Secondary hypertension refers to high blood pressure caused by an identifiable underlying condition. Unlike essential (primary) hypertension, these cases may be curable if the cause is treated. Although less common (≈5–10% of cases), recognising clues is important because delayed diagnosis can lead to preventable complications.

📌 When to Suspect / Screen

🧑‍⚕️ Young onset: Age <40 years, or sudden worsening of BP control.
💊 Resistant hypertension: Persistent BP despite ≥3 antihypertensive agents (including a diuretic).
👁️ Severe hypertension: BP >180/110 mmHg, especially with papilloedema or retinal haemorrhage.
🧠 Early complications: Stroke, MI, or heart failure occurring before age 50.
📉 Other clues: Hypokalaemia, abnormal renal function, paroxysmal symptoms (headache, sweating, palpitations).

🩺 Secondary Causes of Hypertension

Cause	Clues	Key Tests & Management
🩸 Renal Artery Stenosis	Resistant HTN, abdominal bruit, ↑ creatinine after ACEi/ARB	Doppler US, CT/MR angiography → Angioplasty ± stent, avoid ACEi/ARB if bilateral
⚡ Primary Aldosteronism (Conn’s)	HTN + hypokalaemia, weakness, cramps	Aldosterone:renin ratio, adrenal CT → Spironolactone/eplerenone, adrenalectomy if unilateral
🔥 Phaeochromocytoma	Paroxysmal HTN, headache, palpitations, sweating	Plasma/urinary metanephrines, MRI/CT → Alpha-blockade → β-blocker → surgery
🌙 Cushing’s Syndrome	Central obesity, moon face, striae, proximal weakness	24h urinary cortisol, dex suppression test → Surgery; ± ketoconazole/metyrapone
🫀 Coarctation of the Aorta	HTN in arms, weak femoral pulses, rib notching	Echo, CT/MR angiography → Surgical repair or balloon angioplasty
🦋 Thyroid Disease	Hyper: tachy, weight loss; Hypo: brady, weight gain	TFTs ± US → Hyper: carbimazole/RAI/surgery; Hypo: levothyroxine; β-blockers for symptoms
😴 Obstructive Sleep Apnoea	Loud snoring, daytime sleepiness, witnessed apnoeas	Polysomnography → CPAP, weight loss, avoid alcohol/sedatives, surgery if refractory

💡 Teaching Pearl

Secondary hypertension is rare but potentially curable. In UK practice, NICE recommends investigation when there are clinical clues (young age, resistant HTN, hypokalaemia, or suggestive symptoms). Always confirm diagnosis with appropriate tests before committing to invasive treatment.

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Secondary Hypertension

📖 Introduction

📌 When to Suspect / Screen

🩺 Secondary Causes of Hypertension

💡 Teaching Pearl

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