Myasthenia Gravis Support Group

Myasthenia gravis (MG) is a neuromuscular disease leading to fluctuating muscle weakness and fatiguability. The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity and improves after periods of rest. Although myasthenia gravis may affect any voluntary muscle, muscles that control eye and eyelid movement, facial expression, and...

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Change in bowel

BB3
BB3

Hi, 


I know it’s normal for diarrhea to be extreme with taking pyridostigmine, but has anyone ever experienced the opposite? My father has had diarrhea since having colon surgery 20 years ago. Recently diagnosed with MG, he now has firmer and less frequent stools. I’m curious if anyone else has experienced anything similar? TIA! 

Rhanson
Rhanson
Generally we think of MG as affecting the voluntary muscles and not the others (i.e. heart, digestive system). However the digestive system has both voluntary and involuntary muscles so some of it is affected
When we try to decide what symptoms (or changes) occur we try to separate medication side effects vs MG itself, and that can be very difficult. For most of us Mestinon is a potent stimulus to the digestive system, as you note, the opposite of what is happening with your father. Is he taking other meds that may have digestive changes as a side effect?
I took prednisone with mestinon and according to the side effects list -- prednisone can cause constipation or diarrhea,
There is a type of MG, called Lambert Eaton Myasthenic Syndrome that does include constipation as side effect. LEMS often is found in folks with cancer.
Some folks have more than one autoimmune problem and they may appear at the same time. At age 76, your father may have something else wrong.

There has been some research that shows there are changes in heart rhythms with MG, something that we are told is not changed by MG, so it is possible that digestive system changes may occur to from MG itself.
Looking back through this forum, there are a few folks who have said that they had similar changes too.

Finally, report the change to your doctors. Always they tell us to report changes in bowel movements as they can be indicators of other problems. Hopefully there is nothing wrong and the change for the better will continue. It would be nice if MG had some positive side effects!

Good Luck
Russ