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What is Myasthenia Gravis?

Myasthenia Gravis (MG) is a rare autoimmune disorder of neuromuscular transmission. Antibodies in the body attack structural components of the Neuromuscular Synapse, i.e. the point at which nerve impulses are transmitted from the motor nerve ending to the muscle. This attack results in muscle weakness of the skeletal muscles.

How common is Myasthenia Gravis?

MG is a rare disease. It affects 9 to 30 / million / year. The distribution of MG occurrence is related to age and gender. At younger ages, <40 years, it is more common in women and at older ages, >50 years, there is a slight predominance in men.

What is the main characteristic of MG?

The main clinical characteristic of MG is the appearance of muscle weakness with fatigue and its improvement with rest. Also, the fluctuation of symptoms is characteristic, with worsening at the end of the day.

What are the forms of MG?

• Ophthalmic: symptoms are limited only to the eyes. Diplopia and blepharitis are the first symptom in the majority of patients with MG (50% – 80%)
• Prolongitudinal: weakness of the prolongitudinal muscles (i.e. of the oropharynx). Patients experience difficulty in articulating words (dysarthria), change in the timbre of the voice with fatigue (as if speaking “through the nose”), dysphagia, regurgitation of fluids and their exit from the nose during swallowing and weakness in chewing after fatigue. The drooping of the lower jaw (“drooping jaw”) is also characteristic
• Generalized: weakness of the muscles of the arms and legs and/or the respiratory muscles and/or the neck muscles (the patient cannot support his head).

What is Myasthenic Crisis?

Myasthenic crisis is considered to be experienced by patients with known myasthenia, who present a worsening of the disease and require mechanical respiratory support. Most attacks (75%) occur in the first 2 years of the disease.

How is MG diagnosed?

The diagnosis is made by a specialist neurologist, who, based on the history and clinical examination, will request further tests. These are: blood test for specific antibodies, electroneurogram / electromyogram and chest CT scan. The CT scan is done to reveal thymoma that often coexists with MG.

What are the available treatments for MG?

The treatment of MG includes symptomatic treatment, i.e. drugs to treat the symptoms (Mestinon) and immunomodulatory treatment, i.e. drugs (such as cortisone, azathioprine, mycophenolate, plasmapheresis, intravenous gamma globulin) that prevent the antibodies from attacking the neuromuscular junction. Finally, in the event that a thymoma is present, surgical removal is often recommended, which leads to improvement of the disease.