Hypertensive emergency and hypertensive crisis

Definition

A hypertensive emergency is severe hypertension (according to the German NVL Hypertension above 180 mmHg systolic or above 110 mmHg diastolic, according to the US definition systolic 180 mmHg or higher and/or diastolic 120 mmHg or higher) with signs of acute damage to target organs, mainly the brain, cardiovascular system and kidneys. In hypertensive urgency (hypertensive crisis without organ damage), blood pressure is similarly elevated, but acute organ damage is absent (at most grade 1–2 retinopathy).

Classification

Types of organ damage

• hypertensive encephalopathy
• hypertensive retinopathy; the combination with stage III/IV retinopathy (cotton-wool spots, papilledema) is called malignant hypertension
• preeclampsia or eclampsia
• acute left ventricular failure with pulmonary edema
• myocardial ischemia
• acute aortic dissection
• renal failure

Aetiopathogenesis

In hypertensive encephalopathy, cerebral autoregulation fails: normally cerebral vessels constrict as pressure rises, but above a mean arterial pressure of about 160 mmHg (lower in previously normotensive people) they dilate. The high pressure is then transmitted directly to the capillary bed; plasma passes into the brain tissue, causing cerebral edema with papilledema.

The most common cause of hypertensive urgency is anxiety. Crises also occur in secondary forms of hypertension, such as pheochromocytoma. In stroke and intracranial hemorrhage, elevated blood pressure is often a consequence rather than a cause.

Clinical features

• Neurological: rapidly changing deficits such as confusion, transient cortical blindness, hemiparesis or hemisensory loss, seizures; global deficits (confusion, obtundation, coma) suggest encephalopathy, focal deficits with normal mental status suggest stroke
• Cardiovascular: chest pain and dyspnea; jugular venous distention, basal crackles and third heart sound in pulmonary edema; pulse asymmetry between the arms in aortic dissection
• Renal: often asymptomatic; lethargy or nausea in advanced renal failure
• Eyes: severe retinopathy (sclerosis, cotton-wool spots, arteriolar narrowing, hemorrhage, papilledema) almost always in encephalopathy, often in other emergencies

Diagnosis

The diagnosis is based on a systolic blood pressure above 180 mmHg and evidence of organ involvement. Physical examination focuses on the target organs with neurological examination, fundoscopy and cardiovascular examination.

Organ-specific evaluation

• Brain: with neurological findings, head CT to detect hemorrhage, edema or infarction
• Heart: ECG with acute ischemic changes; with chest pain or dyspnea additionally a chest X-ray
• Kidney: electrolytes and creatinine; urinalysis with red blood cells, red cell casts and proteinuria as signs of renal involvement
• Eye: funduscopy (sclerosis, cotton-wool spots, arteriolar narrowing, hemorrhages, papilledema)
• Aorta: pulse difference between the arms as a clue to aortic dissection

Keep learning in the app

Further reading (open access)

1. MSD Manual Professional: Hypertensive Emergencies
2. StatPearls: Hypertensive Crisis
3. Nationale VersorgungsLeitlinie Hypertonie, Langfassung Version 1.0
4. MSD Manual Professional: Hypertensive Retinopathy
5. MSD Manual Professional: Hypertension
6. MSD Manual Professional: Pheochromocytoma

Cross-references