Shy-Drager syndrome with abnormal circadian rhythm of plasma antidiuretic hormone secretion and urinary excretion.

A 67-year-old patient with Shy-Drager syndrome (SDS), exhibited nocturnal polyuria associated with abnormal circadian rhythm of antidiuretic hormone (ADH) secretion and nocturnal polyuria. The patient excreted a larger volume of urine during the nighttime compared to that in the daytime. The specific gravity of urine at night was lower than that during the day. In contrast to normal circadian rhythm of ADH, the patient's plasma concentration of ADH was increased in the daytime. The present study raised the possibility that an altered circadian rhythm of plasma ADH secretion might be considered a result of the neurodegenerative changes involving the hypothalamus.