What is Myasthenia Gravis (MG)? Myasthenia Gravis (pronounced My-as-theen-ee-a Grav-us), also know as “MG,” is a serious auto-immune neuromuscular disease that manifests itself by varying degrees of weakness in the body. For unknown reasons, the immune system of MG patients produces antibodies that attack the junction between the nerve and muscle cells. The impulse from a healthy nerve is blocked
or altered by these antibodies so it cannot reach the healthy muscle. This defect, along with a reduction of nerve receptor sites (There is as much as an 80% reduction in the number of these receptor sites with MG), causes fatigue and weakness of the myasthenic’s voluntary muscles. Occurrence
MG can appear in all races and in both sexes from infancy to senior citizen. The prevalence of MG in the United States is estimated to be about 20/100,000 population. However, MG is probably under diagnosed and the prevalence may be higher. Myasthenia Gravis occurs in all races, both genders, and at any age. MG is not thought to be directly inherited nor is it contagious. It does occasionally occur in more than one member of the same family. Our local Great Lakes Chapter of the Myasthenia Gravis Foundation, serving the state of Michigan, has approximately 550 patients on the mailing list. We know that more patients are out there either without a diagnosis, unaware of the chapter or choosing to not become a member. Treatment Options
There is no known cure for MG, but there are effective treatments available. Common treatments include medications, thymectomy (removal of the tymus gland) and plasmapheresis. Spontaneous improvement and even remission may occur without specific therapy. Treatment decisions are based on knowledge of the natural history of MG in each patient and the predicted response to a specific form of therapy. Treatment goals are individualized according to the severity of the MG weakness, the patient's age and sex, and the degree of impairment. Please contact our office for more in-depth brochures and information on treatment options. What are the symptoms of MG?
• Involuntary drooping eyelid(s) (ptosis)
• Blurred or double vision (diplopia)
• Slurred speech or nasal voice, usually after prolonged talking
• Difficulty chewing and swallowing
• Loss of facial expression, including the ability to smile
• Weakness in the arms and legs
• Chronic muscle fatigue
• Difficulty breathing
A patient may experience one, or a combination of these symptoms, and the severity varies from patient to patient. This variation has cause MG to be nicknamed the “snowflake” disease because no two patients present the same way or receive treatment in a uniform manner. Initially symptoms can often come and go, making diagnosis difficult. Diagnosis:
• Acetylcholine Receptor Antibody— a blood test for the abnormal antibodies can be performed to see if they are present..
• Anti-MuSK Antibody testing— a blood test for the remaining 15% of MG patients who have tested negative for the acetylcholine antibody.
• OfficeTests—Sleep, Ice Pack and Edrophonium tests are examinations performed by specialists to evaluate an improvement in strength that may be consistent with MG.
• Electromyography— (EMG) studies can provide support for the diagnosis of MG when characteristic patterns are present. Repetitive Nerve Stimulation is used to check for a pattern of response that is characteristic of MG.
• Single Fiber EMG— studies can provide support for the diagnosis of MG when characteristic patterns are present. The single fiber EMG and AChR antibody test are primary tests used to confirm a clinical diagnosis of MG. Sometimes all of these tests are negative or equivocal in someone whose story and examination still seem to point to a diagnosis of MG. A clinician skilled in recognizing MG and distinguishing MG from other conditions would need to determine if such a patient has MG or another disorder. There Is Hope
Due to advances in treatment, the future for a patient with MG is very bright. In some cases, MG may go into remission for a time period when no treatment is necessary. While there is much that can be done, there is still much more to learn to better understand MG. Research is ongoing and will continue until a cure is found.
