Hypertensive emergencies

Introduction

A hypertensive crisis is a severe and potentially life threatening increase in blood pressures (BP) which may result in an acute stroke, subarachnoid haemorrhage, seizures (hypertensive encephalopathy), heart attack, acute dissection of aorta, heart failure, renal damage or eclampsia (during pregnancy).
The underlying cause may be primary hypertension; however, secondary causes of hypertension must be excluded. In adult patients this often occurs with a BP > 180/120 mmHg, while in children this may occur at lower BP levels.
These patients need careful examination to exclude target organ damage.
Rapid correction of blood pressure with careful monitoring to avoid a precipitous drop is indicated to prevent organ damage.

Symptoms of hypertensive emergencies

Signs of hypertensive emergencies

The following are the signs of hypertensive emergencies

  1. Severely elevated blood pressure (for age)
  2. Unconsciousness
  3. Seizures
  4. Neck rigidity
  5. Lung crepitations

Investigations

  • Chest X-ray
  • 12-lead ECG
  • FBC
  • Urinalysis
  • Blood urea, electrolytes and creatinine
  • Brain CT scan (for stroke)
  • Chest CT scan with angiography (for suspected aortic dissection)
  • Cardiac enzymes: creatinine kinase-MB (CK-MB), serum aspartate transaminase (AST), serum lactic dehydrogenase (LDH) and troponins (for acute coronary syndrome) Echocardiography

Treatment for hypertensive emergencies

Objectives

The treatment objectives of hypertensive emergencies are:

  1. To limit further organ-related complications by controlled reduction of BP
  2. To control and subsequently prevent seizures if present
  3. To manage identified target organ damage

Non-pharmacological treatment

  • Strict bed rest

Pharmacological treatment

Evidence Rating: [A]
Labetalol, IV,
Adults:

  • 20-50 mg stat. (over a 2 minute period).
  • Repeat at 10 minute intervals, if necessary, to a max. of 200 mg

Children

  •  12-18 years; 10-30 mg stat. (over a 2 minute period). Repeat at 15 minute intervals, if necessary (max. 200 mg)
  • 1 month-12 years (by IV infusion); initially 500-1000 μg /kg body weight / hour adjusted at intervals of at least 15 minutes according to response. Max. 3 mg/kg/hour.

Note

Monitor BP every 5 minutes following each injection for all age groups.
Cease Labetalol injections if BP <140/90 mmHg and/or pulse <60 BPM in adults, (for children consult a paediatrician) or wheezing and bronchospasm occurs.

Or

Hydralazine, IV,

  • Adults: 5-10 mg slowly (over a 2 minute period), diluted with 10 ml Normal Saline (0.9%).
  • Repeat at 20-30 minute intervals, if necessary

Children

  • 12-18 years; 5-10 mg stat. Repeat every 4-6 hours, if necessary
  • 1 month-12 years; 100-500 μg/kg. Repeat every 4-6 hours, if necessary; max. 3 mg/kg daily (not exceeding 60 mg per day)
  • < 1 month; 100-500 μg /kg. Repeat every 4-6 hours, if necessary; max. 3 mg/kg daily

Note

Monitor BP every 5 minutes following each injection for all age groups.
Do not use short-acting nifedipine (e.g. sublingual) in the management of hypertensive crises as it lowers the BP too rapidly and may cause ischaemia of vital organs.

Referral Criteria

Refer all patients to a physician specialist for further evaluation.