What is the initial management for a patient with small bowel ileus?

Initial Management of Small Bowel Ileus

The initial management of small bowel ileus should focus on bowel rest (NPO status), intravenous fluid resuscitation, correction of electrolyte abnormalities, and nasogastric tube insertion for decompression. 1

Diagnostic Evaluation

Before initiating treatment, it's crucial to differentiate between functional ileus and mechanical small bowel obstruction:

• Clinical assessment: Look for abdominal distension (most reliable physical finding), colicky abdominal pain, nausea, vomiting, and absence of stool/flatus 1
• Laboratory tests: CBC (WBC >10,000/mm³ suggests inflammation), electrolytes (particularly potassium), renal function, lactate levels (elevated in bowel ischemia) 1
• Imaging: CT abdomen and pelvis with IV contrast is the preferred initial imaging modality with >90% diagnostic accuracy 1, 2

Management Algorithm

Step 1: Supportive Care

• Bowel rest: NPO status to reduce intestinal workload
• Fluid resuscitation: IV fluids to correct dehydration and electrolyte imbalances
• Decompression: Nasogastric tube placement to relieve distension and vomiting 1
• Urinary catheter: To monitor urine output and fluid status

Step 2: Address Underlying Causes

• Exclude/treat other causes: Intra-abdominal sepsis, partial obstruction, enteritis, recurrent disease in the bowel, or abrupt stopping of drugs 3
• Medication review: Minimize medications that affect motility, especially opioids and anticholinergics 1

Step 3: Pharmacological Management

• Prokinetics: Consider metoclopramide for mild cases without mechanical obstruction 4
• Antimotility agents: For high-output states, loperamide 2-8 mg before food may be helpful 3
• Antibiotics: If bacterial overgrowth is suspected, consider rotating courses of antibiotics such as rifaximin (first choice), metronidazole, or ciprofloxacin 3
• Acid suppression: If net "secretory" output (>3 L/24 hours), consider H2 antagonists or proton pump inhibitors 3

Step 4: Nutritional Support

• Early nutritional assessment: Calculate BMI and percentage weight loss 1
• Enteral nutrition: Preferred if gut is accessible and functioning 3
• Parenteral nutrition: Consider if NPO status is prolonged (>5-7 days) or if enteral feeding is not tolerated 1

Special Considerations

For High-Output States

• Reduce oral hypotonic fluids to 500 ml/day 3
• Provide glucose-saline solution to sip (sodium concentration at least 90 mmol/l) 3
• Separate solids and liquids (no drink for half an hour before or after food) 3

For Persistent Ileus

• Early surgical consultation is recommended, particularly with signs of peritonitis, perforation, or bowel ischemia 1
• Consider octreotide for refractory cases with high secretory output (can reduce output by 1-2 L/24 hours) 3

Common Pitfalls and Caveats

1. Misdiagnosis: Failing to distinguish between functional ileus and mechanical obstruction can lead to inappropriate management. CT is superior to clinical and plain film evaluations for this distinction 2

2. Delayed surgical consultation: Early surgical consultation is essential even when planning conservative management 1

3. Electrolyte imbalances: Hypomagnesemia is common and often overlooked. It may cause dysfunction of potassium transport systems and increase renal potassium excretion 3

4. Medication effects: Abrupt stopping of steroids or opiates can worsen ileus, while prokinetics like metoclopramide may be harmful in mechanical obstruction 3

5. Inadequate fluid resuscitation: In severe cases, consider intravenous normal saline (2-4 L/day) while keeping the patient NPO to demonstrate that output is driven by oral intake 3

By following this systematic approach, most cases of small bowel ileus can be managed effectively, reducing morbidity and improving patient outcomes.