An update on myasthenia gravis

Abstract

Myasthenia gravis (MG) is an autoimmune disease characterised by autoantibodies against acetylcholine receptors at neuromuscular junctions, resulting in defective neuromuscular transmission. The characteristic features are fatigability and fluctuating weakness of skeletal muscles. It commonly presents with diplopia or unilateral ptosis, which are worse in the evenings. Respiratory muscle weakness may result in respiratory failure. MG is associated with various autoimmune diseases, and thymic hyperplasia or thymoma. An early diagnosis depends on a high index of suspicion, and is confirmed using tensilon test, and electromyography (EMG), and by a raised acetylcholine receptor antibody titre. Symptomatic treatment consists of cholinesterase inhibitors, corticosteroids and other immunosuppressants. Plasmapheresis or pooled intravenous human IgG (IVIgG) provides rapid but short-term relief for acute exacerbations. Thymectomy provides long-term control for patients with thymic hyperplasia, and is essential for thymomas.