How should a 65‑year‑old man with a known psychiatric disorder on quetiapine who presents with recurrent severe periumbilical colicky pain and has a normal abdominal ultrasound (US) and non‑contrast computed tomography (CT) be evaluated and managed?

Evaluation and Management of Recurrent Severe Periumbilical Colicky Pain in a 65-Year-Old Male on Quetiapine

This patient requires immediate contrast-enhanced CT imaging during an episode of pain to exclude life-threatening quetiapine-induced intestinal ischemia or necrosis, followed by urgent surgical consultation if any concerning features are identified.

Critical Drug-Induced Etiology

Quetiapine carries a significant risk of anticholinergic-induced gastrointestinal complications, including intestinal ischemia and necrosis, which can be rapidly fatal. 1, 2 The French Pharmacovigilance database documented 38 cases of ischemic colitis and gastrointestinal necrosis associated with antipsychotics, with a mortality rate of 36.8% despite surgical intervention. 2 Quetiapine specifically has been implicated in fatal cases of intestinal necrosis, particularly when combined with other anticholinergic agents. 1, 3

Key Clinical Features of Antipsychotic-Induced Intestinal Complications:

• Recurrent colicky periumbilical pain is the hallmark presenting symptom and should never be dismissed as benign in patients on quetiapine 1, 4
• Initial imaging may be falsely reassuring because ischemia can be intermittent or early in its course 5, 6
• Rapid progression to necrosis, perforation, and septic shock can occur within hours to days despite initially mild symptoms 1, 2
• The average age of affected patients is 42.7 years, but elderly patients are at higher risk due to reduced physiologic reserve 2

Immediate Diagnostic Approach

Obtain Contrast-Enhanced CT During Pain Episode

The single most important diagnostic step is obtaining an abdominal CT scan with intravenous contrast during an episode of severe pain. 5, 6 Non-contrast CT has limited sensitivity (48-50%) for detecting early or low-grade obstruction and cannot adequately assess bowel wall perfusion. 6

Specific imaging findings that mandate emergent surgical consultation include: 5, 6

• Bowel wall thickening with abnormal enhancement pattern
• Mesenteric edema or fat stranding
• Pneumatosis intestinalis (gas within bowel wall)
• Portal venous gas
• Closed-loop configuration
• Transition point with proximal bowel dilation
• Free intraperitoneal air

Alternative Imaging if Contrast Contraindicated

If the patient has severe renal impairment or true contrast allergy:

• MR enterography provides detailed contrast-free evaluation and can detect subtle ischemic changes 6
• Point-of-care ultrasound offers 90% sensitivity for small bowel obstruction and can identify transition points, though it is operator-dependent 6

Exclude Mechanical Obstruction

Even with normal initial imaging, intermittent mechanical obstruction from adhesions must be excluded in this clinical scenario. 5, 6

Clinical Features Suggesting Mechanical Obstruction:

• Symptoms that reliably worsen after solid food intake 6
• Visible peristalsis on abdominal examination (in thin patients) 5, 6
• History of prior abdominal surgery (85% sensitivity for adhesive obstruction) 6
• Loud bowel sounds during pain episodes 5
• Relief with liquid or low-residue diet 5

A transition point between dilated and normal-caliber bowel on imaging confirms mechanical obstruction, but this may not be visible if the obstruction has resolved or if the bowel is fixed by adhesions. 5

Management Algorithm

If Imaging Reveals High-Risk Features:

1. Immediate surgical consultation 5, 6
2. Discontinue quetiapine and all anticholinergic medications immediately 1, 2
3. Nil-by-mouth status with intravenous crystalloid resuscitation 6
4. Nasogastric decompression if obstruction present 6
5. Broad-spectrum antibiotics if perforation or ischemia suspected 1, 2

If Initial Imaging is Normal but Symptoms Persist:

1. Discontinue quetiapine immediately given the life-threatening risk of progression 1, 2
2. Coordinate with psychiatry to transition to an antipsychotic with minimal anticholinergic effects (e.g., aripiprazole, ziprasidone, or first-generation agents like loxapine) 1
3. Obtain repeat contrast-enhanced CT during the next pain episode 5, 6
4. Consider water-soluble contrast study (using non-iodinated agents if contrast allergy) to differentiate complete from partial obstruction 6
5. Serial clinical monitoring for development of peritonitis, fever, or hemodynamic instability 1, 2

Critical Pitfalls to Avoid

Do not continue quetiapine while pursuing a diagnostic workup. The mortality rate from antipsychotic-induced intestinal necrosis is 36.8%, and progression can be rapid despite initially mild symptoms. 2 Six patients in the French database died despite surgical intervention, and 13 recovered with permanent sequelae. 2

Do not assume functional pain or irritable bowel syndrome in a patient on quetiapine with recurrent severe colicky pain. 5, 6 The anticholinergic effects of quetiapine decrease intestinal peristalsis, and without prompt recognition and management, this can progress to colonic ischemia or necrosis. 1, 2

Do not add opioid analgesics for pain control, as they will worsen intestinal dysmotility and can precipitate narcotic bowel syndrome, further complicating the clinical picture. 5

Do not rely on laboratory markers alone. Leukocytosis may be absent early in the course, and metabolic acidosis is a late finding indicating advanced ischemia. 1, 4

Examine all hernia orifices systematically, especially the femoral canal, as missed hernias can cause intermittent obstruction with high strangulation risk. 6

Monitoring After Quetiapine Discontinuation

If quetiapine is discontinued and symptoms resolve:

• Do not rechallenge with quetiapine or structurally similar antipsychotics (olanzapine, clozapine), as cross-reactivity for gastrointestinal complications has been documented 1, 7, 3
• Coordinate closely with psychiatry to select an alternative antipsychotic with minimal anticholinergic burden 1
• Counsel the patient and caregivers about the need for immediate medical evaluation if abdominal pain recurs 2