Hypertension: elevated blood pressure (BP), usually defined as BP >140/90; pathological both in isolation and in association with other cardiovascular risk factors
Severe hypertension: systolic BP (SBP) >200 mmHg and/or diastolic BP (DBP) >120 mmHg
Hypertensive urgency: severe hypertension with no evidence of acute end organ damage
Hypertensive emergency: severe hypertension with evidence of acute end organ damage
Malignant/accelerated hypertension: a hypertensive emergency involving retinal vascular damage
Causes of hypertensive emergency
Usually inadequate treatment and/or poor compliance in known hypertension, the causes of which include:
Essential hypertension
Age
Family history
Salt
Alcohol
Caffeine
Smoking
Obesity
Secondary hypertension
Renal
Renal artery stenosis
Glomerulonephritis
Chonic pyelonephritis
Polycystic kidney disease
Endocrine
Cushing’s syndrome
Conn’s syndrome
Acromegaly
Hyperthyroidism
Phaeochromocytoma
Arterial
Coarctation of the aorta
Drugs
Alcohol
Cocaine
Amphetamines
Pregnancy
Pre-eclamplsia
Pathophysiology of hypertensive emergency
Abrupt rise in systemic vascular resistance
Failure of normal autoregulatory mechanisms
Fibrinoid necrosis of arterioles
Damage to red blood cells from fibrin deposits causing microangiopathic haemolytic anaemia
Microscopic haemorrhage
Macroscopic haemorrhage
Clinical features of hypertensive emergency
Hypertensive encephalopathy
Headache
Visual disturbance
Nausea & vomiting
Confusion
Seizures
Drowsiness
Coma
Hypertensive retinopathy
Visual disturbance
Silver wiring
Cotton wool spots
Flame haemorrhages
Papilloedema
Hypertensive cardiomyopathy
Ischaemic chest pain
Dyspnoea
Bibasal crepitations
Raised jugular venous pressure (JVP)
Hypertensive nephropathy
Oliguria
Intracerebral haemorrhage
Drowsiness
Coma
Focal neurological signs
Aortic dissection
Tearing chest pain radiating to the back
Differential in pulse and BP between right and left upper limbs
Eclampsia
Seizures in late pregnancy
Initial investigation of hypertensive emergency
CT head
Exclude intracranial pathology that may cause, complicate or masquerade as hypertensive emergency
Fundoscopy
Silver wiring
Cotton wool spots
Flame haemorrhages
Papilloedema
12-lead ECG
Left ventricular hypertrophy (LVH)
S wave in V1 or V2 + R wave in V5 or V6 >35 mm
Ischaemic changes
ST depression and/or T wave inversion
Urinalysis
Proteinuria
Haematuria
Beta human chorionic gonadotropin (hCG)
Urea & electrolytes
Acute kidney injury (AKI)
Chest radiograph (CXR)
Pulmonary oedema
Widened mediastinum
Further investigation of hypertensive emergency
Ambulatory BP monitoring in patients not known to have hypertension who present with hypertensive urgency
Exclude secondary causes if not already done so
Initial management of hypertensive emergency
Assess the patient from an ABCDE perspective
Maintain a patent airway: use manoeuvres, adjuncts, supraglottic or definitive airways as indicated and suction any sputum or secretions
Deliver high flow oxygen 15L/min via reservoir mask and titrate to achieve oxygen saturations (SpO2) 94-98% or 88-92% if known to have COPD
Attach monitoring
Pulse oximetry
Non-invasive blood pressure
Three-lead cardiac monitoring
Request 12 lead ECG and portable CXR
Obtain intravenous (IV) access and take bloods
Obtain a CT head to exclude intracranial pathology that may cause, complicate or masquerade as hypertensive emergency
Controlled BP reduction; rapid BP reduction should be avoided because this may compromise blood flow to tissues in which autoregulatory mechanisms are already impared; pharmacological options are:
Nitroprusside IV
Labetalol IV
Nitrates IV
Referral to high dependency unit (HDU) for:
Invasive BP monitoring, cardiac monitoring, urine output monitoring, neurological observations
Hypertensive urgency (asymptomatic)
In asymptomatic severe hypertension, treatment depends on the overall risk of persisting hypertension, the duration of hypertension and the risk of cerebrovascular or myocardial ischaemia with rapid reduction in blood pressure.
Provided there is no imminent risk of neuro- or cardiovascular event, there is no proven benefit from rapid reduction of blood pressure in patients with asymptomatic hypertension. Most such patients who present in the ambulatory setting can therefore be managed as outpatients.
Managing risk factors and ensuring good medication adherence or starting first line hypertensives e.g. amlodipine 5 mg orally, with next day outpatient follow up may be adequate.
Further management of hypertensive emergency
Advise lifestyle changes
Reduce intake of salt, alcohol and caffeine
Health diet
Regular exercise
Smoking cessation
Control other cardiovascular risk factors e.g. diabetes mellitus
Review of antihypertensive medication
If age <55 years: angiotensin converting enzyme inhibitor (A) +/- calcium channel blocker (C)/thiazide diuretic (D) +/- D/C
If age >55 years or black patient: C/D +/- A +/- D/C, respectively
