Multiple Sclerosis (MS) is an autoimmune disease where the immune system attacks the central nervous system (CNS), specifically the protective myelin sheath surrounding nerve fibers. This damage disrupts the transmission of electrical signals, leading to a wide range of neurological symptoms. Gastroparesis, also called delayed gastric emptying, is a disorder where the stomach muscles function poorly, preventing food from moving into the small intestine at a normal rate. Research confirms that MS can cause gastroparesis by extending its neurological impact beyond the brain and spinal cord.
The Neurological Mechanism of Delayed Emptying
The link between Multiple Sclerosis and delayed gastric emptying lies in the Autonomic Nervous System (ANS), which regulates involuntary bodily functions, including digestion. A specific component of the ANS, the vagus nerve, transmits signals from the brainstem to the stomach muscles, coordinating the contractions necessary to propel food forward. MS-related demyelination, or the loss of the myelin sheath, can occur in the brainstem, which is the origin point for the vagus nerve.
Damage to the vagal nerve nuclei in the brainstem interrupts the communication pathway between the CNS and the stomach. This disruption prevents the stomach muscles from contracting with the proper strength and rhythm needed for gastric motility. Without this motor function, food remains in the stomach for an extended period. Demyelination may also affect the balance between the vagus nerve’s parasympathetic input and the sympathetic nervous system’s inhibitory signals, further slowing gastric emptying.
Identifying Gastrointestinal Symptoms
A person with MS who develops gastroparesis will experience specific upper gastrointestinal symptoms. The most common complaints include feeling full quickly after starting a meal, known as early satiety, and persistent nausea. Vomiting is also characteristic of the condition, often involving undigested food consumed several hours earlier.
Other symptoms include abdominal pain, general bloating, and abdominal distention. For those with diabetes, which can co-occur with MS, gastroparesis can cause unpredictable fluctuations in blood sugar levels due to the erratic timing of nutrient absorption. These digestive issues can sometimes be mistakenly attributed to general MS-related fatigue or as side effects from medications used to manage MS, which can delay diagnosis.
Diagnostic Procedures and Management Strategies
The process of confirming gastroparesis in an MS patient first involves ruling out a mechanical obstruction, which can mimic the symptoms. This is typically done through an upper endoscopy, where a flexible tube with a camera is used to examine the upper digestive tract. Once an obstruction is excluded, the standard for diagnosis is the Gastric Emptying Scintigraphy (GES) test.
During a GES, the patient consumes a meal containing a small amount of a radioactive tracer. A special camera tracks the rate at which the stomach empties over a period of up to four hours. Gastroparesis is determined if a significant amount of the tracer meal remains in the stomach after four hours.
Management focuses on improving stomach motility and ensuring adequate nutrition, requiring a coordinated effort between the patient’s neurologist and gastroenterologist. Dietary modifications are a primary treatment and involve eating small, frequent meals throughout the day instead of three large ones. Patients are advised to consume food low in fat and fiber, as these components slow down gastric emptying.
Medications called prokinetics, such as metoclopramide, are often prescribed to stimulate stomach muscle contractions and accelerate the movement of food. For severe cases that do not respond to initial treatments, more advanced interventions may be necessary to maintain nutrition. These options include the use of a jejunostomy feeding tube, which bypasses the stomach entirely to deliver nutrients directly into the small intestine. Another possibility is gastric electrical stimulation, which involves surgically implanting a device that sends mild electrical impulses to the stomach muscles to encourage contractions.