Endocrine Abstracts

A 59 year old man was admitted with epistaxis. Blood pressure on admission was 213/110 mmHg. Past medical history included hypertension (3 years) and a cerebrovascular accident 5 years previously. Drug therapy included an ACE inhibitor, beta-blocker and thiazide diuretic. He denied thirst, polyuria or weight loss. He was an ex-smoker. On examination he was not Cushingoid. There were no diabetic complications.

On block analysis potassium was 2.2mmol/l and plasma glucose 15.7mmol/l. Liver and renal function were normal but CO2 was raised at 37mmol/l. Chest XR showed segmental collapse in the right upper lobe. Despite cessation of the thiazide diuretic he required high dose potassium supplements to prevent recurrent hypokalaemia. We suspected hyperaldosteronism but doppler studies of the renal arteries were normal as was a supine renin activity at 0.30ng/ml/h and aldosterone at 493pmol/l. With the addition of an alpha blocker and a calcium antagonist his blood pressure came under good control. Despite maximum doses of metformin and gliclazide, glycaemic control remained poor, meriting the addition of insulin (glargine).

He had an episode of decreased consciousness and a MRI of brain showed a ring enhancing mass lesion in the right cerebellar hemisphere in keeping with a metastasis. CT scan of chest and abdomen demonstrated a 2-3cm soft tissue mass in the right upper lobe with extensive lymphadenopathy and liver metastases. A random serum cortisol was 3665nmol/l, ACTH 448ng/l and 24h urinary free cortisol 24501 nmol/24h and a cortisol:creatinine ratio of 4426. This confirmed the diagnosis of ectopic ACTH syndrome, presumably from a primary lung carcinoma. His condition deteriorated rapidly and he died 22 days after admission. A post mortem was refused. This case illustrates an unusual presentation of ectopic ACTH syndrome which presented a unifying diagnosis and should always be considered in the differential diagnosis of hypertension and hypokalaemia.