Hypertension (essential or secondary)

Overview

•Hypertension = persistently elevated BP increasing risk of cardiovascular, cerebrovascular, and renal end-organ damage

•Diagnosis must be confirmed with ABPM (preferred) or HBPM - never from a single clinic reading alone

NICE 2023 hypertension classification

Stage	Clinic BP	ABPM/HBPM confirmation
Stage 1	140-159/90-99 mmHg	≥135/85 mmHg (daytime average)
Stage 2	≥160/100 mmHg	≥150/95 mmHg
Severe	≥180/120 mmHg	Same-day assessment for end-organ damage

•White coat hypertension - elevated clinic BP, normal ABPM/HBPM; not benign but no antihypertensive medication required

•Masked hypertension - normal clinic BP, elevated ABPM; carries similar risk to sustained hypertension - easy to miss

Aetiology

•Essential (primary) - ~95% of cases; multifactorial (genetic, RAAS dysregulation, sympathetic activation, salt sensitivity)

•Secondary - ~5%; suspect if resistant to treatment, onset <40 years, severe at presentation, or specific clinical clues

•Renal causes (most common secondary group):

•Renal artery stenosis - renal bruit or worsening renal function on ACE inhibitor; atherosclerotic (older) or fibromuscular dysplasia (young women)

•Chronic kidney disease, polycystic kidney disease

•Endocrine causes:

•Primary hyperaldosteronism (Conn's) - most common endocrine cause; clue: hypokalaemia + low renin + hypertension

•Phaeochromocytoma - episodic hypertension, palpitations, headache, diaphoresis

•Cushing's syndrome - cortisol excess causes sodium retention

•Drug causes: NSAIDs, combined oral contraceptive pill, cocaine/amphetamines, liquorice (glycyrrhizin), MAOIs + tyramine

•Coarctation of the aorta - clue: radio-femoral delay, lower BP in legs than arms

•Obstructive sleep apnoea - clue: resistant hypertension, snoring, daytime somnolence

Presentation

•Typically asymptomatic - detected incidentally ('silent killer')

•Headache - occipital, worse in the morning; only reliably associated with severe hypertension

•Visual disturbance - blurring or loss suggests hypertensive retinopathy or papilloedema

•Chest pain/dyspnoea - suggests hypertensive heart disease, ACS, or heart failure

🚨

Hypertensive emergency (≥180/120 mmHg + end-organ damage: encephalopathy, acute LVF, AKI, retinal haemorrhages/papilloedema, aortic dissection) = admit for IV treatment. Hypertensive urgency (severe BP, no end-organ damage) = urgent oral treatment, not same-day admission.

Investigations

•ABPM - preferred to confirm diagnosis after elevated clinic reading; daytime average ≥135/85 mmHg confirms hypertension

•HBPM - alternative if ABPM not tolerated; two readings 1 minute apart, twice daily, ≥4 days; discard day 1

•Urine dipstick + ACR - proteinuria as marker of renal end-organ damage

•Bloods - U&Es (baseline before ACE inhibitor/ARB; hypokalaemia suggests Conn's), fasting glucose/HbA1c, lipids, eGFR

•12-lead ECG - left ventricular hypertrophy, arrhythmia, ischaemic changes

•Fundoscopy - hypertensive retinopathy (AV nipping, silver wiring, flame haemorrhages, papilloedema in emergency)

•Second-line (targeted): renal ultrasound, 24-hour urinary catecholamines/plasma metanephrines (phaeochromocytoma), aldosterone:renin ratio (Conn's), renal artery Doppler/CT-MR angiography (renovascular disease)

Management

•Lifestyle (all patients): reduce salt <6 g/day, DASH diet, aerobic exercise ≥150 min/week, weight loss (target BMI <25), alcohol ≤14 units/week, smoking cessation

•When to start drug treatment (NICE 2023):

•Stage 1 (ABPM 135-149/85-94): treat if <80 years AND any of - target organ damage, CVD, renal disease, diabetes, or QRISK3 ≥10%; otherwise lifestyle advice + annual review

•Stage 2 (ABPM ≥150/95): treat ALL patients regardless of cardiovascular risk

•Severe (clinic ≥180/120): same-day assessment for end-organ damage; start treatment promptly; review within 7 days if no emergency features

•BP targets (NICE 2023):

•<80 years: clinic <140/90 mmHg (ABPM/HBPM <135/85 mmHg)

•≥80 years: clinic <150/90 mmHg (less aggressive to reduce falls/hypoperfusion risk)

•Type 2 diabetes + CKD with ACR >70 mg/mmol: clinic <130/80 mmHg

⚠️

ACE inhibitors and ARBs must NOT be combined (dual RAAS blockade) - increased risk of hyperkalaemia and AKI without additional BP-lowering benefit. NICE explicitly advises against this combination.

💡

Step 1 in patients of Black African/Caribbean origin: use a calcium channel blocker (e.g. amlodipine) rather than an ACE inhibitor/ARB - as in the vignette of a Black Caribbean woman started on amlodipine 5 mg once daily.

Prognosis

•10 mmHg sustained reduction in systolic BP: ~17% reduction in CVD risk, ~27% reduction in stroke risk, ~28% reduction in heart failure risk

•Secondary hypertension may be curable if the underlying cause is treated (e.g. adrenalectomy for Conn's syndrome)

•Essential hypertension is a lifelong condition requiring long-term monitoring and medication adherence