History: Usually, multiple organ systems are involved and myopathy is only one part of the history, although exceptions do occur and are noted in Pathophysiology. The history of myopathy in general is that of proximal more than distal muscle weakness, with or without associated muscle pain, cramps, and/or spasms. The weakness is typically symmetric or rapidly becomes symmetric. Muscle atrophy may or may not be present. Adrenal dysfunction Hypoadrenalism: In hypoadrenalism, the neurological manifestations of behavioral disturbance and mentation are prominent; myopathy is not a frequent presenting finding. Hyperadrenalism: Cushing syndrome may present with the usual cushingoid features plus pain and weakness. Corticosteroid myopathy is the most common endocrine-related muscle disease. Please refer to the article Cushing Syndrome for details. Thyroid dysfunction: Disorders of thyroid function may result in muscle weakness, and determination of thyroid function remains an integral part of the evaluation for muscle weakness. Hypothyroidism: Muscle weakness occurs most prominently in the adult forms of myxedema. General symptoms include weight gain, neuropathy, fatigue, cold intolerance, sleepiness, and emotional disturbances in addition to muscle stiffness, weakness, and pain. Notably, psychiatric disease may be prominent. Cerebellar ataxia may be seen in adults, less often in children, in whom cerebellar involvement is more midline. Hyperthyroidism: General symptoms include weight loss, sweating, tremor, muscle wasting, and painless weakness. Occasional patients have myalgia, cramps, and bulbar and ocular muscle weakness. Ocular symptoms (diplopia, reduced blinking, lid droop) and skin disease may be present, especially in the case of Graves disease. Parathyroid dysfunction Hypoparathyroidism: Tetany with or without carpopedal spasm is seen. Muscle pain, cramps, and spasms are present in up to one half of patients. Muscle weakness is usually mild. General symptoms include short stature with rounded face, thickened calvarium and other bony abnormalities, and neurological symptoms (eg, seizures, mentation defects). Hyperparathyroidism: Muscle wasting and myopathy (ie, proximal muscle weakness) are common. Other symptoms may include the findings denoted by the well-known phrase "(painful) bones, (renal) stones, (gastrointestinal) groans, and (psychiatric) moans." Notably, depression, mentation defects, memory loss, and mood changes may be present. Also, renal stones are an almost constant feature of this disease syndrome. Pituitary dysfunction: The myopathy from pituitary disease may be a result of secondary adrenal dysfunction or other endocrine disturbance. Hypopituitarism: Often, the myopathy results from secondary adrenal dysfunction. General symptoms include amenorrhea, loss of libido, "alabaster skin," lethargy, constipation, and cold intolerance. Hyperpituitarism: As with hypopituitarism, secondary adrenal effects may be responsible for the myopathy. General symptoms include infertility, impotence, headaches, and mass effects of the pituitary tumor. Physical: Physical examination should focus on the entire body, as the endocrine diseases usually present with multiple system findings. An endocrine tumor is in the differential diagnosis, and signs of a hormone-secreting tumor may be seen on examination. Neck flexor weakness reflects proximal muscle weakness and may be noted in myopathies; dysphagia from bulbar weakness also can occur. Respiratory muscle weakness may occur in endocrine disease (Siafakas et al, 1999). Physical examination findings should correlate with the underlying endocrine disease. However, the following patterns may be observed: In thyrotoxicosis, muscle weakness and atrophy may affect muscles of proximal arms more than those of the legs. Muscle stretch reflexes are usually present (may be depressed) even in weak muscles. Adrenal dysfunction Hypoadrenalism: Examination may show an ataxic gait. Cognition may be poor. Hyperadrenalism: Papilledema and other signs and symptoms of increased intracranial pressure may be present. Thyroid dysfunction Hypothyroidism: Motor movements can have a reduced velocity with delayed relaxation of muscle stretch reflexes. Median neuropathy at the wrist commonly accompanies this diagnosis. Hyperthyroidism: In addition to the findings of Graves disease, muscle weakness with atrophy of the pelvic girdle musculature may be present. Parathyroid dysfunction Hypoparathyroidism: Tetany is a common finding; cataracts may be present. Increased intracranial pressure is not a constant finding, but may be present. Hyperparathyroidism: Myopathy is a prominent finding. Both symmetric weakness of the proximal limbs and atrophy are present. Pituitary dysfunction: The myopathy from pituitary disease may be a result of secondary adrenal dysfunction or other endocrine disturbance. Hypopituitarism: Multiple endocrinopathies may result from pituitary dysfunction. Pituitary tumor may have focal mass effects. Hyperpituitarism: Multiple endocrinopathies may result from pituitary dysfunction. Mass lesions may have local effects.