. Symptoms are asymmetrical. (b) Limb weakness - may involve proximal or distal muscles. (c) Bulbar muscle weakness - leads to loss of facial expressi

following repetitive contraction with a tendency to recovery of motor power after a period of inactivity. (a) Ocular muscles - first to be involved causing double vision or ptosis. Symptoms are asymmetrical. (b) Limb weakness - may involve proximal or distal muscles. (c) Bulbar muscle weakness - leads to loss of facial expression, inability to whistle, difficulty with speech, chewing and swallowing. Weakness of neck muscles and jaw causes patient to use a hand to support his jaw. (d) Respiratory muscle involvement -can lead to shortness of breath and ventilatory failure in severe cases. Other precipitating factors -Emotional stress, pregnancy and infection apart from exercise can lead to exacerbation of symptoms. IMMUNE DISORDERS ASSOCIATED WITH MYASTHENIA GRAVIS - Rheumatoid arthritis, hyperthyroidism, hypothyroidism, polymyositis, SLE, pernicious anaemia, Sjogren's syndrome, pemphigus. Clinical types 1. Neonatal myasthenia - Transient illness in babies born to myasthenic mothers. 2. Juvenile myasthenia - in younger age group. 3. Eaton-Lambert myasthenic syndrome - often associated with bronchial carcinoma. Differs from true myasthenia thus - (i) Onset in later age. (ii) Power improves following exercise. (iii) Limb muscles more involved than ocular. (iv) Tendon reflexes usually diminished. (v) Poor response to treatment with neostigmine and abnormal sensitivity to decamethonium 4. Penicillamine-induced myasthenia - is similar to adult myasthenia gravis, and usually resolves over several months after drug withdrawal. 5. Congenital myasthenia - at or close to birth.