Endocrine Abstracts

Introduction: Cushing’s syndrome (CS) is a rare disease resulting from prolonged exposure to supraphysiological levels of glucocorticoids. Cushing’s Disease is the most frequent cause of endogenous CS. This disease has a broad spectrum of clinical manifestations and is associated with an increased morbi-mortality. Diabetes Mellitus (DM) and hypokalemic alkalosis affects up to 50 and 10% of CS patients respectively. Disease onset and severity reflects the magnitude of cortisol excess, being ectopic ACTH production is the most frequent cause of acute, severe CS. Cushing disease tends to have a slower onset with gradual appearance of the typical phenotype and associated metabolic consequences.

Case report: A 62 year old male with a known medical history of obesity and hypertension was admitted to the emergency department with altered mental status, hyperglycemia and hypokalemia. Physical examination was remarkable for obesity, moon face, facial plethora and proximal muscle weakness. At admission: plasma glucose was 452 mg/dl serum potassium 2.7 mmol/l and arterial pH 7.6. Excessive iv fluids led to congestive heart failure that was treated with standard doses of furosemide. Diuretics were soon stopped due to severe refractory hypokalemia (1.7 mmol/l) that after correction required maintenance iv potassium chloride doses of 120 mEq/day. Further laboratory (dexamethasone suppression tests 1 and 8 mg and inferior petrosal sinus sampling) and imaging (pituitary macroadenoma) investigations confirmed Cushing’s Disease. Endoscopic transphenoidal tumor excision led to disease remission. Currently, 15 months postoperatively, the patient has no complaints, is normokalemic (without potassium supplements) and normoglycemic on metformin monotherapy.

Conclusion: The case is noteworthy for the atypical clinical presentation, severity of the hypokalemia and excellent treatment outcome. The authors emphasize the importance of high clinical suspicion for secondary causes of DM when investigating patients with new onset diabetes, as diagnosing and treating the underlying cause may render the diabetes and its complications potentially curable and preventable respectively.