Other Hypertensive Emergencies

Other hypertensive emergencies include:

Acute renal impairment

Acute renal dysfunction, associated with severe elevations in BP, mandate urgent control of hypertension in order to prevent progression to acute renal failure.

In patients with renal failure, accumulation of the metabolite thiocyanate can produce toxicity over a period of days. Expert advice should be rapidly sought when a hypertensive emergency presents with renal impairment.

Aortic dissection

The main priority in the initial management of aortic dissection associated with elevated BP is prevention of extension of the dissection. Ideally the aim is to reduce systemic vascular resistance by vasodilation without causing a reflex increase in cardiac output.

Intravenous labetalol (with its mixed alpha and beta antagonist properties) is a useful drug in this context. A nitrate infusion can be added if needed or alternatively, a nitrate infusion with a more selective beta-blocker (e.g. atenolol) is suitable.

A further alternative is the combination of nitroprusside with a beta blocker. The goal is to reduce the systolic BP to 110-120 mmHg or lower.


Eclampsia is characterised by convulsions and coma associated with hypertension during pregnancy or soon after delivery. The treatment of this hypertensive emergency involves magnesium sulphate (4g parentally) to control seizures, reduction of blood pressure and immediate obstetric consultation.

Intravenous hydralazine has historically been used for BP control in eclampsia, but more recently intravenous labetalol or nicardipine have been shown to be the agents of choice. Nitroprusside should be avoided in pregnancy because of its potential toxicity to the foetus.


Phaeochromocytomas are catecholamine-secreting tumours predominantly of the adrenal glands. Confirmation of the diagnosis requires demonstration of increased levels of urinary or plasma catecholamines.

Hypertensive emergencies associated with phaeochromocytomas should be treated with predominantly alpha or mixed alpha and beta adrenergic blocking agents: intravenous phentolamine or labetalol are suitable.