Myasthenic crisis induced by chemotherapy in treatment of invasive thymoma.

Myasthenia gravis (Paralysis Suna non Habitualis) is a neuromuscular disease, characterized by fluctuating weakness of skeletal muscles, which is increased by use, at least partially relieved by rest and improves specifically by anticholinesterases. Myasthenic crisis is a life threatening condition in which there is sudden failure in respiratory function due to muscle weakness. It starts with occurrence of short attacks of dyspnoea, frequently with inspiratory strider, increasing bulbar weakness, restlessness, insomnia, tachycardia and hypertension. Infectious diseases, fever, psychologic stress, hypoor hyperthyroidism, extremes of weather and certain drugs (anesthetics, muscle relaxants, anticonvulsants, antiarrythmics and even some antibiotics) can precipitate the myasthenic crisis. We report a patient of invasive malignant thymoma (Stage III) who developed acute myasthenic crisis after the first dose of chemotherapy.