(C) Myasthenia gravis # ENDOCRINE MYOPATHY:> Major categories of endocrine myopathy include those associated with Adrenal dysfunction (as in Gushing disease or steroid myopathy); Thyroid dysfunction (as in myxedema coma or thyrotoxic myopathy); Parathyroid dysfunction (as in multiple endocrine neoplasia); Pituitary dysfunction; and Islands of Langerhans dysfunction (as in diabetic myopathy from ischemic infarction of the femoral muscles).> Adrenal dysfunction: Aetiology of Hypoadrenalism: includes infection, inflammatory disease, and tumor. Adrenal failure may follow pituitary failure. In hypoadrenalism, neurological manifestations such as disturbances of behavior and mentation are prominent; myopathy is not likely to be a presenting finding. Factors contributing to muscle weakness in adrenal insufficiency include circulatory insufficiency, fluid and electrolyte imbalance, impaired carbohydrate metabolism, and starvation. The etiologies of hyperadrenalism include pituitary or ectopic overproduction of adrenocorticotropic hormone (ACTH), adrenal tumors, or exogenous corticosteroid administration. Pituitary ACTH hypersecretion (i.e., Cushing's disease) is caused by a corticotroph macroadenomas in 90% of patients and by a macroadenoma in most of the rest.> Hypoparathyroidism causes tetany, with or without carpopedal spasm.> Pathophysiology of Hypoparathyroidism may involve either deficiency of parathyroid hormone or inability of the hormone to have an effect at end-receptors because of dysfunction of the hormone receptors.> Hyperparathyroidism does not cause tetany but results in muscle wasting and myopathy (i.e., proximal muscle weakness). The pathophysiology is over secretion of hormone, frequently from a parathyroid adenoma.> Myasthenia gravis: Fluctuating weakness of commonly used voluntary muscles, producing, symptoms such as diplopia ptosis and difficulty in swallowing. Weakness of affected muscle increased by activity. Associated with thymic tumor or thyrotoxicosis and rheumatoid arthritis and lupus erythematosus. Other options are clearly endocrine related myopathies.