5th April 2024

Hyperaldosteronism

Background

Hyperaldosteronism can be defined as excess levels of aldosterone in the blood, causing hypertension and hypokalaemia. Other symptoms commonly seen in patients with hyperaldosteronism include polyuria, lethargy and difficulty concentrating.  Most cases of hyperaldosteronism are primarily due to excess aldosterone being secreted from the adrenal gland. 70% of cases of primary hyperaldosteronism (PA) are caused by bilateral adrenal hyperplasia while 30% are due to aldosterone producing tumours within the adrenal gland (Conn’s syndrome).

Secondary hyperaldosteronism is much rarer and is caused by reduced renal perfusion e.g., renal artery stenosis. The decreased perfusion causes raised renin levels and subsequently raised aldosterone levels. Secondary hyperaldosteronism, therefore, indirectly leads to raised aldosterone levels. Management is based around treating the underlying cause.

Approximately 5% of cases of hypertension are caused by hyperaldosteronism and, therefore, newly hypertensive patients with risk factors or signs suggestive of hyperaldosteronism e.g., being relatively young, should be screened for PA.

Diagnosis and management

Checking the aldosterone/renin ratio is the main screening tool and is raised in patients with PA.

Management depends on the cause. Bilateral adrenal hyperplasia is managed medically with selective aldosterone antagonists, e.g., spironolactone. Conn’s syndrome is definitively treated with an adrenalectomy of the affected gland with four weeks of medical treatment prior to surgery.

References

• Hyperaldosteronism. Oxford Clinical Handbook 9ᵗʰ edition
• Primary hyperaldosteronism. BMJ Best Practice