Conn's syndrome (primary hyperaldosteronism)

How it presents

Hypertension that is resistant to standard medication, or occurs alongside low potassium, is the typical flag. Many patients have no specific symptoms and are diagnosed through routine blood pressure investigation.

How it is diagnosed

• Aldosterone-to-renin ratio (ARR) is the screening test. Medication washouts may be required for accurate interpretation.
• Confirmatory testing - salt loading, saline infusion or captopril suppression - depending on local protocol.
• Cross-sectional imaging (usually dedicated adrenal CT) to look for an adenoma.
• Adrenal vein sampling (AVS) is often needed to confirm that aldosterone excess is truly unilateral before recommending surgery. Bilateral hyperplasia is managed medically with a mineralocorticoid receptor antagonist, not surgery.

When surgery is considered

Unilateral adrenalectomy is offered when AVS confirms that one gland is the dominant source. The goals are biochemical cure of aldosterone excess and improvement (sometimes resolution) of hypertension.⁹

How the operation is done

Minimally invasive adrenalectomy (robotic or laparoscopic) is the standard approach for a unilateral aldosterone-producing adenoma. See robotic adrenalectomy. Blood pressure and potassium should be well controlled before surgery, usually with an aldosterone antagonist.

After surgery

Most patients see normalisation of aldosterone and potassium, with improvement in blood pressure control. Some patients remain on one or more antihypertensives but typically at lower doses. Regular review is advised in the first year.⁹