GI Dysfunction in Parkinson's Disease

Problems with the gastrointestinal tract have been long recognized as part of the symptoms of Parkinson’s disease. In fact in James Parkinson’s first description of this condition dating back to 1817, he makes mention of drooling, trouble swallowing and constipation as being part of this disease. Unfortunately for decades, there was very little attention paid to these issues even though they can significantly affect a person’s quality of life.

Swallowing and digesting our food is something we take for granted, it just seems to happen automatically with very little thought or effort on our parts. In reality however, the gastrointestinal system is much more complicated and involves our central nervous system (brain and spinal cord), our autonomic nervous system (the part of the nervous system that is responsible for involuntary functions such as our heart beating or our intestines moving) and the enteric nervous system (those nerves responsible for gastrointestinal functioning – essentially our “gut’s brain”). Successful communication between all these systems is necessary in order for everything to work as it should.

What goes wrong in Parkinson’s disease? It’s not clear. While the motor symptoms of Parkinson’s are a result of damage to the dopamine producing cells in the part of the brain called the substantia nigra, the dysfunction we see in the GI tract is a bit more complicated. Some of the problems we experience such as difficulty swallowing may be in part due to the stiffness and slowness of muscles that we normally relate to Parkinson’s. But investigators have also shown that the first changes or cell damage related to Parkinson’s actually may occur in the gastrointestinal tract itself and that the brain changes that we see may actually come much later.

We also know from studies that constipation may in fact be a premotor symptom or early sign of Parkinson’s disease. That is to say that individuals who develop Parkinson’s are more likely to have a history of constipation. This is not to say that everyone with constipation develops Parkinson’s.

Parkinson’s disease can have a wide range of effects on the gastrointestinal tract which extends from the mouth to anus and is about 8.3 m (or 27 feet) long. The most common manifestations are:

- dental deterioration

- excess saliva

- difficulty swallowing (dysphagia)

- slow emptying of the stomach (gastroparesis)

- poor movement of the bowel (intestinal dysmotility)

- difficulty emptying the bowel (anorectal dysfunction)

Like most nonmotor symptoms, problems with the digestion and elimination can really affect a person’s quality of life. And these issues need first to be recognized and then managed effectively, the best results usually seen when managed by a team of various health professionals.