Multiple Sclerosis (MS) is a chronic condition where the immune system attacks the protective myelin sheath surrounding nerve fibers in the central nervous system. This damage disrupts communication pathways between the brain and the body, leading to a wide variety of symptoms. While MS is often associated with mobility and vision problems, gastrointestinal dysfunction is a common, yet frequently unaddressed, consequence. Bowel issues significantly affect a person’s comfort, daily activities, and overall quality of life, making effective management crucial.
Understanding Bowel Issues in MS
Bowel dysfunction in people with MS is a highly prevalent issue, affecting an estimated 39% to 73% of individuals. This problem is broadly referred to as neurogenic bowel dysfunction, indicating its origin in the damaged nervous system. The most frequent manifestation is chronic constipation, reported by approximately 43% to 50% of patients, involving infrequent movements or difficulty passing stools.
Fecal incontinence is also common, involving the unintended leakage of stool or gas due to a lack of anal sphincter control. Up to 50% of MS patients experience this occasionally. Constipation and fecal incontinence often occur together, as severe constipation can paradoxically lead to incontinence when liquid stool leaks around an impacted mass.
The Neurological Basis of Dysfunction
The primary cause of bowel problems is direct damage from demyelination and lesions within the central nervous system. Lesions in the spinal cord and brain interfere with the nerve signals that regulate gut movement and sensation. This disruption slows down peristalsis, the muscular contractions that propel waste through the colon. Sluggish movement allows the colon to reabsorb too much water, resulting in hard, difficult-to-pass stools.
Nerve damage also impairs the body’s ability to recognize the urge to defecate and reduces voluntary control over the anal sphincter muscles. This loss of sensation contributes directly to both constipation and incontinence. The severity of bowel symptoms often correlates with the degree of neurological disability.
Secondary symptoms of MS further exacerbate the problem. Fatigue and reduced mobility limit the physical activity that naturally stimulates the gut, contributing significantly to slowed intestinal transit time. Certain medications prescribed for other MS symptoms can also be contributing factors, including anticholinergics, baclofen, tricyclic antidepressants, and opioid pain relievers.
Lifestyle and Dietary Management Strategies
Initial management focuses on specific adjustments to diet and daily habits. Increasing fiber intake is foundational, as it adds bulk to the stool and stimulates movement through the colon. Fiber should come from a variety of sources, including fruits, vegetables, legumes, and whole-grain products.
Fiber must be added gradually to prevent excessive bloating or gas. For individuals with limited mobility, a daily target of up to 30 grams of fiber may be needed to maintain regular function. Adequate fluid intake is equally important, as fiber requires water to soften the stool and work effectively.
A daily fluid intake of approximately 48 to 64 ounces (six to eight glasses) is generally recommended. Water is the best choice, and it is advisable to limit drinks containing high amounts of caffeine or alcohol, as these can irritate the bowel or contribute to dehydration.
Incorporating physical activity helps stimulate the muscles of the digestive tract. Even if mobility is limited, chair-based exercises, gentle stretching, or short walks encourage gut motility. Abdominal massage, performed in a circular motion following the path of the colon, is another non-pharmacological technique that can help move stool along.
Establishing a consistent bowel retraining program is highly effective for encouraging regularity. This involves selecting a specific time each day, often 15 to 30 minutes after a meal, to sit and attempt a bowel movement. Utilizing proper positioning, such as placing the feet on a step stool to elevate the knees above the hips, can facilitate easier evacuation.
Medical and Clinical Interventions
When lifestyle and dietary changes are insufficient, a stepwise approach moves to pharmacological and clinical interventions. Over-the-counter laxatives are commonly used and fall into several categories based on their mechanism of action.
Bulk-forming agents, such as psyllium, absorb water to increase stool volume, working best when accompanied by plenty of fluid. Osmotic laxatives, like polyethylene glycol, draw water into the colon, which softens the stool and promotes a bowel movement. Stimulant laxatives, such as bisacodyl or senna, directly cause the intestinal muscles to contract, and are often reserved for short-term use.
For more refractory cases of constipation, a physician may prescribe newer oral treatments. These include secretagogues, which increase fluid secretion into the intestines, or prokinetic agents, such as prucalopride, that stimulate the gut’s natural muscular contractions. These prescription options are considered when first-line therapies have proven insufficient.
In situations requiring immediate relief or advanced management, interventional techniques may be necessary. Rectal suppositories or small-volume enemas can be used to stimulate the lower bowel and trigger an evacuation. For chronic, severe issues, a specialist may suggest procedures like transanal irrigation or biofeedback therapy to help retrain pelvic floor muscles.