Endocrine Abstracts

Introduction: Cushing’s syndrome is broadly categorized into ACTH dependent (pituitary and ectopic source) and ACTH independent (adrenal source). Localizing source of Cushing’s can sometimes be a cumbersome diagnostic process.

Case history: A 25-year-old male patient presented with sudden rapid onset weight gain, muscle weakness and occasional headaches.as well as severe dyspnoea, orthopnea and PND. There was no significant past medical or family history. He was not on any regular medication and denied exogenous steroids intake. He had clinical features consistent with florid Cushing’s syndrome and congestive cardiac failure. Cardiac MRI suggested severe dilated Cardiomyopathy with EF 23% which was treated medically. His screening investigations for Cushing’s showed discordance with clinical picture. He had high 02400 h urine free cortisol on two occasions but suppressed <28 on low dose dexamethasone suppression test. Two early mornings ACTH levels were undetectable and prompted investigations to find an adrenal source. CT as well as MRI adrenals failed to localize an adenoma. Alternative sources were then explored. Pituitary MRI and subsequent dynamic pituitary MRI were entirely normal apart from stalk deviation to left side. No ectopic source of disease was found on Gallium octreotide PET–CT. Rest of the Pituitary function tests were satisfactory. He had Inferior petrosal sinus sampling which showed strong lateralization to left side of pituitary. He is currently awaiting pituitary surgery for Cushing’s disease and has been started on blockade therapy with Metyrapone in the interim. Repeat cardiac MRI shows improvement in cardiac function (EF 41%).

Conclusions: Diagnosing Cushing’s syndrome and identifying the source can sometimes be challenging and require more invasive investigations. We highlight importance of taking clinical picture into account whenever dealing with complicated Cushing’s patients and their discrepant investigations.