A 72-year-old woman is brought to the emergency department by her family due to a 3-day hi… — USMLE Step 3

A $72$ -year-old woman is brought to the emergency department by her family due to a $3$ -day history of worsening abdominal distension, severe crampy abdominal pain, and an inability to pass flatus or stool. Her past medical history is significant for hypertension and osteoarthritis. Her temperature is $37.4^{\circ}\text{C}$ ( $99.3^{\circ}\text{F}$ ), blood pressure is $135/85\text{ mmHg}$ , pulse is $98/\text{min}$ , and respiratory rate is $16/\text{min}$ . Physical examination reveals a markedly distended, tympanic abdomen with diffuse mild tenderness but no rebound or guarding. Computed tomography (CT) of the abdomen and pelvis with intravenous contrast reveals an obstructing mass in the sigmoid colon with severe proximal large bowel dilation. The cecum measures $11.5\text{ cm}$ in diameter. There is no free intraperitoneal air. Intravenous fluids and nasogastric decompression are initiated. Which of the following are appropriate next steps in the procedural management of this patient? (Select all that apply)

Endoscopic placement of a self-expanding metal stentAnswer
Emergent laparotomy with bowel resection and proximal diversionAnswer
C
Administration of an oral polyethylene glycol-based bowel preparation
D
Barium enema for further delineation of the obstruction
E
Continued nonoperative observation with serial abdominal plain films over the next $48$ hours

Answer

The correct appropriate next steps are endoscopic placement of a self-expanding metal stent and emergent laparotomy with bowel resection and proximal diversion.

The correct procedural interventions are endoscopic placement of a self-expanding metal stent and emergent laparotomy with bowel resection. This patient presents with a malignant left-sided large bowel obstruction and a cecal diameter of

11.5\text{ cm}

. According to Laplace's law, the cecum experiences the greatest wall tension and is at the highest risk of perforation when distended. A diameter exceeding

10\text{ cm}

indicates impending rupture and requires urgent procedural decompression. This can be achieved through immediate surgical intervention (such as a Hartmann procedure) or through the placement of an endoscopic self-expanding metal stent (SEMS), which decompresses the colon and serves as a 'bridge' to an elective, safer, single-stage surgical resection.

Step-by-Step Solution

Analyze the clinical presentation and diagnostic findings.

The patient has a symptomatic large bowel obstruction caused by a sigmoid mass, with a cecal diameter of

11.5\text{ cm}

Identifying the severity of the obstruction is required to dictate the urgency of procedural intervention.

Evaluate the risk of complications based on imaging.

A cecum measuring greater than

10\text{ cm}

indicates impending perforation, often due to a closed-loop obstruction involving a competent ileocecal valve.

Impending perforation necessitates immediate procedural decompression rather than observation or medical management alone.

Select the appropriate procedural interventions for acute decompression.

Both endoscopic stenting (as a bridge to surgery) and emergent surgical resection (with diversion) are valid, definitive means to urgently decompress the colon and prevent perforation.

These interventions directly resolve the mechanical obstruction safely, whereas oral preparations and barium are contraindicated.

Key Concept

Management of acute large bowel obstruction with impending cecal perforation requires urgent procedural decompression via either endoscopic stenting or emergent surgical resection.

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