.
3
Determine the appropriate management based on the imaging interpretation.
Immediate surgical resection via exploratory laparotomy is required.
Transmural bowel infarction is a surgical emergency; delaying surgery for further diagnostics or attempting non-operative management results in overwhelming sepsis and death.

Key Concept

Interpreting CT signs of transmural bowel infarction (pneumatosis intestinalis and portal venous gas) to guide emergent surgical intervention.
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Interpreting Imaging Results

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