Endocrine Abstracts

Background: Cushing syndrome is caused by chronic, autonomous excess cortisol and causes a wide range of clinical manifestations. Impaired glucose metabolism which often leads to diabetes is a common complication of long-term exposure to both exogenous and endogenous glucocorticoid and plays a vital role in contributing to morbidity and mortality in patients with Cushing syndrome. The prevalence of diabetes in Cushing syndrome varies between 20 and 50% and the overall prevalence of impaired glucose metabolism reaches nearly 70%. We present a case of Adrenal Cushing Syndrome which initially presented as newly diagnosed diabetes.

Case presentation: A 48-year-old woman was referred to the Diabetes clinic in Hong Kong with new diabetes and paraesthesia in her hands. Further tests suggested adrenal Cushing (ACTH undetectable, 24-hour UFC 583 nmol/l (11.9-485), ODST 516 nmol/l (<50 nmol/l)). On returning to the UK, she was referred to the Endocrinology clinic for further evaluation. She was found to have Cushingoid features including thin skin, easy bruising, and facial plethora. Repeat biochemistry strongly supported the diagnosis of adrenal Cushing-(ODST cortisol 561 nmol/l (<50 nmol/l), 24-hour UFC 701, and ACTH 5 ng/l (0 - 46)). CT Abdomen showed a left adrenal adenoma. Repeat HbA1c was 47 mmol/mol with a fasting plasma glucose 6 mmol/l, therefore she was advised to continue with lifestyle adjustment. She subsequently had laparoscopic adrenalectomy (Weiss score 0/5, KI 67 2%) with postoperative good glycaemic control (HbA1c 40).

Conclusion: This case highlights the common association between Cushing syndrome and impaired glucose metabolism and diabetes. Early diagnosis and treatment of diabetes can reduce overall cardiovascular morbidity and mortality in patient with Cushing syndrome. Although fasting blood glucose and HbA1c may be normal in some patients, they may still have post prandial hyperglycaemia. Therefore, an OGTT should be considered in all patients with Cushing syndrome to identify glucose metabolism abnormalities.