Hypertensive Emergencies
Definition and clinical significance
A hypertensive emergency is a marked elevation of blood pressure (typically systolic >180 mmHg and/or diastolic >120 mmHg) accompanied by acute or progressive target‑organ damage. High blood pressure alone does not constitute an emergency - the presence of new or worsening end‑organ injury (brain, heart, kidneys, eyes, or large vessels) distinguishes a hypertensive emergency from a hypertensive urgency (NICE NG136).
Key same‑day referral / escalation triggers (NICE NG136) If clinic or ED BP is ≥180/120 mmHg, arrange same‑day specialist assessment when any of the following are present:
- Retinal haemorrhage or papilloedema.
- New confusion.
- Chest pain.
- Signs of heart failure.
- Acute kidney injury.
Pathophysiology
Acute severe hypertension overwhelms vascular autoregulation, causing endothelial injury, capillary leak, oedema and ischaemia. Rapid rises in afterload increase myocardial oxygen demand and shear stress (increasing dissection risk), and impair renal perfusion.
Management aims to limit further organ injury by controlled blood pressure reduction while avoiding precipitous falls that can cause cerebral, renal or coronary ischaemia.
Presentation - look for organ‑specific features
Neurological
- Hypertensive encephalopathy: severe headache, nausea/vomiting, confusion, reduced conscious level, seizures.