Cushing's disease: establishing the diagnosis and management approach

A 64 year old lady, with a background history of type 2 diabetes mellitus and hypertension, presented with general deterioration of general health, poor glycemic control, difficulty in controlling blood pressure and difficulty in walking. She had past medical history of adenocarcinoma of the oesophagus, treated with surgery and subsequent chemotherapy. General examination revealed high blood glucose and blood pressure and a Cushingoid facies. Overnight dexamethasone suppression test and urinary free cortisol levels confirmed Cushing's syndrome and High dose dexamethasone suppression test showed partial suppression. CT scan of the abdomen showed bilateral hyperplasia of the adrenals with nodularity on the left side, raising the possibility of an adrenal adenoma. ACTH levels were elevated thereby ruling out autonomously functioning adrenal nodule, however increasing the possibility of ectopic ACTH secretion due to the previous medical history. MRI of the pituitary confirmed the presence of an adenoma, thereby pointing to the diagnosis of pituitary dependant Cushing's disease. The patient could not undergo further invasive investigation or surgery due to septicaemia. Medical management of Cushing's syndrome was resorted to in the interim with Ketoconazole, showing excellent response. This case depicts the need for a high index of suspicion for the diagnosis, the importance of organizing specific investigations in the appropriate order to arrive at a diagnosis and an effective management plan.