Primary Hyperaldosteronism
Primary hyperaldosteronism (Conn's) is autonomous aldosterone excess causing hypertension ± hypokalaemia — screened by the aldosterone:renin ratio, confirmed biochemically, and crucially lateralised by adrenal vein sampling before deciding surgery versus a mineralocorticoid receptor antagonist.
The big picture
Autonomous aldosterone secretion (from a unilateral adenoma or bilateral adrenal hyperplasia) drives sodium retention and potassium loss, producing hypertension with suppressed renin and sometimes hypokalaemia. It causes disproportionate cardiovascular harm beyond the blood pressure itself.
Screen with ARR, confirm, then LATERALISE with adrenal vein sampling: unilateral → adrenalectomy, bilateral → MR antagonist — do not let CT alone choose the side.
Mechanism pathway
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Symptom sorter
The common presentation.
Diagnostic algorithm
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Treatment ladder
Determine subtype precisely, then cure unilateral disease surgically and control bilateral disease medically.
Procedure chooser
- Laparoscopic adrenalectomy for lateralised unilateral disease (aldosterone-producing adenoma)
Complications
- Cardiovascular and renal damage from aldosterone excess
- Hypokalaemia complications
- Wrong-side adrenalectomy if not lateralised
- MR antagonist side effects (hyperkalaemia, gynaecomastia)
- Always lateralise with adrenal vein sampling before surgery
- Monitor potassium on MR antagonists
- Switch to medical therapy if bilateral; adjust MR antagonist; manage potassium
Follow-up
- Blood pressure and potassium
- Biochemical cure after surgery (aldosterone/renin)
- Renal function on MR antagonists
- Reassess after adrenalectomy; ongoing monitoring on medical therapy
- Improved/cured hypertension and normalised potassium
- Persistent hypertension/hypokalaemia (wrong side operated or bilateral disease)
- Generally not for monitoring; biochemistry guides
- Persistent hypertension despite cure of aldosteronism; MR antagonist side effects (e.g. gynaecomastia with spironolactone)
Red flags
Screen for primary hyperaldosteronism with the aldosterone:renin ratio.
Risk of operating on the wrong side — lateralise with adrenal vein sampling first.
Treat urgently; investigate the cause.
Summary tables
Subtype → treatment
| Subtype | How identified | Treatment |
|---|---|---|
| Unilateral adenoma | Lateralises on adrenal vein sampling | Laparoscopic adrenalectomy |
| Bilateral hyperplasia | No lateralisation on AVS | MR antagonist (spironolactone/eplerenone) |
Memory hooks
Hypertension + low potassium + suppressed renin = Conn's.
Screen with the aldosterone:renin ratio.
Adrenal vein sampling picks the side, not CT.
Unilateral → adrenalectomy; bilateral → spironolactone/eplerenone.
Board traps
Wrong-side adrenalectomy because CT, not AVS, chose the side.
Missed diagnosis in a normokalaemic resistant hypertensive.
High renin (renal artery stenosis) mislabelled as primary hyperaldosteronism.
Clinical cases
A 48-year-old with resistant hypertension and hypokalaemia has a raised aldosterone:renin ratio confirmed on testing. CT shows a 1 cm left adrenal nodule; the right gland looks normal.
What must be done before recommending left adrenalectomy?