Constipation is very common in Parkinson’s disease, affecting more than half of people with the condition at some point. This happens because Parkinson’s disease doesn’t just affect movement but also impacts the nerves that control the digestive system, especially the intestines.
Parkinson’s disease is primarily known for causing tremors, stiffness, and slow movement due to the loss of dopamine-producing cells in the brain. However, it also causes problems outside the brain, including the autonomic nervous system, which controls involuntary functions like digestion. The nerves that regulate the muscles in the gut become less effective, leading to slower movement of food through the intestines. This slow movement means stool stays longer in the colon, where more water is absorbed, making it hard and difficult to pass.
Another key reason constipation is common in Parkinson’s is the early involvement of the gut’s nervous system. Research shows that changes in the digestive tract can occur years before the classic motor symptoms appear. This suggests that Parkinson’s may start in the gut or at least affect it very early. The nerve cells in the gut, called the enteric nervous system, can accumulate abnormal proteins linked to Parkinson’s, disrupting normal gut function.
Besides nerve dysfunction, other factors contribute to constipation in Parkinson’s. Reduced physical activity due to stiffness and slow movement can decrease bowel motility. Medications used to treat Parkinson’s, especially those that affect dopamine, can also cause constipation as a side effect. Additionally, dehydration and poor dietary habits, which are common in people with Parkinson’s, worsen constipation.
Constipation in Parkinson’s is not just uncomfortable but also linked to other complications. It can affect the absorption of medications, making symptom control more difficult. Severe constipation can lead to bloating, abdominal pain, and even bowel obstruction in extreme cases. Moreover, constipation severity has been associated with faster progression of cognitive decline and dementia in Parkinson’s, indicating it may reflect more widespread nervous system involvement.
In summary, constipation in Parkinson’s disease arises mainly because the disease damages the nerves controlling the gut, slowing down bowel movements. This problem often starts early, sometimes decades before movement symptoms, and is worsened by reduced activity, medications, and lifestyle factors. Managing constipation is an important part of Parkinson’s care to improve quality of life and overall health.
