Summary
Mineralocorticoid hypertension is most often caused by autonomous overproduction of aldosterone, but excess of other mineralocorticoid precursors can lead to a similar presentation. 11-Deoxycorticosterone (DOC) excess, which can occur in 11-β hydroxylase or 17-α hydroxylase deficiencies, in DOC-producing adrenocortical tumours or in patients taking 11-β hydroxylase inhibitors, may cause mineralocorticoid hypertension. We report a 35-year-old woman who in the third trimester of pregnancy was found to have a large adrenal mass on routine obstetric ultrasound. On referral to our unit, persistent hypertension and long-standing hypokalaemia was noted, despite good compliance with multiple antihypertensives. Ten years earlier, she had hypertension noted in pregnancy which had persisted after delivery. A MRI scan confirmed the presence of a 12 cm adrenal mass and biochemistry revealed high levels of DOC and low/normal renin, aldosterone and dehydroepiandrosterone, with normal catecholamine levels. The patient was treated with antihypertensives until obstetric delivery, following which she underwent an adrenalectomy. Histology confirmed a large adrenal cortical neoplasm of uncertain malignant potential. Postoperatively, blood pressure and serum potassium normalised, and the antihypertensive medication was stopped. Over 10 years of follow-up, she remains asymptomatic with normal DOC measurements. This case should alert clinicians to the possibility of a diagnosis of a DOC-producing adrenal tumours in patients with adrenal nodules and apparent mineralocorticoid hypertension in the presence of low or normal levels of aldosterone. The associated diagnostic and management challenges are discussed.
Learning points:
Hypermineralocorticoidism is characterised by hypertension, volume expansion and hypokalaemic alkalosis and is most commonly due to overproduction of aldosterone. However, excess of other mineralocorticoid products, such as DOC, lead to the same syndrome but with normal or low aldosterone levels.
The differential diagnosis of resistant hypertension with low renin and low/normal aldosterone includes congenital adrenal hyperplasia, syndrome of apparent mineralocorticoid excess, Cushing’s syndrome, Liddle’s syndrome and 11-deoxycorticosterone-producing tumours.
DOC is one intermediate product in the mineralocorticoid synthesis with weaker activity than aldosterone. However, marked DOC excess seen in 11-β hydroxylase or 17-α hydroxylase deficiencies in DOC-producing adrenocortical tumours or in patients taking 11-β hydroxylase inhibitors, may cause mineralocorticoid hypertension.
Excessive production of DOC in adrenocortical tumours has been attributed to reduced activity of the enzymes 11-β hydroxylase and 17-α hydroxylase and increased activity of 21-α hydroxylase.
The diagnosis of DOC-producing adrenal tumours is challenging because of its rarity and poor availability of DOC laboratory assays.
M018 Apparent mineralocorticoid excess syndrome (AMES): 20 year follow-up in four patients