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Key Features


Essentials of Diagnosis


  • • Precipitating factors

    • – Surgery

      – Peritonitis

      – Electrolyte abnormalities

      – Severe medical illness

    • Nausea, vomiting, obstipation, distention

    • Minimal abdominal tenderness; decreased bowel sounds

    • Plain abdominal radiography with gas and fluid distention in small and large bowel


General Considerations


  • • Neurogenic failure or loss of peristalsis in the intestine in the absence of any mechanical obstruction

    • Common in hospitalized patients as a result of the following

    • – Intra-abdominal processes, such as

      • ▪ Recent gastrointestinal or abdominal surgery

        ▪ Peritoneal irritation (peritonitis, pancreatitis, ruptured viscus, hemorrhage)

      – Severe medical illness, such as

      • ▪ Pneumonia

        ▪ Respiratory failure requiring intubation

        ▪ Sepsis or severe infections

        ▪ Uremia

        ▪ Diabetic ketoacidosis

        ▪ Electrolyte abnormalities (hypokalemia, hypercalcemia, hypomagnesemia, hypophosphatemia)

      – Medications, such as

      • ▪ Opioids

        ▪ Anticholinergics

        ▪ Phenothiazines

    • Postoperative ileus is reduced by

    • – Use of patient-controlled or epidural analgesia

      – Avoidance of intravenous opioids

      – Early ambulation

      – Gum chewing

      – Initiation of a clear liquid diet


Clinical Findings


Symptoms and Signs


  • • Mild diffuse, continuous abdominal discomfort

    • Nausea and vomiting

    • Generalized abdominal distention

    • Minimal abdominal tenderness

    • No signs of peritoneal irritation

    • Bowel sounds are diminished to absent


Differential Diagnosis


  • • Mechanical obstruction of small intestine or proximal colon, eg, adhesions, volvulus, Crohn disease

    • Chronic intestinal pseudo-obstruction




Laboratory Tests


  • • Obtain serum electrolytes, potassium, magnesium, phosphorus, and calcium


Imaging Studies


  • • Plain abdominal radiography: air-fluid levels, distended gas-filled loops of small and large intestine

    • Limited barium small bowel series or a CT scan can help exclude mechanical obstruction






  • • Alvimopan

    • – A peripherally acting mu-opioid receptor antagonist with limited absorption or systemic activity that reverses opioid-induced inhibition of intestinal motility

      – Reduces time to first flatus, bowel movement, solid meal, and hospital discharge in postoperative patients

      – May be considered in patients undergoing partial large or small bowel resection when postoperative opioid therapy is anticipated


Therapeutic Procedures


  • • Treat underlying primary medical or surgical illness

    • Nasogastric suction for discomfort or vomiting

    • Restrict oral intake, administer intravenous fluids

    • Liberalize diet gradually as bowel function returns

    • Minimize anticholinergic and opioid medications

    • Severe or prolonged ileus requires nasogastric suction and infusion of parenteral fluids and electrolytes






  • • Return of bowel function usually heralded by return of appetite and passage of flatus

    • Serial plain film radiography and/or abdominal CT warranted for persistent or worsening symptoms to distinguish from mechanical obstruction




  • • Ileus usually resolves within 48–72 h


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