Acute Severe Hypertension

Causes of hypertension

Investigations

Immediate management

General measures

Medicine treatment

Referral

Always measure blood pressure in the emergency room and at any paediatric consultation. Remember to use the correct size cuff. Hypertension is defined as systolic and/or diastolic blood pressure > the 95^th 

percentile for gender, age and height percentile on at least three consecutive occasions. 

• Systolic BP > 95^th centile for gender, age and height 
• Formula: 1-10yrs: (Age x 3) + 100 mmHg = 95^th percentile. 

Causes of hypertension

Hypertensive emergency/crisis exists when CNS signs of hypertension appear such as encephalopathy, convulsions, retinal haemorrhages or blindness. Great care is required to reduce the blood pressure in a controlled manner to avoid potentially serious consequences of impaired auto-regulation of cerebral blood flow. 

Hypertensive urgency (BP > 95th centile X 1.5) is defined as a significant elevation of blood pressure without accompanying end organ damage. Patients are generally symptomatic with complaints of headache, blurred vision and nausea, despite the lack of end organ involvement. 

Investigations: 

• FBC / U&E / C3 + C4 / Anti-DNase B / ASOT 
• Urine dipstix for blood/proteïen (formal protein if positive) 
• CXR / ECG / Cardiac Echo 

Further investigations: Ultrasound Kidney, ureter, bladder / Doppler Renal Artery / MCUG / CT Scan Brain and Kidney / DMSA and MAG3 isotope scan / Serum Cortisol / Urinary catecholamines 

Immediate Management 

Hypertensive emergency should be treated in ICU with invasive BP monitoring and with continuous infusion as inadvertent severe BP drop may cause a stroke or spinal cord infarct. Rate of BP reduction depends upon starting BP and age of the child. In the absence of central nervous system signs, acute hypertension can be rapidly controlled over 24 hours. If in doubt about the duration of hypertension, reduce BP slower over 48 hours. Aim to reduce the BP by about a third of the interval between the patient’s systolic blood pressure and the 95th percentile for that age or height in the first 8 hours, then a further gradual decline over the next 24–48 hours. Do not decrease BP to < 95th percentile in first 24 hours. 

General measures 

• Admit patient to paediatric intensive care unit, if possible. 
• Monitor BP every 10 minutes until stable, thereafter every 30 minutes for 24 hours. 
• Set up two peripheral intravenous drips. 

Medicine treatment 

• For acute severe hypertension use stepwise approach as discussed with Paediatrician. Do not combine medicines of the same class. 
  • Furosemide IV, 1–2 mg/kg as a bolus slowly over 5 minutes (oliguric: 5 mg/kg). ADD 
  • Labetalol IV, 0.5–3 mg/kg/hour (infusion pump) 100 mg in 80 mL NaCl 0.45% = 1 mg/mℓ. Give bolus of 0.5 mg/kg and then titrate the dose slowly upwards until the desired blood pressure is achieved. Repeat based on BP response. Alternative is Atenolol 0.5–1 mg/kg PO once daily. Contraindicated in severe heart failure and asthma. 
• If there is an inadequate response: ADD 
  • Amlodipine, oral, 0.2 mg/kg/dose. May be repeated after 12 hours, thereafter every 24 hours. 
• If phaeochromocytoma suspected use an alpha blocker instead of amlodipine while tapering labetalol: 
  • Prazosin, oral, 12 hourly. 1 month to 18 years: 0.5–1 mg/kg adjusted according to response. 

Subsequent management: 

• Decrease BP slowly over 3 – 4 days. 
• Use appropriate antihypertensives for specific condition. 
• With nephritis, hypertensive crisis may occur due to fluid overload and may present with LV failure and pulmonary oedema. See post Strep glomerulonephritis protocol. 
• Exclude raised intracranial pressure as a cause – if it is a cause, then high BP may be needed to perfuse the brain – consult consultant before treatment. 
• Stop seizure with IV Lorazepam / Rectal or IV Diazepam / Intranasal or IV Midazolam 

Referral 

• Urgently severe hypertension for specific diagnosis and treatment 
• All children with acute and chronic hypertension for specific diagnosis, planning of 
• treatment and long-term follow-up 
• Persistent cough on treatment with ACE inhibitor