Persistent elevation of BP in the systemic arterial circulation to a level higher than expected for the age, sex, and race of the individual

Aetiology

Primary hypertension

• Primary hypertension is hypertension with no singular identifiable cause - accounts for up to 90% of patients
• Risk factors:
  • ↑ age (main driver)
  • Smoking
  • Genetics/family history
  • Obesity, OSA
  • ↑ alcohol intake
  • ↑ salt intake

Secondary hypertension

• Secondary hypertension is caused by an identifiable singular cause, removal or reversal of which leads to normalization of BP
• Causes include:
  • Renal disease (most commonly)
  • Endocrine - adrenal gland hyperfunction/tumours, aldosteronism, Cushing’s, pheochromocytoma
  • Coarction of the aorta
  • Drugs e.g. corticosteroids
  • Pregnancy associated hypertension - pre-eclampsia, eclampsia

Pathophysiology

Subtypes of hypertension

Benign hypertension

• Stable elevation of BP over many years
• Asymptomatic, incidental finding often in health checks
• Consequences - LV hypertrophy, congestive cardiac failure, ↑ atheroma, thickening of tunica media, ↑ aneurysm rupture, renal disease

Malignant hypertension

• Acute, severe elevation of BP - diastolic pressure >130-140 mmHg
• Can develop from benign primary or secondary hypertension, or arise de novo
• Needs urgent treatment to prevent death - cerebral oedema, acute renal and heart failure, haemorrhage

White coat hypertension

• Hypertension that only exists when BP is measured during medical consultations