Diagnosis of Cushing’s syndrome Reevaluation of

Authors: R Görges G Knappe H Gerl M Ventz F Stahl

Publish Date: 2014/03/11

Volume: 22, Issue: 4, Pages: 241-249

PDF Link

Abstract

We studied plasma cortisol levels at 0000 h and 0800 h in 103 patients with Cushing’s syndrome and 144 patients in whom this diagnosis had been excluded These patients were hospitalized in our department from 1975 to 1996 Additionally we measured these parameters in 20 healthy volunteers and in 5 patients with nonendocrine disease Corresponding data of urinary free cortisol and lowdose dexamethasone suppression testing were included in the evaluation Values mean±SD from patients with Cushing’s syndrome 510±232 nmol/l range 165–1488 for plasma cortisol 0000 h 574±242 nmol/l range 236–1612 for plasma cortisol 0800 h 991±885 nmol/24 h range 154–4866 for urinary free cortisol and 479±304 nmol/l range 34–1393 for plasma cortisol after 15 mg dexamethasone Values from the patients excluded from Cushing’s syndrome 99±76 nmol/l range 5–371 for plasma cortisol 0000 h 393±136 nmol/l range 119–812 for plasma cortisol 0800 h 126±84 nmol/24 h range 30–485 for urinary free cortisol and 64±82 nmol/l range 5–395 for plasma cortisol after 15 mg dexamethasone Values of the healthy volunteers respectively patients with nonendocrine disease 59±30 nmol/l range 25–130 respectively 127±80 nmol/l range 62–265 for plasma cortisol 0000 h and 388±144 nmol/l range 157–651 respectively 498±113 nmol/l range 302–581 for plasma cortisol 0800 h None of the Cushing patients exhibited a 0000 h plasma cortisol below 140 nmol/l and only one had a urinary free cortisol below 200 nmol/24 h whereas 4 were complete dexamethasone suppressors The diagnostic value of these parameters was examined based on various cutoffs We recommend determination of midnight plasma cortisol as an efficient and simple additional procedure for the diagnosis of Cushing’s syndrome The sensitivity and specificity of this procedure is similar to urinary free cortisol and slightly above the lowdose dexamethasone suppression testing in our hospitalized patients

Keywords: