Parkinson’s disease is a complex neurological condition primarily recognized for its effects on movement. Beyond the more commonly known motor challenges, Parkinson’s disease can also influence a wide array of non-motor functions throughout the body. These non-motor symptoms often include various gastrointestinal issues, which can significantly impact an individual’s daily life.
Gastrointestinal Symptoms in Parkinson’s Disease
Gastrointestinal issues are frequently experienced by individuals with Parkinson’s disease, sometimes even preceding the onset of motor symptoms by many years. Constipation is the most commonly reported, affecting a significant majority, with prevalence estimates ranging from 50% to 80% or even up to 90% of those with the condition. This can involve reduced bowel movement frequency, difficulty passing stools, or a feeling of incomplete emptying.
Diarrhea, while less commonly attributed directly to the neurodegeneration of Parkinson’s disease itself compared to constipation, can occur. Sometimes, persistent constipation can lead to “overflow diarrhea,” where watery stool leaks around a blockage of harder, impacted stool. Diarrhea in people with Parkinson’s can also result from the same causes as in the general population, such as infections or food poisoning.
Factors Contributing to Diarrhea in Parkinson’s
Several factors can contribute to diarrhea in individuals with Parkinson’s disease. Medications used to manage Parkinson’s symptoms are a common source of gastrointestinal side effects. Levodopa, often combined with carbidopa and entacapone, can lead to diarrhea. Similarly, COMT inhibitors like entacapone and tolcapone, used to prolong levodopa’s effects, frequently list diarrhea as a side effect.
The autonomic nervous system, which controls involuntary bodily functions including digestion, is often affected in Parkinson’s disease. This dysfunction can lead to altered gut motility, such as gastroparesis (slowed stomach emptying) or slow transit through the intestines, which can predispose individuals to constipation that, in turn, may result in overflow diarrhea. Lewy bodies, protein clumps characteristic of Parkinson’s, are found in the nerve cells lining the gut, potentially disrupting normal digestive processes.
Emerging research also highlights the role of the gut microbiome, the community of microorganisms residing in the digestive tract. Alterations in the gut microbiota, known as dysbiosis, are observed in people with Parkinson’s and may influence gastrointestinal symptoms. Small Intestinal Bacterial Overgrowth (SIBO), characterized by excessive bacteria in the small intestine, is a type of dysbiosis that can cause symptoms like bloating and diarrhea.
When to Address Gastrointestinal Changes
Any significant or persistent change in bowel habits, including diarrhea, warrants discussion with a healthcare provider. Describe the nature of the diarrhea, its frequency, and any accompanying symptoms. This information helps the care team understand the potential underlying causes.
Persistent or severe diarrhea, particularly if accompanied by unexplained weight loss, fever, abdominal pain, or dehydration, requires prompt medical attention. These symptoms could indicate a more serious condition, such as an infection or another gastrointestinal disorder. Self-treating diarrhea, especially if it might be overflow diarrhea from constipation, can worsen it. Seeking professional medical advice ensures an accurate diagnosis and appropriate management plan.