SAT-384:
Does a Normal Urine Free Cortisol Result Rule out Cushing’s Syndrome?
Results: Seventy-two patients were diagnosed with CS (aged 18-77 years, 51 females). Of these, 51 had Cushing’s disease (CD), 10 had ectopic CS while 2 had an adrenal source of Cushing’s based on pathology. Biochemical tests including inferior petrosal sinus sampling (IPSS) suggested ectopic CS but no tumor was found (occult) in 6 patients. IPSS was indicative of a pituitary source in 2 patients with failed transsphenoidal surgery while one patient did not complete evaluation for ACTH-dependent CS. UFC results were available in all, 17OHCS in 70, LNSC in 21, midnight serum cortisol in 68 and DST results in 37 patients. UFC was falsely normal in six and only minimally elevated (< 2 x ULN) in 13 patients (normal renal function, no history of cyclicity, all had CD). Of these 19 patients, 24h 17OHCS was abnormal in all, LNSC was abnormal in 12, midnight serum cortisol was abnormal in 18 and DST was abnormal in 12 patients. Hourly 24-hour sampling for cortisol performed in 3 of these patients revealed abnormal nadir (> 7.5 mcg/dL) and mean daily serum cortisol (> 9 mcg/dL) levels.
Conclusion: UFC can be falsely normal or only minimally elevated in mild CS. Multiple collections and use of complimentary screening tests including 24-hour urine 17OHCS and LNSC can help make a diagnosis and prevent delay in treatment.
(1) Newell-Price J, et al. Cushing’s syndrome. Lancet. 2006;367(9522):1605-17. (2) Alexandraki KI, et al. Is urinary free cortisol of value in the diagnosis of Cushing’s syndrome. Curr Opin Endocrinol Diabetes Obes. 2011;18:259–63. (3) Kidambi S, et al. Limitations of nocturnal salivary cortisol and urine free cortisol in the diagnosis of mild Cushing’s syndrome. Eur J Endocrinol. 2007;157(6):725-31
Nothing to Disclose: STS, LKN
Sources of Research Support: This research was in part supported by the intramural research program of NICHD/NIH
Read the entire article at http://press.endocrine.org/doi/abs/10.1210/endo-meetings.2015.ahpaa.9.sat-384
Filed under: adrenal, Clinical trials, Cushing's, pituitary | Tagged: 17-hydroxycorticosteroids, 17OHCS, 24-hour urinary free cortisol, abstract, adrenal, alcoholism, cortisol, Cushing's Syndrome, depression, dexamethasone suppression test, Dr. Lynnette Nieman, increased fluid intake, IPSS, National Institutes of Health, NIH, obesity, Petrosal Sinus Sampling, pituitary, renal insufficiency, salivary, salivary cortisol, stress, UFC, uncontrolled diabetes | Leave a comment »