Parkinson’s disease is a neurodegenerative condition known for affecting movement, but its impact extends to non-motor functions as well. Among the most prevalent of these is constipation, which affects a significant majority of individuals with Parkinson’s, often appearing years before the characteristic motor symptoms emerge. The connection is not coincidental but is rooted in the same disease processes that affect motor control.
The Underlying Connection Between Parkinson’s and Constipation
The primary reason for constipation in Parkinson’s disease lies in the malfunction of the autonomic nervous system. This system manages involuntary bodily functions, including the rhythmic muscle contractions, known as peristalsis, that move food through the digestive tract. In Parkinson’s, the nerve cells that control these automatic actions can be impaired, leading to a slowdown of the gastrointestinal system, which means waste remains in the colon longer, allowing more water to be absorbed and resulting in stools that are hard and difficult to pass.
This digestive slowdown is directly linked to dopamine, the neurotransmitter depleted in the brains of Parkinson’s patients. Dopamine is also a regulator of digestive processes within the enteric nervous system, often called the “gut’s brain.” The loss of dopamine-producing neurons disrupts the coordination of intestinal muscles, contributing to slowed gut motility.
Further research has illuminated a “gut-brain axis,” suggesting a two-way communication system between the gastrointestinal tract and the brain. Some evidence indicates that for certain individuals, the disease pathology of Parkinson’s, characterized by the accumulation of a protein called alpha-synuclein, may begin in the gut’s nerve cells. These protein clumps, called Lewy bodies, have been found in the neurons of the intestines in people with Parkinson’s, sometimes appearing before motor symptoms develop. This suggests that damage to the gut’s nervous system could be an early event in the disease process.
Management and Treatment Approaches
Managing constipation in Parkinson’s disease begins with lifestyle and dietary adjustments. A primary strategy is to increase dietary fiber, which adds bulk to stool and facilitates its passage. Good sources of fiber include whole-grain breads, bran, legumes, fruits, and vegetables. It is important to increase fiber intake gradually and to ensure it is paired with adequate fluid intake—at least six to eight glasses of water daily—as fiber without enough liquid can worsen the problem.
Regular physical activity is another part of management. Exercise, even gentle activities like walking, helps stimulate the abdominal muscles and promotes more regular bowel contractions. Establishing a consistent toilet routine, such as attempting a bowel movement at the same time each day, can also be beneficial. For some, using a small footstool to elevate the knees above the hips while on the toilet can create a more natural angle for defecation and reduce the need for straining.
When lifestyle changes are insufficient, over-the-counter (OTC) options are considered, though they should be discussed with a healthcare provider. Stool softeners, like docusate, work by allowing more water to mix with the stool, making it softer. Osmotic laxatives, such as polyethylene glycol (Miralax), function by drawing more water into the intestines from the surrounding tissues, which helps to soften stool and stimulate a bowel movement. These are considered gentle and suitable for regular use.
Stimulant laxatives, like senna or bisacodyl, work by triggering contractions in the intestinal muscles to move stool along. These are recommended for short-term use, as the digestive system can become dependent on them. If OTC remedies do not provide relief, a doctor might recommend prescription medications. Options like lubiprostone, linaclotide, or prucalopride work through various mechanisms to increase fluid in the intestines or enhance gut motility.
The Role of Parkinson’s Medications
The management of Parkinson’s symptoms can sometimes complicate constipation. Certain medications prescribed to treat the motor symptoms of the disease can themselves contribute to or worsen constipation. This is particularly true for a class of drugs known as anticholinergics, such as trihexyphenidyl, which are sometimes used to control tremors. These drugs work by blocking the neurotransmitter acetylcholine, but a side effect of this action is the slowing of intestinal muscle contractions.
Other medications used for Parkinson’s, including levodopa and dopamine agonists, can also list constipation as a potential side effect. This creates a balancing act for neurologists, who must weigh the benefits of a medication for motor control against its potential to exacerbate non-motor symptoms like constipation.
It is important for individuals to communicate with their healthcare provider about any side effects they experience. Patients should not stop or change the dosage of their prescribed Parkinson’s medications on their own, as this can interfere with the management of their motor symptoms. Instead, a doctor can help navigate these challenges by adjusting the dosage, trying a different medication, or implementing management strategies to counteract the side effects.
Potential Complications and When to Seek Medical Help
Chronic, unmanaged constipation can lead to more serious health issues. The discomfort from bloating, abdominal pain, and a persistent feeling of fullness can reduce appetite, potentially leading to unintended weight loss. Over time, severe constipation can result in fecal impaction, a condition where a hard mass of stool becomes stuck in the colon or rectum and cannot be passed normally.
In rare instances, fecal impaction can lead to a bowel obstruction, which is a medical emergency. Another risk, though less common, is toxic megacolon, a severe inflammation and widening of the colon that can be life-threatening. The pressure from a severely backed-up colon can also affect bladder control, leading to urinary incontinence or an increased frequency of urinary tract infections.
You should contact a doctor or go to an emergency room if you experience any of the following symptoms:
- Severe abdominal pain or bloating
- Nausea and vomiting
- An inability to pass any stool or gas
- Rectal bleeding