Risks of inappropriate secretion of antidiuretic hormone in multiple system atrophy.

摘要

Multiple system atrophy (MSA) affects the hypothalamus, similar to other neurological diseases. Hypothalamic cells synthesize antidiuretic hormone (ADH), which increases water reuptake in the kidney. Hypothalamic disturbances can lead to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and resultant hyponatremia. ADH levels usually increase in SIADH. However, normal ADH levels are occasionally seen, but they are inappropriate in the presence of abnormally decreased osmolarity (<280 mOsm/kg), a condition thought to suppress physiological ADH secretion. To date, 6 patients with MSA had SIADH (Table I). We describe the first MSA patient with extreme hyponatremia (99 mEq/L) and the highest reported ADH concentration. We also measured ADH in 14 severely disabled patients with MSA, but not symptomatic SIADH.