My 70-year-old cousin developed problems with her speech and one of her eyelids started to droop. We thought she had suffered a stroke, but she’s been diagnosed with myasthenia gravis. What is this?
Normally, impulses travel down a nerve, causing the nerve endings to release a neurotransmitter called acetylcholine. This chemical is involved in triggering muscle contractions.
In myasthenia gravis (MG), antibodies block or destroy the receptors for acetylcholine, preventing the muscle from working properly. These antibodies are produced by the body’s own immune system. Myasthenia gravis is therefore called an autoimmune disease because the immune system mistakenly attacks itself.
The thymus gland, which lies in the chest area beneath the breastbone, forms part of the body’s normal immune system. It is thought that there is a relationship between the thymus gland and myasthenia gravis.
The condition can affect both sexes, at any age, but more commonly affects young adult women under the age of 40 and men over 60. About 80 per cent of MG sufferers are over the age of 55.
While not a hereditary disease, in some cases more than one member of a family can be affected. In Ireland, there are almost 400 diagnosed sufferers of MG. However, it is thought that many more sufferers go undiagnosed.
Her symptoms came on very quickly. Is this usual?
Symptoms of MG may develop suddenly and can vary in type and severity. The condition typically affects the muscles that control eye and eyelid movement, facial expression and swallowing.
It may cause drooping of one or both eyelids, blurred or double vision and a change in facial expression. Weakness in the arms, hands, fingers, legs and neck may develop and the person’s gait may become unsteady.
Some sufferers experience impaired speech and shortness of breath. In severe form, it may affect the muscles that control breathing.
Is it a painful condition and what can be done to treat it?
Although myasthenia gravis can be very debilitating, it tends not to cause pain. While there is no cure for the condition, some treatments can bring about improvements.
Medications that help transmission between the nerves and muscles and drugs that suppress the immune system may help.
Surgical removal of the thymus gland (thymectomy) and plasma exchange (plasmapheresis) may be recommended for some sufferers.
With treatment, some MG sufferers go into permanent or temporary remission and symptoms completely disappear.
