UNPREDICTABLE HYPERSECRETION OF CORTISOL IN CUSHINGS-DISEASE - DETECTION BY DAILY SALIVARY CORTISOL MEASUREMENTS

A 70-year-old man with mild signs and symptoms of Cushing's syndrome d ue to an ACTH-secreting pituitary adenoma is described. He had a compl etely unpredictable pattern of urinary excretion of cortisol; 24 h uri ne for determination of cortisol excretion was collected daily at home on 725 consecutive days. During this period there were eight episodes in which urinary cortisol excretion exceeded the upper limit of norma l. Within these episodes the pattern of cortisol secretion was extreme ly unpredictable, with cortisol excretion ranging from normal to highl y elevated. Using a Cluster Analysis Program 61 pulses of cortisol exc retion were detected within the eight periods of cortisol hypersecreti on. The interval between two pulses varied from 2 to 12 days. Between the periods of cortisol hypersecretion, urinary cortisol excretion was completely normal, lasting from 4 to 102 days. There was no differenc e in the clinical expression of Cushing's syndrome between the periods of elevated and normal urinary cortisol excretion. During the last 43 9 days of the observation, cortisol was also measured in saliva collec ted at home at 09.00 after an overnight fast. The salivary cortisol pa ttern closely resembled that of urinary cortisol excretion and there w as a significant correlation between salivary cortisol levels and 24 h urinary cortisol excretion in the 24 h after (r=0.42, p<0.0001, Spear man) and before saliva collection (r=0.44, p<0.0001). On 71% of occasi ons cortisol peaks in saliva, as detected by the Cluster Analysis Prog ram, coincided with urinary cortisol peaks. We conclude that daily mea surement of cortisol in saliva, collected at home, is a convenient and reliable method for detecting intermittent hypercortisolism in patien ts with Cushing's syndrome.