How paralysis impacts the digestive and bowel systems

The digestive tract in its entirety is a hollow tube beginning at the mouth and ending at the anus. The bowel, the final portion of the tract, is where the waste products of digested food are stored until they are emptied from the body in the form of stool, or feces.

Paralysis disrupts the bowel system and causes complications ranging from constipation to accidents. If you are living with or impacted by paralysis, it is important to understand the digestive tract and how to manage bowel complications to preserve health and quality of life.

The journey of digestion

From the first bite to a bowel movement, digestion requires a delicate coordination of several organs and autonomic functions.

After food is swallowed, it moves through the esophagus to the stomach, which is basically a storage bag, and then on to the intestines or bowels. The absorption of nutrients occurs in the small intestines, the duodenum, the jejunum and the ileum. Next is the colon, which encircles the abdomen, starting on the right with the ascending colon, passing across the top with the transverse colon, and down the “s”-shaped sigmoid colon to the rectum, which opens at the anus.

Feces move through the bowel by coordinated muscular contractions of the colon walls called peristalsis. This motion is managed by a network of nerve cells at several different levels. If the intestine wall is stretched, the myenteric plexus nerves direct local intestinal movement by triggering the muscles above the stretch to constrict and those below to relax, propelling material down the tube.

The next level of organization comes from autonomic nerves from the brain and spinal cord to the colon, which receives messages through the vagus nerve. The highest level of control comes from the brain to discriminate between feces and gas, and the decision to eliminate when appropriate.

Messages relayed via the spinal cord produce voluntary relaxation of the pelvic floor and anal sphincter muscles, allowing the defecation process to occur.

Effects of paralysis on the bowel system

Simply put, paralysis disrupts the bowel system. There are two main types of neurogenic bowel dysfunction, depending on level of injury: an injury above the conus medullaris (at L1) results in upper motor neuron (UMN) bowel syndrome; a lower motor neuron (LMN) bowel syndrome occurs in injuries below L1.

In a UMN or hyperreflexic bowel, voluntary control of the external anal sphincter is affected; the sphincter remains tight, which promotes constipation and retention of stool. This complication has been linked to episodes of autonomic dysreflexia. UMN connections between the spinal cord and the colon remain intact, thus reflex coordination and stool propulsion remain intact. Stool evacuation in people with UMN bowel occurs by means of reflex activity caused by a stimulus introduced into the rectum, such as a suppository or digital stimulation.

LMN or flaccid bowel is marked by loss of stool movement (peristalsis) and slow stool propulsion. The result is constipation and a higher risk of incontinence due to lack of a functional anal sphincter. To minimize the risk of hemorrhoids, use stool softeners, minimal straining during bowel efforts, and minimal physical trauma during stimulation.

Bowel accidents happen

The best way to prevent bowel accidents is to follow a schedule and teach the bowel when to have a movement.

Most people perform their bowel program at a time of day that fits with their lifestyle. The program usually begins with insertion of either a suppository or a mini-enema, followed by a waiting period of approximately 15-20 minutes to allow the stimulant to work. After the waiting period, digital stimulation is performed every 10-15 minutes until the rectum is empty. Those with a LMN or flaccid bowel frequently start their programs with digital stimulation or manual removal.

Bowel programs typically require 30-60 minutes to complete. Preferably, a bowel program can be done on the commode. However, those at high risk for skin breakdown need to weigh the value of bowel care in a seated position vs. a side-lying position in bed.

Constipation is a problem for many people with neuromuscular-related paralysis. There are several types of laxatives that help with constipation. Laxatives such as Metamucil supply the fiber necessary to add bulk, which makes it easier to move stool through the bowels. Stool softeners, such as Colace, also keep the water content of the stool higher, which keeps it softer and thus easier to move. Stimulants such as bisacodyl increase the muscle contractions (peristalsis) of the bowel, which moves the stool along.

Frequent use of stimulants can actually aggravate constipation – the bowels become dependent on them for even normal peristalsis.

The use of suppositories

There are two main types of suppositories, both based on the active ingredient bisacodyl: those with a vegetable base (e.g. Dulcolax) and those with a polyethylene glycol base (e.g. Magic Bullet). Bullets are said to be about twice as fast as the alternative.

Antegrade continence enema is an option for some people with difficult bowel problems. This technique involves surgery to create an opening (stoma), in the abdomen; this allows introduction of liquid above the rectum, thus causing an effective flushing of fecal material from the bowel. This method may significantly decrease bowel care time and allow for the discontinuation of some medications.

Facts for better digestive management

  • It is generally not necessary to have a bowel movement every day. Every other day is okay.
  • Bowels move more readily after a meal.
  • Fluid intake of two quarts daily aids in maintaining a soft stool; warm liquid will also aid bowel movement.
  • A healthy diet including fiber in the form of bran cereals, vegetables and fruits helps keep the digestive process working.
  • Activity and exercise promote good bowel health.

Some medications commonly used by people with paralysis can affect the bowel. For example, anticholinergic medications (for bladder care) may result in constipation or even bowel obstruction. Additionally, there are several medications that can lead to constipation like antidepressant drugs, such as amitryptyline; narcotic pain medications; and some drugs used for the treatment of spasticity, such as dantrolene sodium.

Many people report significant improvements in quality of life after colostomy. This surgical option creates a permanent opening between the colon and the surface of the abdomen to which a stool collection bag is attached. Colostomies sometimes become necessary because of fecal soiling or pressure sores, continual stool incontinence, or excessively long bowel programs. It enables many people to manage their bowels independently, plus, colostomy takes less time than bowel programs.

Studies have shown that people who get colostomies are pleased and would not reverse the procedure.

While many may not have embraced the idea of a colostomy at the outset, the procedure can make a huge difference in quality of life, cutting bowel time from as much as eight hours a day to no more than 15 minutes.

Resources on bowel care

If you are looking for more information on ALS or have a specific question, our information specialists are available business weekdays, Monday through Friday, toll-free at 800-539-7309 from 9am to 5pm ET.

For more information on understanding your bowel system and additional resources from trusted Reeve Foundation sources, please download our fact sheet on bowel care and check out our repository of fact sheets on hundreds of topics ranging from aging with a spinal cord injury to secondary complications of paralysis.

Sources: University of Alabama at Birmingham, University of Washington School of Medicine, ALS Association, National Multiple Sclerosis Society

This project was supported, in part by grant number 90PR3002, from the U.S. Administration for Community Living, Department of Health and Human Services, Washington, D.C. 20201. Grantees undertaking projects under government sponsorship are encouraged to express freely their findings and conclusions. Points of view or opinions do not, therefore, necessarily represent official Administration for Community Living policy.