Page created on February 20, 2022. Not updated since.
Definition
In childhood, blood pressure correlates better with height than body weight or age, and so when defining blood pressure standards, height is taken into account. Hypertension in childhood is defined as the following in children 1 – 13 years:
| Age group | Degree of hypertension | Value |
| Age 1 – 13 years | Normal BP | < 90th percentile |
| Elevated BP | 90th – 95th percentile OR:
120/80 mmHg – 95th percentile |
|
| Stage 1 hypertension | 95th percentile – 95th percentile + 12 mmHg OR:
130/80 – 140/90 mmHg |
|
| Stage 2 hypertension | > 95th percentile + 12 mmHg OR:
> 140/90 mmHg |
|
| Age 13 – 18 years | Normal BP | < 120/80 mmHg |
| Elevated BP | 120/80 – 130/80 mmHg | |
| Stage 1 hypertension | 130/80 – 140/90 mmHg | |
| Stage 2 hypertension | > 140/90 mmHg |
If a child has stage 2 hypertension and signs or symptoms of severe hypertension, it’s called emergency hypertension. White coat hypertension is the phenomenon where a patient has hypertension when measured in-office, but not on ambulatory blood pressure monitoring.
Etiology
The younger the child, the higher the chance that the blood pressure is secondary rather than primary. In adolescents, primary hypertension is most common; in younger children, secondary is most common.
Possible causes of secondary hypertension include renoparenchymal (glomerulonephritis, polycystic, chronic kidney disease), renovascular (renal artery stenosis), vascular (coarctation of the aorta), endocrine (CAH, Cushing syndrome), and CNS (increased ICP) causes.
Evaluation
Blood pressure measurement is indicated for all medical contacts for children > 3 years old, and children < 3 years old in special circumstances:
- Prematurity
- Neonatal complications
- Congenital diseases
- Recurrent UTI
- Family history of congenital kidney disease
- Cancer
- Systemic illness associated with hypertension
- Taking drugs which can cause hypertension (steroids, oral contraceptives)
When measuring, it’s important to choose an appropriate cuff size. The cuff bladder should cover 80 – 100% of the circumference of the arm. As for adults, the child should rest for at least 5 minutes before measurement. The measurement should take place in a sitting position with the back supported, with the feet on the floor and the cubital fossa at the heart level.
If the average of 3 independent, occasional blood pressure values show hypertension, ambulatory blood pressure monitoring is recommended. This can rule out white coat hypertension, shows diurnal changes in the blood pressure, and can be used to monitor effectivity of treatment.
It’s important to ask about clinical signs of hypertension, which is usually a sign of severe hypertension. These include headache, nausea/vomiting, encephalopathy, and visual disturbance. It’s also important to ask about family history of disorders which could cause secondary hypertension.
During physical examination, it’s important to look for signs which could indicate an underlying disorder. These include:
- Obesity – sign of endocrine or chromosomal disorder (or idiopathic)
- Rickets – sign of chronic kidney disease
- Virilisation – sign of endocrine problem
- Signs of Cushing syndrome – sign of endocrine problem
- Café au lait spots – sign of neurofibromatosis type 1 (Recklinghausen disease)
- Soft, weak femoral pulse – sign of coarctation of the aorta
In those children where secondary hypertension is a possibility based on history and physical examination findings, it’s important to measure certain laboratory parameters, include kidney function tests, electrolytes, arterial blood gas, CBC, glucose, renin and aldosterone levels, urine analysis, and urinary catecholamines. Other investigations which may be useful include echocardiography, abdominal ultrasound, scintigraphy, angiography, and abdominal CT.