Paediatrics: Mineralocorticoid excess

Mineralocorticoid excess

The principal mineralocorticoid secreted by the adrenal gland is aldoste-rone. Increased production may result from a primary defect of the adre-nal gland (primary hyperaldosteronism) or from factors that activate the renin–angiotensin system (secondary hyperaldosteronism). Hypokalaemia and hypertension are typical features.

Primary hyperaldosteronism

Characterized by hypokalaemia and hypertension. There is suppression of the renin–angiotensin system with low plasma renin levels. Children may have no symptoms, the diagnosis being established after the incidental finding of hypertension. Chronic hypokalaemia may result in muscle weak-ness, fatigue, and poor growth.

Causes of primary hyperaldosteronism

·  Bilateral adrenal hyperplasia

·  Adrenal tumours

·  Glucocorticoid-remediable hyperaldosteronism

Secondary hyperaldosteronism

This occurs when excess aldosterone production is secondary to elevated renin levels. Hypertension may or may not be present.

Causes of secondary hyperaldosteronism

Associated with hypertension

• Renovascular malformations/stenosis

·  Primary hyperreninaemia

·  Juxtaglomerular tumour

·  Wilm’s tumour

·  Post-renal transplantation

·  Urinary tract obstruction

·  Phaeochromocytoma

No hypertension

·  Hepatic cirrhosis

·  Congestive cardiac failure

·  Nephrotic syndrome

·  Bartter’s syndrome

·  Anorexia nervosa

Syndrome of apparent mineralocorticoid excess: type 1 and type 2 variants