Myasthenia gravis is an autoimmune disease in which the body's own immune system disrupts communication between nerves and muscles. Antibodies block the receptors on the muscle, so that nerve signals no longer arrive in full. The result is an exertion-dependent muscle weakness that increases over the course of the day. The eye muscles are particularly often affected, and frequently the first to be involved.
In ocular myasthenia the weakness is confined to the eye muscles and the lid elevators. About half of the patients who begin with eye symptoms nevertheless develop a generalised form within two years, in which the muscles of the arms, legs, face or airways can also be involved.
Diagnosing myasthenia gravis can be demanding, since the symptoms fluctuate. The following investigations help to confirm it:
Treatment aims to improve neuromuscular transmission and to control the immune response:
Where the thymus gland is enlarged or abnormal, a thymectomy (surgical removal) can be considered. In many patients this procedure leads to a long-term improvement in symptoms.
Surgical correction of ptosis or an eye misalignment is only considered once the disease has been stable for one to two years. Because the muscle weakness can fluctuate, operating too early would carry an unpredictable result.
The condition requires long-term medical care. With well-adjusted treatment, most of those affected lead a largely normal life. It is important to know the warning symptoms of deterioration, particularly difficulty swallowing or breathing, and to seek medical help immediately. Ophthalmological check-ups serve to adjust prism lenses for double vision and to monitor the eye muscles.