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Myasthenia Gravis

What is Myasthenia Gravis?

Myasthenia Gravis (MG) is a rare neurological disease. The immune system attacks and damages the nerve signal reception areas. This causes a breakdown between nerves and muscles and results in a loss of effectiveness and fatigue of the (skeletal) muscles. Any muscle can be affected but certain muscles and muscle groups are especially susceptible. In about two-thirds of MG patients the presenting problem is ocular (eye) muscle weakness.

What causes Myasthenia Gravis?

MG is a well-characterised, autoimmune disease of the neuromuscular junction, caused by antibodies to the muscle nicotinic acetylcholine receptor (AChR) and less frequently by antibodies to the neuromuscular junction protein (MuSK).

What is the frequency of Myasthenia Gravis?

MG occurs in all races, in both genders and at any age. It most commonly affects young adult women and older men. 600-700 people in Ireland are estimated to have Myasthenia Gravis; that is approximately 1 in 6,500 people.

How is Myasthenia Gravis diagnosed?

Investigations performed include:

  • Blood tests: blood samples are tested for raised AChR and MuSK antibodies.
  • Single-fibre electromyography (SF-EMG): is a study of muscle function. It involves recording action potentials from skeletal muscles using needle electrodes.
  • CT or MRI scan of the chest: this is to look for abnormalities of the thymus gland.

How is Myasthenia Gravis managed?

The main treatment for MG is medications and in some patients thymectomy (surgery to remove the thymus gland).


Useful Links:

Myasthenia Gravis Association (MGA) Ireland


Myasthenic Kids