Secondary Hypertension Workup

Investigate for secondary HTN if: • Age <40 with HTN. • Resistant HTN (≥3 drugs at maximum tolerated, including diuretic). • Sudden onset / worsening of previously controlled HTN. • HTN + hypokalaemia (suggests primary aldosteronism or Cushing's). • HTN + episodic features (palpitations, sweating, headache → phaeo). • HTN + Cushingoid features. • HTN + abdominal bruit (renal artery stenosis). • HTN in pregnancy / planning pregnancy. • Family history of secondary HTN.