artigo original Síndrome de Cushing Endógena: Características Clínico- Laboratoriais em 73 Casos

ABSTRACT Endogenous Cushing’s Syndrome: Clinical and Laboratorial Featuresin 73 Cases.We studied clinical and laboratorial features of 73 patients with endogenousCushing’s syndrome, subdivided as follows: 46 (63%) with Cushing’s disease(CD), 21 (28.7%) with an adrenal tumor and 6 (8.2%) with ectopic ACTH secre-tion (EAS). The rate of typical manifestations of hypercortisolism was similarregardless its etiology. In 100% of cases of Cushing’s syndrome we observedserum cortisol levels greater than 1.8 µg/dL in low-dose dexamethasone (DMS)suppression tests, as well as elevation of serum or salivary midnight cortisol.However, urinary free cortisol was normal in 11.5% of patients. ACTH levelswere suppressed in patients with adrenal tumors, normal or high in CD andalways high in EAS. In the 8-mg overnight DMS suppression test, serum corti-sol suppression > 50% was observed in 78.2% of cases of CD and in 33.3% ofsubjects with EAS, while an 80% suppression was only seen in CD. After stim-ulation with CRH or DDAVP an ACTH increase ≥35% occurred in 81% of indi-viduals with CD and 16.6% of those with EAS, while an ACTH increase ≥50achieved 100% specificity. Moreover, the combination of serum cortisol sup-pression > 50% and an ACTH increase ≥35% in both tests only occurred inCushing’s disease. Pituitary magnetic resonance imaging identified 100% ofmacroadenomas and 59.4% of microadenomas in patients with CD. Among 10patients that underwent bilateral inferior petrosal sinus sampling, a central-to-peripheral ACTH gradient ≥3 after CRH or DDAVP had 90% sensitivity and100% specificity for Cushing’s disease. (Arq Bras Endocrinol Metab2007;51/4:566-574)Keywords: Cushing’s syndrome; Hypercortisolism; Cushing’s disease, Cortisol