Comparison of the clinical features in ectopic ACTH syndrome and Cushing′s disease with hypokalemia / 中华内分泌代谢杂志

ABSTRACT

Objective To study the clinical features of the ectopic ACTH syndrome in order to increase the early diagnostic rate. Methods Clinical features and imaging diagnosis of 8 consecutive patients with ectopic ACTH syndrome were described and laboratory data were compared with those of 16 consecutive patients with ACTH-dependent Cushing′s syndrome accompanied with hypokalemia. Results The ectopic ACTH syndrome occurred in 11.3% of all patients with Cushing′s syndrome and the common causes were lung cancer and bronchial carcinoid. The clinical features of the ectopic ACTH syndrome differ from those of ACTH-dependent Cushing′s syndrome. Ectopic ACTH syndrome occured predominently in men and showed the duration of symptoms less than 5 months and a more rapid clinical course. There were apparent muscle weakness, edema of lower extremities, higher plasma ACTH and free cortisol (F), severe metabolic alkalosis and more negative responses to the high dose of dexamethasone suppression test. Chest X-rays and CT were helpful for tumor localization. The prognosis depended on whether the tumor was malignant or benign, and complete surgical resection of tumor was the key treatment. Conclusion Ectopic ACTH syndrome could be distinguished from the ACTH-dependent Cushing′s syndrome with hypokalemia according to the clinical features, laboratory data, plasm ACTH and F levels, as well as chest X-rays and CT.