Secondary Hypertension Causes

Expansion

RENAL covers the main groups:

• R - Renal disease, much the commonest secondary cause: chronic kidney disease, polycystic kidney disease, renal artery stenosis
• E - Endocrine: Conn’s syndrome (primary hyperaldosteronism), Cushing’s, phaeochromocytoma, acromegaly, thyroid disease, hyperparathyroidism
• N - Narrowed aorta: coarctation
• A - Apnoea: obstructive sleep apnoea
• L - Loaded with drugs: combined oral contraceptive, steroids, NSAIDs, ciclosporin, venlafaxine, cocaine, liquorice, and sympathomimetics

When to investigate

• Age under 40
• Resistant hypertension, uncontrolled on three drugs including a diuretic
• Hypokalaemia without a diuretic, which suggests Conn’s
• Episodic headache, sweating and palpitations, suggesting phaeochromocytoma
• Radiofemoral delay or a difference between arm and leg pressures, suggesting coarctation
• Abrupt onset or sudden worsening
• Bruit over the abdomen, suggesting renal artery stenosis

Primary hyperaldosteronism is the commonest endocrine cause, and is far more common than was once thought, accounting for perhaps 5 to 10 per cent of hypertension. Screen with the aldosterone to renin ratio.

A rise in creatinine of more than 30 per cent on starting an ACE inhibitor suggests bilateral renal artery stenosis.