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Hypertensive emergency


Definitions surrounding hypertensive emergency

  • 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



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