What is the recommended evaluation and management for an adult presenting with acute severe abdominal pain, distension, bilious vomiting, obstipation and peritoneal signs suggestive of a closed‑loop intestinal obstruction?

Closed-Loop Intestinal Obstruction: Evaluation and Management

Immediate Recognition and Action

A patient presenting with acute severe abdominal pain, distension, bilious vomiting, obstipation, and peritoneal signs requires emergency surgical consultation immediately—this is a surgical emergency with mortality rates up to 25% if strangulation occurs, and every hour of delay worsens outcomes. 1, 2

Critical Initial Assessment

Physical Examination Red Flags

• Peritoneal signs (guarding, rebound tenderness, rigidity) indicate bowel ischemia or perforation and mandate immediate surgery 1, 2
• Fever, tachycardia, tachypnea, or confusion suggest strangulation/ischemia 1
• Intense pain unresponsive to analgesics is a warning sign of ischemia 1
• Absent bowel sounds (not hyperactive) indicate progression to ischemia 1
• Hemodynamic instability signals impending cardiovascular collapse from endotoxin release 2

Laboratory Evaluation

• Elevated lactate levels strongly suggest intestinal ischemia 1, 2
• Leukocytosis with neutrophilia indicates complications 1
• Metabolic acidosis (low bicarbonate, low arterial pH) suggests ischemia 1
• Renal function tests assess dehydration severity 1

Diagnostic Imaging

CT Abdomen/Pelvis with IV Contrast (First-Line)

CT with IV contrast is the diagnostic standard with >90% accuracy and must be obtained urgently 3, 1

• No oral contrast is needed in suspected high-grade obstruction 3, 1
• CT identifies closed-loop obstruction by showing:
  • C-shaped or U-shaped incarcerated bowel loop 4, 5
  • Radial distribution of dilated loops converging toward obstruction point 6, 5
  • Two transition points obstructing the same bowel segment 6, 4
  • Whirl sign at the site of obstruction 5

CT Signs of Ischemia Requiring Immediate Surgery

• Abnormal bowel wall enhancement (decreased or absent) 3, 1
• Mesenteric edema and ascites 3, 5
• Pneumatosis intestinalis 3
• Intraperitoneal fluid 3
• Bowel wall thickening with vascular congestion 5

Critical Pitfall: CT sensitivity for ischemia is only 15-52% prospectively, but when signs are present, they are highly specific 3. Clinical signs of peritonitis mandate surgery even with negative CT findings 2.

Management Algorithm

Patients WITH Peritoneal Signs or Ischemia Indicators

Proceed directly to emergency laparotomy—do not delay for additional imaging or conservative management 3, 2

Concurrent resuscitation while preparing for surgery:

• Aggressive IV fluid resuscitation 2
• Broad-spectrum antibiotics 2
• Nasogastric tube decompression 2
• Vasopressor support if hemodynamically unstable 2
• Foley catheter for monitoring 2

Surgical Treatment

• Immediate exploration to identify obstruction cause 2
• Revascularization if possible 2
• Assessment of bowel viability 2
• Resection of nonviable intestine 2
• Scheduled "second look" operation 24-48 hours later 2

Patients WITHOUT Peritoneal Signs (Rare in True Closed-Loop)

Even without overt peritonitis, closed-loop obstruction requires urgent surgical intervention due to high risk of rapid progression to strangulation 4, 7

• Older patients have increased risk of irreversible ischemia (OR 1.03 per year) 7
• ASA classification ≥3 increases risk of irreversible ischemia 3.76-fold 7
• Do not attempt conservative management with closed-loop obstruction—this is fundamentally different from simple bowel obstruction 4, 8

Key Distinctions from Simple Bowel Obstruction

Closed-loop obstruction is a distinct surgical emergency that cannot be managed conservatively 4:

• Simple obstruction has one transition point; closed-loop has two 6, 4
• Simple obstruction may respond to conservative management; closed-loop requires immediate surgery 4, 8
• Closed-loop has inherently compromised blood supply due to mesenteric twist or compression 4, 5
• Progression to strangulation occurs rapidly without intervention 6, 5

Common Pitfalls to Avoid

• Never attempt conservative management when closed-loop obstruction is identified on CT 4, 8
• Do not delay surgery waiting for laboratory confirmation of ischemia—clinical peritoneal signs are sufficient 2
• Do not order enteroclysis or small bowel follow-through in acute presentations—patients cannot tolerate these studies and they delay definitive treatment 3
• Recognize that absence of CT signs of ischemia does not exclude it—sensitivity is poor 3
• In elderly or high ASA patients, maintain even higher suspicion for irreversible ischemia 7

Outcomes

• Mortality with perforation: 27-70% 9, 2
• Mortality with strangulation if delayed: up to 25% 1
• Postoperative morbidity with irreversible ischemia: 45% vs 20% with reversible ischemia 7
• Hospital stay significantly longer with irreversible ischemia (median 8 days vs 5-6 days) 7