What is the initial treatment approach for a patient presenting with ileus (a condition of inhibited movement of the bowel), considering potential causes such as medication-induced ileus, postoperative ileus, or other underlying conditions?

Treatment for Ileus

The initial treatment for ileus is strictly nothing by mouth (NPO), aggressive intravenous isotonic fluid resuscitation with correction of electrolyte abnormalities (especially potassium and magnesium), immediate discontinuation of all opioids and antimotility agents, and early mobilization once stable. 1

Immediate Initial Management

Bowel Rest and Decompression

• Keep the patient strictly NPO until ileus resolves, as oral feeding worsens abdominal distension and is contraindicated 1
• Place a nasogastric tube for decompression only if there is severe abdominal distention, vomiting, or aspiration risk—not routinely 2, 1
• Remove the nasogastric tube as early as possible, as prolonged decompression paradoxically extends ileus duration rather than shortening it 2

Fluid Resuscitation

• Administer isotonic crystalloid solutions (lactated Ringer's or normal saline) intravenously to correct dehydration 1
• In severe dehydration or shock, give initial fluid boluses of 20 mL/kg 1
• Critical pitfall to avoid: Do not overload fluids—aim for weight gain limited to <3 kg by postoperative day three, as fluid overload causes intestinal edema and significantly prolongs ileus 2
• Avoid 0.9% saline due to risk of salt and fluid overload 2
• Target adequate central venous pressure and urine output >0.5 mL/kg/hour 1

Electrolyte Correction

• Aggressively correct hypokalemia, hypomagnesemia, and hyponatremia, as these directly impair intestinal motility 2, 1
• Correct hypomagnesemia first with intravenous magnesium sulfate, then transition to oral magnesium oxide 2
• Address sodium depletion before correcting potassium, as hypokalemia is typically secondary to hyperaldosteronism from sodium depletion 2
• Monitor serum creatinine, potassium, and magnesium every 1-2 days initially 2

Medication Management

• Immediately discontinue all opioids, antimotility agents (especially loperamide), anticholinergics, antidiarrheals, antispasmodics, phenothiazines, and haloperidol 1, 3
• This is non-negotiable—these medications directly worsen ileus and must be stopped completely 1

Pain Management Strategy

Opioid-Sparing Analgesia

• Implement mid-thoracic epidural analgesia with local anesthetic as the cornerstone of pain management, as this is highly effective at preventing and treating ileus 2
• Use multimodal analgesia: regular paracetamol (acetaminophen), regular NSAIDs (unless contraindicated), and tramadol as needed 2
• Consider abdominal wall blocks (such as TAP blocks) as adjuncts to reduce opioid consumption 2

Early Mobilization

• Begin mobilization immediately once the patient's condition allows—this is crucial for stimulating bowel function 2, 1
• Early removal of urinary catheters facilitates mobilization 2
• Encourage regular ambulation as tolerated, as this decreases pulmonary complications, thromboembolism, and insulin resistance 1

Pharmacological Interventions (Once Oral Intake Resumes)

Laxatives and Prokinetics

• Once oral intake is tolerated, administer bisacodyl 10-15 mg orally 2-3 times daily and oral magnesium oxide 3, 2
• Consider metoclopramide 10-20 mg orally four times daily as a prokinetic agent for persistent ileus or gastroparesis, though evidence for effectiveness is limited 2, 4
• Chewing gum starting as soon as the patient is awake stimulates bowel function through cephalic-vagal stimulation 2

Special Consideration for Opioid-Induced Ileus

• If ileus is opioid-related and conservative measures fail, consider methylnaltrexone 0.15 mg/kg subcutaneously every other day (maximum once daily) 3, 2
• Critical contraindication: Do not use methylnaltrexone in postoperative ileus or mechanical bowel obstruction 3
• Alternative agents include naloxegol, lubiprostone, or linaclotide for refractory opioid-induced cases 2

Rescue Therapy for Persistent Ileus

• For ileus persisting beyond 5 days despite optimal conservative management, consider water-soluble contrast agents or neostigmine as rescue therapy 2, 5
• Investigate for mechanical obstruction, intra-abdominal sepsis, or other complications if ileus persists beyond 7 days 2

Nutritional Support

Timing of Feeding

• Resume early oral intake with small portions once bowel sounds return, particularly after right-sided resections and small-bowel anastomoses 2
• Do not delay oral intake based solely on absence of bowel sounds—early feeding maintains intestinal function even in the presence of ileus 2
• If oral intake will be inadequate (<50% of caloric requirement) for more than 7 days, initiate tube feeding within 24 hours 2
• If enteral feeding is contraindicated (intestinal obstruction, sepsis, intestinal ischemia, high-output fistulae, severe GI hemorrhage), provide early parenteral nutrition 2, 1

Monitoring

• Monitor vital signs frequently (at least four times daily) 1
• Reassess hydration status after 2-4 hours initially 1
• Evaluate for signs of return of intestinal function (passage of flatus or stool) 1
• Monitor abdominal distension and bowel sounds 1
• Obtain daily abdominal radiography if colonic dilatation is detected at presentation 1

Thromboprophylaxis

• Administer subcutaneous heparin to reduce risk of thromboembolism, as immobilized patients with ileus are at high risk 1

Critical Pitfalls to Avoid

• Do not routinely place nasogastric tubes—they prolong rather than shorten ileus duration 2
• Do not continue opioids—these are a primary modifiable cause of prolonged ileus 2
• Do not overload fluids—this is one of the most common and preventable causes of prolonged ileus 2
• Do not delay mobilization or oral intake based solely on absence of bowel sounds 2
• In children, never use antimotility drugs like loperamide, as this can lead to severe complications 6