Myopathy, Endocrine

Myopathies are associated with a number of different endocrinopathies related to thyroid, parathyroid, adrenal, and pituitary dysfunction. These 'endocrine myopathies' are typically characterized by the insidious onset of proximal muscle weakness, and recovery generally occurs with treatment of the underlying hormonal abnormality. In most instances, the myopathy associated with endocrine disease is a minor component of the clinical disorder; however, occasionally, as in patients with a thyrotoxic myopathy, the neuromuscular manifestations may be the presenting feature of the endocrinopathy. Endocrine myopathies should be considered in the differential diagnosis of a patient with symptoms of fatigue, myalgia, cramps, or weakness. They should also be considered in patients presenting with worsening symptoms from a preexisting neuromuscular condition or in patients responding poorly to treatment.