Hypertension

Hypertension is a major risk factor for cardiovascular disease, chronic kidney disease, and vascular dementia. It is often asymptomatic ('the silent killer') until complications arise. Diagnosis should not be made on a single clinic reading unless ≥180/120 mmHg (Stage 3). For clinic readings between 140/90 and 179/119 (Stage 1 or 2 potential), ABPM or HBPM is required for confirmation. 95% of cases are 'Essential' (primary), while 5% are secondary to renal or endocrine causes. Management involves lifestyle modifications (weight loss, low salt, reduced alcohol) and pharmacological steps. The NICE 'ACD' algorithm guides therapy: Step 1 depends on age and ethnicity (ACEi/ARB for <55/non-Black; CCB for others). Targets are <140/90 mmHg for those <80 years and <150/90 mmHg for those ≥80. Regular monitoring for end-organ damage (U&Es, Fundoscopy, ECG) is essential.

Blood pressure is the product of cardiac output and total peripheral resistance. Primary hypertension is a polygenic condition influenced by environmental factors (salt intake, obesity). Pathophysiological mechanisms include: 1. Over-activation of the Renin-Angiotensin-Aldosterone System (RAAS), leading to vasoconstriction and sodium retention. 2. Increased sympathetic nervous system activity. 3. Endothelial dysfunction with reduced Nitric Oxide (vaso-dilator) and increased Endothelin (vasoconstrictor). 4. Structural changes in the arterial wall (stiffening). Secondary causes include Renal diseases (Renovascular disease, Glomerulonephritis), Endocrine causes (Conn’s syndrome - primary hyperaldosteronism, Phaeochromocytoma, Cushing’s, Acromegaly), and coarctation of the aorta. Chronic high pressure leads to hyaline arteriolosclerosis and accelerated atherosclerosis.

Hypertension is usually asymptomatic. However, severe hypertension (Stage 3) may cause headaches, visual disturbances, or epistaxis. Clinical signs are usually related to end-organ damage: Hypertensive retinopathy (Silver-wiring, AV nipping, flame haemorrhages, papilloedema), Left Ventricular Hypertrophy (forceful apex beat), and signs of heart failure. Complications include: Haemorrhagic or Ischaemic stroke, Myocardial Infarction, Aortic Dissection, Chronic Kidney Disease, and Hypertensive Encephalopathy. Hypertensive Crisis includes Urgency (≥180/120 without end-organ damage) and Emergency (≥180/120 WITH acute end-organ damage - e.g., pulmonary oedema or encephalopathy).

1. Diagnosis: Clinic BP followed by Ambulatory BP Monitoring (ABPM) or Home BP Monitoring (HBPM).
2. End-organ damage screen: Urine ACR (proteinuria), U&Es (CKD), 12-lead ECG (LVH), Fundoscopy (retinopathy), HbA1c (diabetes screen).
3. Secondary cause screen (if <40 or refractory): Renal ultrasound/Doppler, Plasma Aldosterone/Renin ratio, 24h Urinary Metanephrines.

Treatment criteria: All Stage 2; Stage 1 if <80 with end-organ damage, CVD, Renal disease, Diabetes, or QRISK >10%.
1. Lifestyle: Salt <6g/day, exercise, weight loss, stop smoking.
2. Step 1: ACE inhibitor or ARB (if <55 and not of Black African/Caribbean family origin). Calcium Channel Blocker (CCB, e.g. Amlodipine) if ≥55 or Black African/Caribbean origin.
3. Step 2: ACE/ARB + CCB; or ACE/ARB + Thiazide-like diuretic (e.g. Indapamide).
4. Step 3: ACE/ARB + CCB + Thiazide-like Diuretic.
5. Step 4 (Resistant HTN): Add Low-dose Spironolactone if K+ ≤4.5; Alpha-blocker (Doxazosin) or Beta-blocker if K+ >4.5.