Myasthenia gravis is arare autoimmune disease, in which the function of the myoneural junction of the voluntary muscles is impaired Annual incidence is about 2-8/1 000 000. Symptoms include variable degrees of fatigue and weakness in voluntary musculature, which is aggravated by strain and relieved by rest. Two main types: limited to the eye muscles, or ocular (ca. 15% of the cases) generalised; the symptoms are usually most prominent in the proximal muscles of the shoulder and pelvic region. Treatment is the domain of a specialist in neurology. Remember that patients with myasthenia are very sensitive to drugs: check always the compatibility with myasthenia when starting a new drug for a myasthenic patient!