Malignant or Accelerated Hypertension

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Patient Advice

Definition

Malignant or Accelerated Hypertension is a severe form of high blood pressure characterised by sudden and sustained elevations in blood pressure (typically ≥180/120 mmHg) with evidence of damage to organs such as the eyes, kidneys, or brain.

Aetiology

Causes include:

• Primary (Essential) Hypertension: Poorly controlled chronic high blood pressure.
• Secondary Hypertension: Due to underlying conditions like:
  • Renal artery stenosis (narrowing of kidney blood vessels).
  • Glomerulonephritis (kidney inflammation).
  • Phaeochromocytoma (hormone-secreting adrenal tumour).
  • Cushing's syndrome or primary aldosteronism.
• Pregnancy-related Hypertension: E.g., pre-eclampsia or eclampsia.
• Medication-related: E.g., withdrawal of antihypertensive drugs or use of substances like cocaine.

Pathophysiology

The condition involves a vicious cycle of high blood pressure and organ damage:

• Severe Blood Pressure Elevation: Causes damage to small blood vessels (arterioles).
• Endothelial Injury: Leads to leakage of plasma and clot formation.
• Ischaemia: Reduced blood flow to vital organs such as the kidneys, brain, and heart.
• Renin-Angiotensin System Activation: Further elevates blood pressure, worsening the damage.

Risk Factors

Factors increasing the risk include:

• Long-standing, uncontrolled hypertension.
• Chronic kidney disease (CKD).
• Use of recreational drugs (e.g., cocaine, amphetamines).
• Poor adherence to antihypertensive medication.
• Pregnancy-related conditions (e.g., pre-eclampsia).

Signs and Symptoms

Key clinical features are:

• Headache: Often severe and persistent.
• Blurred Vision: Due to swelling in the optic nerve (papilloedema).
• Shortness of Breath: Suggesting fluid overload or heart failure.
• Chest Pain: Indicative of cardiac ischaemia.
• Neurological Symptoms: E.g., confusion, seizures, or weakness, indicating brain involvement.

Investigations

Essential tests include:

• Blood Pressure Measurement: Sustained readings ≥180/120 mmHg.
• Blood Tests:
  • Renal Function Tests: Elevated creatinine and urea levels suggest kidney damage.
  • Electrolytes: Assess for abnormalities, e.g., low potassium in primary aldosteronism.
  • Full Blood Count (FBC): Check for anaemia or haemolysis due to microvascular damage.
• Urine Tests:
  • Dipstick: Proteinuria or haematuria indicates kidney involvement.
  • Albumin:Creatinine Ratio (ACR): Quantifies proteinuria.
• Fundoscopy: Exam of the eyes to detect retinal changes like haemorrhages, exudates, or papilloedema.
• ECG (Electrocardiogram): May show signs of left ventricular strain or ischaemia.
• Chest X-ray: Useful to identify signs of heart failure or pulmonary oedema.

Management

1. Immediate Goals

Lower blood pressure gradually to prevent organ damage while avoiding rapid reductions:

• First-Line Medication: Use intravenous labetalol, or if not available, oral nifedipine for controlled lowering of BP.
• Target Reduction: Lower mean arterial pressure (MAP) by no more than 20-25% within the first hour.

2. Monitoring

• Admit for continuous blood pressure monitoring.
• Monitor for worsening of organ damage using blood tests, urine output, and imaging.

3. Referral to Specialist

Referral to secondary care is essential to manage underlying causes and prevent recurrence. Specialist care may involve:

• Renal biopsy if kidney disease is suspected.
• Endocrine evaluation for hormonal causes such as phaeochromocytoma.
• Long-term antihypertensive therapy tailored to the patient’s needs.

Patient Advice

Key advice includes:

• Adhere strictly to prescribed antihypertensive medication.
• Maintain a low-salt diet and healthy lifestyle.
• Attend regular follow-ups to monitor blood pressure and organ health.
• Seek urgent medical attention if symptoms such as severe headache, chest pain, or vision changes occur again.

References

1. National Institute for Health and Care Excellence (NICE) (2024). Hypertension: Diagnosis and Management. Available at: https://www.nice.org.uk (Accessed: 30 December 2024).
2. British Heart Foundation (BHF) (2024). Hypertension Overview. Available at: https://www.bhf.org.uk (Accessed: 30 December 2024).
3. Wikipedia contributors (n.d.). Hypertensive Emergency. Retrieved from: https://en.wikipedia.org/wiki/Hypertensive_emergency (Accessed: 30 December 2024).