What is the appropriate management for a patient 5 days after a traumatic fall with multiple left‑side fractures on opioid analgesics, presenting with 6‑day constipation, a distended firm abdomen, and mildly decreased left lower lung sounds?

Management of Severe Opioid-Induced Constipation with Abdominal Distention in a Post-Trauma Patient

This patient requires immediate assessment for bowel obstruction or fecal impaction via physical examination and abdominal imaging, followed by aggressive escalation beyond her current regimen: increase bisacodyl to 10-15 mg two to three times daily, add polyethylene glycol 17g twice daily, and strongly consider methylnaltrexone 0.15 mg/kg subcutaneously every other day given her laxative-refractory opioid-induced constipation. 1, 2

Immediate Assessment (Rule Out Surgical Emergency)

Before escalating any laxative therapy, you must exclude bowel obstruction or complete fecal impaction, as the distended, firm abdomen raises serious concern for mechanical obstruction—escalating stimulant laxatives or adding peripherally acting μ-opioid receptor antagonists (PAMORAs) in the presence of obstruction risks perforation. 1, 2, 3

• Perform a thorough abdominal examination and digital rectal examination to assess for impaction. 2, 3
• Obtain an abdominal X-ray (or CT if clinical suspicion is high) to rule out mechanical obstruction, ileus, or severe impaction. 3
• The slightly diminished left lower lung sounds may reflect atelectasis from splinting due to pain and immobility, but also raises concern for aspiration risk if she develops nausea/vomiting from obstruction. 1

Aggressive Laxative Escalation (Second-Line Therapy)

Miralax (polyethylene glycol) and senna alone have clearly failed after 6 days. The 2023 WSES trauma guidelines and NCCN palliative care guidelines both emphasize that opioid-induced constipation in trauma patients is near-universal (80-95% incidence) and requires aggressive, stepwise escalation. 1, 2

Increase Stimulant Laxative Dose

• Escalate bisacodyl to 10-15 mg orally two to three times daily (30-45 mg total daily dose) to maximize colonic stimulation. 1, 2
• Alternatively, increase senna to higher doses if bisacodyl is not tolerated. 2

Add High-Dose Osmotic Laxative

• Add polyethylene glycol (PEG) 17g in 8 oz water twice daily (not just once daily as she may currently be taking) for its excellent safety profile and osmotic effect. 1, 2, 3
• If PEG is insufficient, consider adding lactulose 30-60 mL daily or magnesium hydroxide 30-60 mL daily—but use magnesium cautiously and check renal function first, as hypermagnesemia is a risk in patients with impaired kidney function. 1, 2, 3

Rectal Interventions (If Impaction Confirmed)

• If digital rectal exam reveals hard stool in the rectal vault, administer a glycerin or bisacodyl suppository to facilitate disimpaction. 1, 2, 3
• Manual disimpaction may be necessary after premedication with an analgesic ± anxiolytic. 3
• Avoid enemas if she has thrombocytopenia, neutropenia, or recent pelvic/abdominal trauma, as these are contraindications. 3

Third-Line Therapy: Peripherally Acting μ-Opioid Receptor Antagonist (PAMORA)

Given 6 days of constipation despite Miralax and senna, this patient meets criteria for laxative-refractory opioid-induced constipation. The 2019 AGA guidelines and NCCN guidelines both recommend PAMORAs for patients who fail adequate trials of stimulant and osmotic laxatives. 1, 2

• Methylnaltrexone 0.15 mg/kg subcutaneously every other day (maximum once daily) is the most practical PAMORA in the acute hospital setting, as it does not require oral administration and works within hours. 1, 2
• Methylnaltrexone blocks peripheral opioid receptors in the gut without crossing the blood-brain barrier, so it relieves constipation without reversing analgesia or causing opioid withdrawal. 1, 4, 5
• Naldemedine 0.2 mg orally once daily has the strongest evidence (high-quality) but requires oral administration, which may be challenging if she develops nausea or has gastroparesis. 2
• Naloxegol 12.5-25 mg orally once daily is another oral option with moderate-quality evidence. 2

Important PAMORA Precautions

• PAMORAs are absolutely contraindicated if bowel obstruction is present, as they can precipitate perforation. 2
• Monitor for signs of opioid withdrawal (sweating, chills, diarrhea, abdominal cramping, anxiety), though this is rare with peripherally restricted agents. 2

Optimize Pain Management to Reduce Opioid Burden

The 2023 WSES trauma guidelines emphasize that opioid-sparing multimodal analgesia is critical in elderly trauma patients to reduce constipation and other opioid-related complications. 1

• Consider regional anesthesia or nerve blocks (e.g., transversus abdominis plane block, quadratus lumborum block) if she has abdominal or rib fractures, as these provide superior analgesia compared to systemic opioids and improve bowel recovery. 1
• Add scheduled acetaminophen 1g IV every 6 hours (unless contraindicated) to reduce opioid requirements. 1
• Avoid NSAIDs in this elderly trauma patient due to risks of acute kidney injury, gastrointestinal bleeding, and drug interactions with antiplatelet agents or ACE inhibitors. 1
• Intravenous lidocaine infusion (1-2 mg/kg bolus, then 0.5-3 mg/kg/hr) can reduce opioid requirements and improve gastrointestinal motility, though evidence is mixed. 1
• Ketamine (low-dose infusion) is efficacious for reducing opioid needs but carries risk of psychiatric side effects in the elderly. 1

Supportive Measures

• Maximize hydration (oral or IV) to support laxative efficacy, as dehydration worsens constipation. 1, 2, 3
• Early mobilization is critical—even bed-to-chair transfers improve gut motility and reduce complications. 1, 3
• Avoid supplemental fiber (e.g., psyllium, Metamucil), as it is ineffective for opioid-induced constipation and may worsen obstruction in immobile patients. 1, 2, 3

Monitor for Complications

• The distended, firm abdomen and 6-day constipation raise concern for impending bowel obstruction, perforation, or stercoral ulceration—all of which carry high morbidity and mortality in elderly trauma patients. 1
• The diminished left lower lung sounds may reflect atelectasis from splinting due to left-sided rib fractures, but also consider aspiration pneumonia if she develops vomiting from obstruction. 1
• Serial abdominal exams and close monitoring of vital signs, abdominal girth, and bowel sounds are essential. 1

Common Pitfalls to Avoid

• Do not delay escalation of laxatives or addition of a PAMORA—6 days without a bowel movement in an opioid-treated trauma patient is a medical urgency. 1, 2
• Do not add more stool softeners (e.g., docusate)—they are ineffective for opioid-induced constipation and provide no benefit beyond stimulant laxatives. 1, 2
• Do not rely on dietary measures alone (fiber, prune juice)—these are insufficient for opioid-induced constipation. 1, 2
• Always exclude obstruction before escalating stimulant laxatives or adding PAMORAs, as this can precipitate perforation. 1, 2, 3
• Do not use magnesium-based laxatives if renal function is impaired, due to risk of life-threatening hypermagnesemia. 2, 3