Overview
Classification
Hypertension is defined as persistently elevated blood pressure, based on at least two readings over at least two visits.- Normal <120 / 80
- Pre-hypertension 120 / 80 - 139 / 89
- Stage I hypertension 140 / 90 - 159 / 99
- Stage II hypertension >160 / 100
Pathogenesis
Causes of Hypertension
Primary
- Primary (essential) hypertension: chronically elevated blood pressure of unknown aetiology (the most common cause of hypertension in the community)
Secondary
- Chronic kidney disease
- Renovascular - fibromuscular dysplasia, atherosclerosis
- Endocrine - hyperthyroidism, hypothyroidism, Cushing's syndrome, primary aldosteronism, phaeochromocytoma, hyperparathyroidism
- Drugs - NSAIDs, amphetamines, glucocorticoids, fludrocortisone, erythropoietin, VEGF inhibitors, calcineurin inhibitors
- Aortic coarctation
- Obstructive sleep apnoea
Factitious
- White coat hypertension: falsely elevated blood pressure may occur due to by anxiety in a healthcare setting, recent exercise or recent caffeine intake.
- Recent exercise or caffeine intake
Manifestations
Complications of Hypertension
- Cardiovascular - left ventricular hypertrophy, heart failure, ischaemic heart disease, peripheral vascular disease, arrhythmia
- Cerebrovascular - ischaemic stroke, haemorrhagic stroke, posterior reversible encephalopathy syndrome
- Hypertensive retinopathy
- Hypertensive nephropathy
- Erectile dysfunction
Management
Management Options
Non-Pharmacologic
- Diet - low in salt
- Exercise - increase incidental exercise and reduce sedentary time
- Smoking cessation
- Alcohol reduction
Pharmacologic
- ACE inhibitors (ACEi) - captopril, ramipril, perindopril
- Angiotensin II receptor blockers (ARBs) - candesartan, irbesartan
- Calcium channel blockers (CCBs) - amlodipine
- Thiazides - hydrochlorothiazide
- Aldosterone antagonists - spironolactone
- Alpha blockers - prazosin
Common Blood Pressure Targets
- Most patients: <140/90
- Diabetics: <130/80
Pearls
- Set realistic targets
- Use non-pharmacologic and pharmacologic strategies
- Titrate medications to the patient's blood pressure and side effects, e.g. electrolytes / renal function (ACEi / ARBs), cough (ACEi), oedema (CCBs)
- Titrate up to the maximum dose of an antihypertensive before adding an additional medication
- If the patient's blood pressure is not responding: consider white coat hypertension, non-adherence or secondary causes
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