Myasthenia gravis

Myasthenia gravis is a rare autoimmune disease. It causes weak muscles and tiredness. Stress and hot weather can make the symptoms worse. It also gets worse with activity.

Myasthenia gravis is caused by the immune system attacking the nerves that tell muscles to contract. It is treated in two main ways. First, a drug can be given to slow down (suppress) the immune system using an immunosuppressant like steroids. Alternatively, a drug can be given to turn up the signal that tells muscles to contract. The signal for contracting is a chemical the body makes called acetylcholine. This signal is 'turned up' by blocking acetylcholine breakdown - these drugs are called acetylcholinesterase inhibitors.