What Every Myasthenia Gravis Patient Should Know
MGF of Illinois Fall Seminar
Seventy-five people were on hand October 25 at Advocate Lutheran General Hospital in Park Ridge, Illinois to hear Matthew Meriggioli, MD, share the latest information about myasthenia gravis. Dr. Meriggioli, Professor of Neurological Sciences at Rush University Medical Center, explained current understanding on topics such as why people get autoimmune disease, what happens in the immune system of an MG patient, antibodies that cause MG, and prevalence of thymus abnormalities in MG patients.
Dr. Wayne Rubinstein, fellow member of MGF of Illinois’ Medical Advisory Board, provided support for the meeting and introduced Dr. Meriggioli. We’re grateful to both doctors, as well as to attendee Dr. Julie Rowin, for sharing their time and expertise. A DVD of the presentation will be available for purchase in February.
Here are highlights covered by Dr. Meriggioli.
In myasthenia gravis patients, about 75% are found to have thymus gland abnormalities. Of these, 85% have “hyperplasia,” which, according to the MedlinePlus, is enlargement due to increased cell production in normal tissue. The remaining 15% have a thymoma, which is a benign or cancerous tumor of the thymus.
There are various types of MG. At diagnosis, 85% of MG cases are related to the patient having acetylcholine receptor (AChR) antibodies. Another 8% of patients have MuSK (muscle-specific tyrosine kinase) antibodies, 5% have low-affinity AChR antibodies, and 1% have LPR4 (lipoprotein receptor-related protein 4) antibodies.
The course of myasthenia gravis weakness varies from person to person, as the following summary shows.
Eye muscle weakness 75%
Head/neck weakness 15%
Limb weakness 10%
Within first year
- Approximately 75% develop head/neck +/- limb weakness
- Approximately 67% reach maximum MG severity
- Approximately 20% experience MG crisis
The blood test for AChR antibodies has positive results for about 85% of MG patients, and for about 50% of those with ocular MG. In different patients, the test values do not correlate with severity of the disease. However, in a given patient, a change in the test values may correspond to a change in the disease.