Hypertension

Measurement of blood pressure

A good measurement of the blood pressure is important, and more than one measurement is needed. The cuff should be 2/3 of the length of the upper arm. When the cuff is too small, it will give a falsely high reading. When too big, it will be falsely low.

Normal systolic blood pressure:
80 + (age in years x 2)

Diastolic blood pressure: 2/3 of systolic blood pressure

AGE	SYSTOLIC BP
Newborn (term)	50 to 70 mm Hg
Under 1 year	70 to 90 mm Hg
1 to 5 years	80 to 100 mm Hg
5 to 12 years	90 to 110 mm Hg
Over 12 years	100 to 120 mm Hg

General

Longstanding hypertension will give cardiovascular and cerebrovascular damage. A hypertensive crisis will cause encephalopathy and retinopathy. Causes

Renal disease (commonest cause in children)
- Glomerulonephritis
- Haemolytic uraemic syndrome
- Renal failure
- Cystic renal disease
Renovascular
- Renal artery stenosis
Cardiovascular
- Coarctation of the aorta
Endocrine
- Cushing
- Neuroblastoma
Essential

Important points in history

Headache, visual disturbances, fits, vomiting, shortness of breath, frequent nose bleeds

Important points in examination

Repeated measurements of blood pressure in arms and legs (?coarctation of aorta) - Cuff size 2/3 of arm/calf
Cardiac exam, including femoral arteries
Renal artery bruit in abdomen
Fundoscopy

Investigations

Try to find the cause of the hypertension, dependent on history and examination. For example:

Creatinine, Urea, Electrolytes
Urine dipstick and urine microscopy
USS of kidneys and heart
Chest x-ray

Treatment

General Treatment

When obese: lose weight
Diminish salt intake

Drug Treatment

When hypertensive crises/ encephalopathy or chronic hypertension: aim to reduce the BP to normal levels over 48-72 hours. (Rapid reduction may cause stroke or blindness).

Treatment depends on availability.
Try to start with a short-acting drug, like nifedipine or hydralazine.
In case of fluid overload, start with diuretics.
Be careful with ACE-inhibitors when renal hypoperfusion is a possibility (e.g. renal artery stenosis or aortic coarctation) or in infants. ACE inhibitors are otherwise not contraindicated in hypertension.

CA-ANTAGONISTS
Nifedipine PO - 0.25 mg/kg 3-4x/day (max 2 mg/kg/day)

ACE-INHIBITORS
Captopril PO - 0.1 mg/kg 2-3x/day, max 6 mg/kg/day
Lisinopril PO - 70 microgram/kg 1x/day (max 600 microgram/kg/day)
Enalapril PO - start with 2.5 mg OD in children 20-50kg (max 20 mg/day)
start with 5 mg OD in children >50 kg (max. 40 mg/day)

DIURETICS
Spironolactone PO - 1-3 mg/kg/day divided into 1-2 doses
Furosemide PO - 1-4 mg/kg/day divided into 1-2 doses
Hydrochlorthiazide PO - 1-4 mg/kg/day divided into 1-2 doses

BETA-BLOCKERS
Atenolol PO - 0.5-2 mg/kg OD
Propranolol PO - 1-5 mg/kg/day divided into 3 doses

OTHER
Hydralazine PO - 0.5 mg/kg BD or TDS (max 7,5 mg/kg/day)
Hydralazine IV - 0.1-0,5 mg/kg 4-6x/day
Alpha methyldopa - 5-20mg/kg per dose BD or TDS

Follow up

in general clinic