Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that targets motor neurons in the brain and spinal cord. These motor neurons control all voluntary muscle movement, including walking, speaking, and breathing. As the disease advances, these nerve cells degenerate and die, causing muscles to weaken and leading to a progressive loss of movement control. Given this widespread loss of muscle function, the question of whether a person with ALS loses control of their bowels is a common concern for those affected and their caregivers.
The Direct Answer: Bowel Control and ALS
The primary control over bowel function is preserved in people living with ALS because the disease primarily affects motor neurons governing voluntary muscles. Bowel function is largely controlled by the autonomic and enteric nervous systems, which regulate involuntary actions like intestinal contractions (peristalsis). The internal anal sphincter, a smooth muscle, is not directly controlled by the motor neurons destroyed in ALS. Although the external anal sphincter is a voluntary muscle, the neural pathways controlling primary bowel function are often spared. Therefore, stool incontinence is rare, and the issue is typically secondary complications arising from the physical progression of the disease.
Primary Related Elimination Issue: Constipation
While neurological control is preserved, chronic constipation is a frequent and significant complaint among ALS patients, affecting up to half of those with the disease. This problem stems from physical effects of ALS rather than a direct attack on the bowel itself. A major contributing factor is profound immobility, as a lack of physical movement significantly slows down gut motility. The muscles of the abdomen and pelvis also weaken, making elimination physically difficult.
The disease also frequently affects diet and hydration status. Difficulty swallowing (dysphagia) often leads to reduced intake of fluids and high-fiber foods necessary for soft stools. Furthermore, certain medications commonly used to manage ALS symptoms, such as pain relievers or drugs to control saliva, can dry out the stool. These factors combine to create a challenging environment for regular elimination.
Secondary Elimination Concerns: Urinary Function
Similar to the bowel, the primary function of the bladder is maintained in ALS, meaning the disease does not typically cause initial incontinence or retention. However, secondary issues impacting urinary function are common, with reports of bladder dysfunction affecting a significant percentage of patients. The most frequently reported problems are urinary urgency, frequency, and difficulty completely emptying the bladder. These symptoms can arise due to generalized weakening of the pelvic floor muscles or spasticity in the lower limbs.
The physical demands of toileting also contribute to the concern. As mobility decreases, a person may be unable to quickly reach the bathroom when the urge strikes, leading to accidents. Difficulty transferring can result in incomplete voiding, which contributes to urinary retention. This inability to quickly respond to the bladder’s signal is often a greater challenge than a direct neurological failure.
Strategies for Managing Elimination Issues
Managing elimination issues requires a proactive and multi-faceted approach focused on non-medical interventions and adaptive support. Optimizing hydration is a core strategy, as proper fluid intake is necessary for softening stool, especially when increasing fiber. Patients should aim for consistent fluid intake, potentially using thickened liquids or a feeding tube to ensure adequate daily amounts. Increasing dietary fiber is also important, but this must be done gradually and with sufficient fluid to prevent blockages.
Establishing a consistent bowel routine can significantly improve regularity and comfort. This involves selecting a scheduled time for toileting, often in the morning or after a meal, to take advantage of the body’s natural digestive reflexes. Gentle, passive range-of-motion exercises or light physical activity, if possible, can help stimulate gut motility. Adaptive equipment plays a large role in managing physical limitations, including the use of bedside commodes, raised toilet seats, or specialized positioning aids.