I have read that infections--especially long-lasting, untreated infections--can trigger autoimmune diseases. So if someone has Lyme for a long time, it can lead to MG. Then the person has both Lyme and MG.

So if a person has a diagnosis of MG, and then is discovered to have Lyme disease, I would be careful not to assume it was Lyme and only Lyme all along. How was the diagnosis of MG made? Lyme doesn't cause the antibodies that a blood test for MG looks for. Lyme doesn't causes a positive SFEMG. I've never heard of the symptoms of Lyme responding to Mestinon or Tensilon. Also, I know that Lyme symptoms can vary greatly (and so can MG symptoms), but there are MG symptoms that don't appear on the Lyme list, and Lyme symptoms that don't appear on the MG list.

Abby