Intestinal obstruction (non-mechanical)

Non-mechanical intestinal obstruction (often called intestinal pseudo-obstruction) is characterized by the dilation of bowel in the absence of an anatomical obstruction.

Patients present with the signs and symptoms of bowel obstruction, including nausea, vomiting, abdominal distension, and constipation with bowel dilation on x-ray or CT imaging.

Although the exact cause of acute intestinal pseudo-obstruction is unknown, current theories suggest that the inhibition of parasympathetic activity, dysregulation of stretch receptors, and decreased ganglion cells in the colonic smooth muscle play an important role. Other possible factors include reduced splanchnic perfusion, anticholinergic medications, opiates, hypokalaemia, and uraemia (1)

It occurs most commonly in men and patients over the ages of 60. The annual incidence is estimated to be around 100/100,000 for every inpatient admission. (2)

Abdominal distension is the key clinical feature in intestinal pseudo-obstruction, occurring in about 80% of cases. (1)

Treatment involves decompression of the dilated colon to prevent bowel ischemia and perforation (3)

Surgery remains the final option when other measures have failed or if the patient's condition continues to worsen. Options include placing a cecostomy tube or performing a colectomy. (4)

Large bowel pseudo-obstruction prognosis depends on the development of bowel ischemia or perforation, which occurs in 3% to 15% of cases. The mortality rate with ischemic bowel or perforation is 40% versus 15% without perforation. (5)

References

1. Wells CI, O'Grady G, Bissett IP. Acute colonic pseudo-obstruction: A systematic review of aetiology and mechanisms. World J Gastroenterol. 2017 Aug 14;23(30):5634-5644.
2. Ross SW et al. Acute Colonic Pseudo-obstruction: Defining the Epidemiology, Treatment, and Adverse Outcomes of Ogilvie's Syndrome. Am Surg. 2016 Feb;82(2):102-11.
3. Eisen GM et al. Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy. Acute colonic pseudo-obstruction. Gastrointest Endosc. 2002 Dec;56(6):789-92.
4. De Giorgio R, Knowles CH. Acute colonic pseudo-obstruction. Br J Surg. 2009 Mar;96(3):229-39.
5. Saunders MD, Kimmey MB. Systematic review: acute colonic pseudo-obstruction. Aliment Pharmacol Ther. 2005 Nov 15;22(10):917-25.