Multiple Sclerosis (MS) is a chronic condition where the immune system attacks the myelin sheath protecting nerve fibers in the central nervous system. This damage disrupts the brain’s ability to communicate with the rest of the body. Acid reflux, or Gastroesophageal Reflux Disease (GERD), occurs when stomach acid flows back into the esophagus, causing irritation and a burning sensation. Although MS is primarily a neurological disorder, people with MS report gastrointestinal symptoms, including indigestion and heartburn, at a significantly higher rate than the general population.
The Neurological Mechanism Linking MS and Reflux
The direct link between MS and acid reflux originates in the autonomic nervous system (ANS), which controls involuntary bodily functions like digestion. MS lesions in the brain and spinal cord disrupt the signaling pathways of the ANS. This damage can directly affect the vagus nerve, which regulates gastrointestinal motility.
Damage to the vagus nerve impairs the coordinated muscle contractions that move food through the digestive tract. This often leads to gastroparesis, where the stomach empties its contents much slower than normal. When the stomach retains food and acid for too long, pressure increases, raising the likelihood of acid backing up into the esophagus. MS is also associated with motility disorders of the esophagus, such as achalasia.
The proper function of the Lower Esophageal Sphincter (LES), the muscle valve between the esophagus and stomach, is also controlled by these signals. Lesions can impair the LES’s ability to contract fully, causing it to relax inappropriately or remain partially open. This allows stomach contents to reflux easily, especially when lying down, causing heartburn and regurgitation symptoms. This compromise of both gastric emptying and LES tone provides a direct mechanism for acid reflux in MS patients.
Secondary Factors Contributing to Digestive Issues
Beyond the direct neurological damage, several indirect factors related to MS management and symptoms can contribute to or worsen acid reflux. Medications used to manage MS symptoms can interfere with the digestive system’s protective mechanisms.
Muscle relaxants, commonly prescribed for spasticity, are known to chemically relax the LES, allowing acid to escape the stomach. Oral Disease-Modifying Therapies (DMTs), such as dimethyl fumarate, frequently cause gastrointestinal issues like nausea, abdominal pain, and indigestion. High doses of corticosteroids used to treat MS relapses can also irritate the stomach lining, increasing sensitivity to acid and contributing to heartburn.
Physical symptoms of MS also promote reflux by altering abdominal pressure. Reduced mobility and muscle weakness often lead to prolonged periods of sitting or lying down, removing the benefit of gravity. Difficulty changing position, coupled with chronic constipation, increases pressure within the abdomen. This sustained intra-abdominal pressure physically forces stomach acid back up through a weakened LES.
Strategies for Managing Reflux in MS Patients
Managing acid reflux in MS requires an approach that addresses both neurological causes and secondary contributing factors. Lifestyle adjustments are key, starting with avoiding lying down for at least two to three hours after eating. Patients should also identify and limit common trigger foods, such as spicy, fatty, or acidic items, caffeine, and alcohol.
Elevating the head of the bed by six to eight inches is a practical measure that uses gravity to prevent nocturnal reflux. This is best achieved by placing blocks or specialized risers under the bedposts, or by using a wedge pillow that elevates the entire upper torso. For pharmacological management, Proton Pump Inhibitors (PPIs) and H2-blockers can effectively reduce stomach acid production.
Patients must review their current MS treatment regimen with their healthcare team, especially if symptoms begin after starting a new medication. Since muscle relaxants and DMTs can be major contributors, a physician may adjust the dosage or timing to reduce the impact on the LES and gastric motility. Addressing core MS symptoms, such as managing constipation or improving sitting posture, can also alleviate the abdominal pressure that exacerbates reflux.