Certain medications can also impair the motility of the gastrointestinal tract by either inhibiting its muscular contractions or preventing its muscles from contracting in the organized fashion needed to cause peristalsis (the wave-like movements of the intestine that propel its contents forward). Included in this group of medications are those termed anticholinergics. Glycopyrrolate, trazodone, and risperidone are all anticholinergic medications.
Malnutrition can also predispose to the development of gastrointestinal dysmotility. In particular, low blood levels of potassium and magnesium can impair coordinated contractions of the bowel and thereby impair peristalsis.
Distention of the bowel also worsens bowel dysmotility, as stretching a muscle causes it to contract less effectively. Chronic constipation causes distention of the colon.
Ogilvie syndrome, i.e., acute colonic pseudo-obstruction, is acute dilation of part or all of the colon in the absence of a mechanical obstruction. In other words, the dilation occurs secondary to profound dysmotility of the colon rather than physical blockage of the colon. Anticholinergic medications can cause Ogilvie syndrome. People who have underlying bowel dysmotility due to cerebral palsy are at increased risk of developing colonic pseudo-obstruction.
The colonic distention that occurs secondary to Ogilvie syndrome starts in the first part of the colon (cecum) and progressively extends to the rectum. The rectum is the last part of the bowel to become distended in Ogilvie syndrome. In severe cases, the rectum can distend to the point that it prolapses through the anus. Complications of Ogilvie syndrome, including bowel perforation, respiratory compromise, and death, are most likely to occur if the condition is not appropriately treated within six days. Multiple treatments can reverse the condition, including: decompression of the bowel through nasogastric, gastric, or rectal tubes; discontinuation of medications contributing to the bowel dysmotility; administration of a medication called neostigmine; exsufflation of the colon via colonoscopy; and, surgical interventions.