A 79-year-old man residing in a skilled nursing facility is brought to the emergency depar… — USMLE Step 3

A 79-year-old man residing in a skilled nursing facility is brought to the emergency department due to progressively worsening abdominal distension, severe pain, and failure to pass stool or flatus over the past 48 hours. His medical history includes Parkinson disease, chronic constipation, and mild cognitive impairment. His temperature is $38.6^\circ\text{C}$ , blood pressure is $86/54\text{ mm Hg}$ , heart rate is $126\text{/min}$ , and respiratory rate is $24\text{/min}$ . He appears distressed and diaphoretic. Abdominal examination reveals profound distension with diffuse rigidity, marked tenderness to palpation, and rebound tenderness. Bowel sounds are absent. An upright plain radiograph of the abdomen displays a massive, dilated, inverted U-shaped loop of large bowel extending from the pelvis toward the right upper quadrant, with no free air under the diaphragm. Laboratory studies demonstrate a leukocyte count of $18,500/\mu\text{L}$ and serum lactate of $5.1\text{ mmol/L}$ . Following initial intravenous fluid resuscitation and broad-spectrum antibiotic administration, which of the following is the most appropriate next step in management?

Exploratory laparotomy with bowel resectionAnswer
B
Endoscopic detorsion via flexible sigmoidoscopy
C
Computed tomography of the abdomen and pelvis with intravenous contrast
D
Fluoroscopic water-soluble contrast enema
E
Admission to the intensive care unit for vasopressor support and serial abdominal examinations

Answer

Exploratory laparotomy with bowel resection

This patient has a sigmoid volvulus that has progressed to bowel ischemia and peritonitis. This is evidenced by his systemic inflammatory response (fever, leukocytosis), hemodynamic instability (hypotension, tachycardia), tissue hypoperfusion (elevated lactate), and peritonitis (rigidity, rebound tenderness). While uncomplicated sigmoid volvulus is typically managed with therapeutic flexible sigmoidoscopy to untwist the bowel, the presence of peritonitis or gangrene is an absolute indication for emergent exploratory laparotomy. Attempting endoscopic detorsion in an ischemic colon risks gross perforation.

Step-by-Step Solution

Analyze the patient's risk factors and radiographic findings.

The patient is an elderly male with Parkinson disease and chronic constipation presenting with a classic 'inverted U-shaped' (coffee bean) loop of bowel on radiograph, diagnosing a sigmoid volvulus.

Identifying the primary pathology is required before determining the appropriate intervention.

Evaluate the patient's clinical stability and physical examination findings.

The patient has fever, hypotension, tachycardia, leukocytosis, elevated lactate, and diffuse abdominal rigidity with rebound tenderness.

These findings indicate that the volvulus has progressed to strangulation, bowel ischemia, and peritonitis.

Select the appropriate procedural intervention based on the clinical status.

Because signs of bowel necrosis and peritonitis are present, non-operative measures are contraindicated. Emergent exploratory laparotomy with bowel resection is required.

First-line endoscopic management is reserved solely for patients without signs of ischemia or peritonitis.

Key Concept

Patients with sigmoid volvulus who exhibit signs of peritonitis, bowel ischemia, or perforation require immediate surgical exploration and resection rather than endoscopic detorsion.

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