Definition

• Acute intestinal pseudo-obstruction or ileus consists of impaired transit of intestinal contents and obstructive symptoms (nausea, vomiting, abdominal distension, lack of bowel movements) without a mechanical explanation.
• Acute colonic pseudo-obstruction or Ogilvie syndrome describes massive colonic dilation without mechanical obstruction in the presence of a competent ileocecal valve, resulting from impaired colonic peristalsis.
• Chronic intestinal pseudo-obstruction is characterized by recurrent episodes of nausea, vomiting, and abdominal distention with bowel dilation without mechanical obstruction.¹ An exact cause is often not found. One well-described etiology is a paraneoplastic phenomenon from antineuronal antibodies (anti-Hu), most often seen with small cell lung cancer.

Etiology

Ileus is frequently seen in the postoperative period. Narcotic analgesics administered for postoperative pain control may contribute, as can other medications that slow down intestinal peristalsis (calcium channel blockers, anticholinergic medications, TCAs, antihistamines). Other predisposing causes include virtually any medical insult, particularly life-threatening systemic diseases, infection, vascular insufficiency, and electrolyte abnormalities. Similar factors predispose to acute colonic pseudo-obstruction.