The localization diagnosis of patients with adrenocorticotropic hormone-dependent Cushing's syndrome in adolescence

Abstract

Objective: To elucidate the clinical characteristics and localization diagnosis of patients with adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS) in adolescence. Methods: The clinical data, laboratory examination and localization diagnosis from 35 patients aged less than 18 years old with adolescent CS who were treated at Peking Union Medical College Hospital between January 1990 and March 2012 were analyzed. Results: There were 29 cases of Cushing's disease (CD) and 6 cases of ectopic ACTH syndrome (EAS). Compared to patients with EAS, those with CD were older at diagnosis[(15.2±2.7) vs (12.8±4.4) years], and had longer disease course[(1.9±1.5) vs (0.7±0.3) years]and higher serum potassium[(3.8±0.6) vs (2.5±0.7) mmol/L], however the plasma ACTH level[(15.4±14.9) vs (42.5±22.7) pmol/L]was lower (all P<0.05). If the cut-off of the ratio of 24-hour urine free cortisol (24 h UFC) after low-dose dexamethasone suppression test (LDDST) to before LDDST was 0.65, the sensibility to diagnose CD was 70.8%, and the specificity was 100%. If the cut-off of the 24 h UFC ratio after high-dose dexamethasone suppression test (HDDST) to before HDDST was 0.54, the sensibility to diagnose CD was 91.7%, and the specificity was 100%. If the cut-off of the plasma ACTH ratio of inferior petrosal vein[bilateral inferior petrosal sinus sampling (BIPSS)]to peripheral vein was 2, only 6 CD patients (6/8) met it. Conclusion: The study suggested that HDDST was more meaningful in the localization diagnosis of patients with ACTH-dependent CS in adolescence.