


Virtually everyone with Parkinson’s disease has constipation, we now realize, and for some, constipation is a very early symptom, starting years or decades before any of the motor symptoms. And for some, constipation can be a severe, functionally limiting symptom requiring a variety of treatments.

Why do people with Parkinson’s disease have constipation? Because Parkinson’s disease affects the nerves in the “autonomic nervous system,” which is the part of the nervous system that takes care of things that should be “automatic.” As adults, we don’t worry about how to make our pupils constrict when we walk outside into the bright sun, or dilate when the room is dark—these things just happen automatically. When you eat food, you don’t have to turn a crank to get the food to move through the intestines—it just happens automatically. Except when it doesn’t.

There are nerves–think of them as electrical wiring–that run through the intestines, signaling the muscles in the intestines to contract in a smooth order, so that your food goes from stomach to small intestine to large intestine, to the rectum, where the waste products are collected and excreted. Parkinson’s leads to “short circuits” in that electrical system, as some of the nerves deteriorate or die out. Then food doesn’t move smoothly through the intestine, and the strong signal, that you should get when it is time for the waste products to be excreted, is reduced or completely lost, and the net result is—CONSTIPATION.

A research team in France has found that biopsies of the colon (taken during a colonoscopy procedure), processed using special methods to visualize the nerve cells, can help. They were able to detect Lewy bodies (little blobs of protein that collect only in the degenerating brain cells in people with Parkinson’s disease), in the nerve cells in the intestine. If other researchers can confirm these results, then it might be possible to “diagnose” Parkinson’s disease by colonoscopy!

This is interesting, but finding Lewy bodies in the nerve cells in the intestine will not immediately lead to a better treatment for constipation.

How can you get relief today?

Fortunately, there are lots of ways to help people with Parkinson’s disease who have constipation! Physical movement (exercise) helps, as does adequate fluid intake. Certain foods (particularly fruits with skin, and other fiber-containing fruits, vegetables, and grains) can stimulate the intestine, while others (bananas, cheese, and rice) tend to bind people up. Caffeine, in modest amounts, stimulates the intestine, while alcohol relaxes it. A number of over-the-counter products can also help. Senna-containing products, stool softeners, such as docusate, and “osmotic agents” such as sorbitol, lactulose, or polyethylene glycol, are the ones that we recommend most commonly. How much of which treatment you use depends on the results that you get, and how often you need to pass the bowels to feel comfortable.

It is important to treat constipation—if things slow down at the far end, they tend to slow up at the top end, too. People with untreated constipation lose their appetite, sometimes lose weight. And medications, such as levodopa, that need to get into the intestine in order to be absorbed, may get stuck in the stomach. And then the Parkinson’s motor symptoms will be worse.

So, don’t be embarrassed to talk to the doctor about your constipation. Your mobility may depend on it!


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