What is the management for ileus (intestinal obstruction) identified on a computed tomography (CT) scan?

Management of Ileus Identified on CT Scan

Begin with conservative management including bowel rest, nasogastric decompression (if symptomatic with nausea/vomiting), intravenous fluid resuscitation with electrolyte correction, and serial clinical examinations to monitor for complications or progression to mechanical obstruction. 1, 2

Initial Assessment and Differentiation

Once ileus is identified on CT, the critical first step is distinguishing true ileus (adynamic/paralytic) from mechanical obstruction, as management differs significantly:

Key CT Features Distinguishing Ileus from Mechanical Obstruction

• Ileus characteristics: Diffuse bowel dilatation without a clear transition point, gas distributed throughout small and large bowel 3, 4
• Mechanical obstruction indicators: Clear transition point from dilated to decompressed bowel, "beak sign," "small bowel feces sign," mesenteric edema, bowel wall thickening, and fat stranding 1, 4
• CT with IV contrast has >90% accuracy in making this distinction and should be the primary imaging modality 1, 5, 3

Conservative Management Protocol

Bowel Rest and Decompression

• Keep patient NPO (nothing by mouth) initially 2
• Insert nasogastric tube only if patient has prominent nausea or vomiting—routine prophylactic NG tube placement is not recommended 2
• Avoid oral intake until bowel function returns 2

Fluid and Electrolyte Management

• Administer isotonic crystalloid fluids within a restrictive regimen (avoid fluid overload which can worsen bowel edema) 2
• Regularly evaluate and correct electrolyte abnormalities, particularly potassium, magnesium, and calcium, as these directly affect bowel motility 2
• Replace ongoing losses (NG output, vomiting) with balanced isotonic crystalloid containing supplemental potassium 2

Medication Review and Adjustment

• Immediately review and minimize opioid analgesics, as these are major contributors to ileus 2
• Substitute with regular acetaminophen, NSAIDs (if not contraindicated), and tramadol as needed 2
• Discontinue or minimize anticholinergic medications, which impair gut motility 6

Mobilization

• Encourage regular ambulation as soon as medically feasible, as this promotes bowel function recovery 2

Monitoring for Complications

Serial Clinical Examination

• Perform serial abdominal examinations to detect development of peritoneal signs (rebound tenderness, guarding) which indicate perforation or ischemia requiring urgent surgery 7, 1
• Monitor for progression of symptoms despite conservative management 1

Warning Signs Requiring Urgent Surgical Consultation

• CT signs of bowel ischemia: Abnormal bowel wall enhancement, intramural hyperdensity, pneumatosis intestinalis, portal venous gas 1, 4
• Development of peritoneal signs on physical examination 1
• Severe, constant abdominal pain unresponsive to analgesia 1
• Signs of sepsis or hemodynamic instability (tachycardia, hypotension, fever) 7, 6
• Failure of conservative management after 3-5 days 2

Nutritional Support

• If patient cannot tolerate adequate oral intake for more than 7 days postoperatively (in postoperative ileus), initiate parenteral nutrition 2
• In non-postoperative ileus, consider enteral feeding trial once bowel sounds return and patient passes flatus 2
• Failure to tolerate enteral feeding should raise concern for underlying mechanical obstruction or bowel injury 7

Special Considerations

Intra-abdominal Hypertension

• Ileus can lead to bowel dilatation and increased intra-abdominal pressure (IAP), found in up to 20% of critically ill patients 6
• Monitor for abdominal compartment syndrome (IAP >20-25 mmHg with organ dysfunction), which requires urgent decompression 6
• Severe cases may require colonic tube placement or decompressive laparotomy 6

Water-Soluble Contrast Challenge

• Consider administering water-soluble contrast (50-150 mL orally or via NG tube) if diagnosis remains uncertain between partial obstruction and ileus 7, 5
• If contrast reaches colon within 24 hours, this predicts successful non-operative management 5
• Caution: Ensure adequate gastric decompression first to avoid aspiration; may cause dehydration in elderly or children due to high osmolarity 7

When to Abandon Conservative Management

Proceed to surgery if:

• Peritoneal signs develop 1
• CT demonstrates ischemia, perforation, or closed-loop obstruction 1, 4
• Clinical deterioration despite 48-72 hours of appropriate conservative therapy 2
• Development of abdominal compartment syndrome 6

Common Pitfalls to Avoid

• Do not administer prokinetic agents (metoclopramide) if complete obstruction cannot be excluded, as this may cause perforation 7
• Avoid administering oral contrast in high-grade obstruction due to aspiration risk 1
• Do not delay surgical consultation in patients with concerning CT findings (ischemia, closed-loop) even if clinically stable 4
• Do not overlook electrolyte abnormalities, particularly hypokalemia and hypomagnesemia, which perpetuate ileus 2