Neurogenic bowel dysfunction

Neurogenic bowel dysfunction
Other names	Neurogenic bowel
The image shows the 4 parts of the colon (ascending, transverse, descending and sigmoid) and the rectum. Feces are transported along and stored in the rectum before excretion.
Specialty	Gastroenterology

Neurogenic bowel dysfunction (NBD) is reduced ability or inability to control defecation due to deterioration of or injury to the nervous system, resulting in fecal incontinence or constipation.^[1] It is common in people with spinal cord injury (SCI), multiple sclerosis (MS) or spina bifida.^[2]

The gastrointestinal tract (GI tract) has a complex control mechanism that relies on coordinated interaction between muscular contractions and neuronal impulses (nerve signals).^[3] Fecal incontinence or constipation occurs when there is a problem with normal bowel functioning. This could be for a variety of reasons. The normal defecation pathway involves contractions of the colon which helps mix the contents, absorb water and propel the contents along. This results in feces moving along the colon to the rectum.^[4] The presence of stool in the rectum causes reflexive relaxation of the internal anal sphincter (rectoanal inhibitory reflex), so the contents of the rectum can move into the anal canal. This causes the conscious feeling of the need to defecate. At a suitable time the brain can send signals causing the external anal sphincter and puborectalis muscle to relax as these are under voluntary control and this allows defecation to take place.^[4][5]

Spinal cord injury and other neurological problems mostly affect the lower GI tract (i.e., jejunum, ileum, and colon) leading to symptoms of incontinence or constipation. However, the upper GI tract (i.e., esophagus, stomach, and duodenum) may also be affected and patients with NBD often present with multiple symptoms.^[6][7] Research shows there is a high prevalence of upper abdominal complaints, for example a study showed that approximately 22% of SCI patients reported feeling bloated,^[6][8] and about 31% experienced abdominal distension.^[6][9]