A person with paralysis can have a bowel movement, but not automatically. Spinal cord injury (SCI) disrupts the nervous system’s communication pathways, leading to neurogenic bowel dysfunction. This condition causes the loss or alteration of the body’s automatic signals for elimination. Managing this condition requires a proactive, scheduled approach rather than relying on natural body cues. The level and completeness of the spinal cord injury determine the specific nature of the dysfunction, necessitating a highly individualized management plan.
How Paralysis Affects the Digestive System
The process of digestion relies on a sophisticated network of nerves that coordinate muscle contractions throughout the gastrointestinal tract. This involuntary, wave-like muscle movement, called peristalsis, propels waste through the colon and into the rectum. When a spinal cord injury occurs, the brain loses its direct communication link with the lower digestive tract.
This disruption means the brain can no longer receive the sensory signal that the rectum is full, nor can it send the voluntary command to the external anal sphincter to relax for elimination. The result is significantly slowed colonic transit. Slower movement allows too much water to be absorbed from the waste, frequently leading to constipation and the formation of hard, dry stool. The loss of voluntary control over the sphincter muscle means that elimination is often unpredictable, leading to the risk of unplanned evacuation.
Understanding Different Types of Neurogenic Bowel
Neurogenic bowel dysfunction is categorized into two main types, distinguished by the location of the spinal cord injury. These classifications dictate the strategy of the bowel management program. Injuries that occur above the T12 vertebral level typically result in a reflexic, or upper motor neuron (UMN), bowel.
With a reflexic bowel, the defecation reflex arc remains intact within the spinal cord, but it is no longer under the control of the brain. This often leads to a spastic or tight anal sphincter, causing stool retention in the rectum. Elimination can be triggered by rectal stimulation, but it risks unplanned evacuation if the rectum becomes overly full.
Conversely, injuries at or below the T12/L1 level result in a flaccid, or lower motor neuron (LMN), bowel. The flaccid bowel is characterized by a damaged reflex arc and a loose, or atonic, anal sphincter. Because the nerves controlling the reflex are damaged, the bowel has reduced peristalsis and cannot be easily stimulated to empty. The loose sphincter also means that stool may leak out continuously, making daily management necessary to prevent incontinence.
Establishing a Bowel Management Program
A bowel management program is established to achieve predictable, complete, and safe elimination. The program should be scheduled regularly, often every other day for a reflexic bowel or daily for a flaccid bowel, at a time that works best with a person’s routine. Scheduling the procedure about 20 to 30 minutes after a meal utilizes the gastrocolic reflex, the natural movement of the colon stimulated by eating.
Dietary factors are important, focusing on achieving a soft, formed stool consistency. Adequate fluid intake is necessary to prevent stool from becoming hard and dry. Fiber from sources like fruits, vegetables, and whole grains adds bulk and aids movement. A health professional typically determines the appropriate fiber level, as excessive fiber without sufficient fluid can worsen constipation.
For those with a reflexic bowel, the procedure involves chemical stimulation using a suppository or mini-enema to initiate the reflex contraction. This is followed by digital stimulation, where a lubricated, gloved finger is gently inserted into the rectum to prompt the internal sphincter to relax and start the emptying process. Managing a flaccid bowel often relies on manual removal of stool, as the reflex cannot be triggered. Positioning is also an important technique, as sitting upright on a commode or toilet seat allows gravity to assist in the evacuation process.
Recognizing Potential Bowel-Related Health Risks
Poorly managed neurogenic bowel function poses several health risks. Chronic constipation can progress to fecal impaction, where a mass of hard stool becomes lodged in the rectum and cannot be passed. This requires urgent medical intervention and can cause significant abdominal pain and distension.
In individuals with spinal cord injuries at or above the T6 level, a full bladder or bowel is a frequent trigger for Autonomic Dysreflexia (AD). AD is characterized by a rapid, uncontrolled surge in blood pressure that the nervous system cannot regulate below the injury site. Symptoms include a pounding headache, sweating above the level of injury, and a flushed face. If not treated immediately by removing the stimulus, it can lead to stroke or seizure.
Furthermore, frequent, intrusive interventions like digital stimulation or manual removal carry the risk of trauma to the delicate rectal tissue. Consistent pressure can lead to complications such as hemorrhoids and anal fissures, which can cause bleeding and pain. Working closely with a healthcare team is necessary to ensure the bowel program is effective, predictable, and minimizes these medical complications.