Endocrine Abstracts

Objective: We highlight a case of lung cancer presenting with a combination of Ectopic ACTH, SIADH and Nephrotic syndrome where paraneoplastic manifestations are the only presentation of an underlying lung cancer.

Case report: Seventy year male, ex- smoker, hypertensive on Amlodipine, Irbesartan. Presented with 5-week history of leg swelling, reduced appetite.

Examination showed pitting edema of the legs but no signs of cardiac, liver and renal failure.

Investgations: Sodium 126 mmol/l, potassium 2.0 mmol/l, albumin 26 g/l, bicarbonate 36 mmol/l, plasma osmolality 275 mOsmol/kg & normal urea and creatinine.

A 24 h urine collection revealed urinary sodium of 81 mmol/l, chloride 95 mmol/l, potassium, 13 mmol/l, urea 32.7 mmol/l and osmolality of 231 mOsmol/kg, cortisol 1200 nmol/l. &24-hour urine protein 6.48 g/d.

Serum cortisol level >1675 nmol/l, plasma ACTH 303 ng/l (<46). Low dose, high dose dexamethasone suppression test failed to suppress the serum cortisol, (>1639 nmol/l).

Chest X-ray showed a bulky right hilum.

CT chest and abdomen showed a hilar mass of 4.0×4.0 cm with hilar & mediastinal adenopathy and multiple liver metastases. A diagnosis of ectopic ACTH syndrome, SIADH and nephrotic syndrome secondary to metastatic lung cancer presumably small cell carcinoma was made.

He was unfit for chemotherapy and died of pneumonia soon.

Conclusion: This case demonstrates that a search for underlying cancer should be made in patients who present with endocrinal abnormalities. The case also reiterates the need to consider ectopic ACTH in cases of unexplained severe hypokalaemia without typical signs of Cushing syndrome. SIADH in patients with ectopic ACTH syndrome may be under diagnosed due to the antagonistic hormone actions of cortisol and ADH on renal sodium excretion. nephrotic syndrome is the most common paraneoplastic renal abnormality it has never been found in association with ectopic ACTH and SIADH.