Chronic hyponatremia associated with diabetic amyotrophy.

In most diabetic patients, the presence of hyponatremia is usually ascribed to severe hyperglycemia, hypertriglyceridemia, oral hypoglycemic agents, or other drugs. We describe two insulin-treated type II diabetic patients who were seen with severe rapid weight loss, hyponatremia, and diabetic amyotrophy despite good metabolic control. Laboratory evaluation of the hyponatremia suggested the syndrome of inappropriate antidiuretic hormone secretion. Their clinical presentations led to the suspicion of an underlying malignant neoplasm in each case. One patient required demeclocycline for treatment of his symptomatic hyponatremia, while the other improved with fluid restriction and intermittent furosemide therapy. The hyponatremia resolved spontaneously with improvement in body weight and the amyotrophy resolved after four to six months. After 24 to 36 months of close follow-up, no evidence of malignancy has been documented in either of the patients. We conclude that this clinical entity of amyotrophy is benign and should be included in the differential diagnosis of chronic hyponatremia in diabetic patients.