What is Pediatric Hypertension?
Unlike in adults where a systolic blood pressure (upper reading of the blood pressure measurement) of more than 140 mm of Hg and a diastolic blood pressure (lower reading of the blood pressure measurement) of more than 90 mm of Hg is defined as hypertension.
- If the blood pressure values are between the 90th percentile and 95th percentile, the condition is classified as prehypertension.
- Readings between the 95th and 99th percentile plus 5 mm of Hg amount to stage I hypertension.
- Readings above the 99th percentile plus 5 mm of Hg are considered as stage II hypertension.
How Common is Childhood Hypertension?The prevalence of hypertension in childhood is about 4-5%. It is slightly more common in the male child.
A study in South India found that the prevalence of prehypertension and hypertension was similar in urban (2.9% and 2.8%) and rural (2.8% and 2%) school children in the age group of 10 to 16 years.
What are the Causes of Pediatric Hypertension?Causes of hypertension in general are classified as primary and secondary.
Primary hypertension is when the patient does not have an underlying cause for hypertension, while secondary hypertension occurs due to an underlying cause.
In the pediatric age group, secondary hypertension is more common than primary hypertension. This is particularly true in younger children. However, reports do indicate that atherosclerosis (hardening of the arteries) does exist in childhood and maybe associated with childhood hypertension. Common causes of secondary hypertension are:
- Kidney-related conditions like renal artery stenosis, thrombosis and congenital anomalies
- Coarctation of aorta, which refers to narrowing in the largest artery of the body called the aorta
- Hormonal conditions like pheochromocytoma and Cushing’s syndrome (high glucocorticoid levels in the body)
- Drug abuse
- Heart defects like ventricular septal defect
- Genetic causes
- Problems with sleep like sleep apnea
What are the Signs and Symptoms of Pediatric Hypertension?Hypertension is termed as the “silent killer” because it usually does not exhibit any signs or symptoms. In advanced stages, the child may develop symptoms like:
- Shortness of breath
- Visual disturbances
- Nose bleeds
- Seizures in later stages
Some of the signs to watch out for are:
- Bluish discoloration of the skin
- Pale skin
- Excessive irritability
- History of prematurity, very low birth weight, or who have had undergone interventions in a neonatal intensive care unit
- Congenital heart disease
- Known renal or urological diseases with blood or protein in urine
- Family history of congenital kidney disorders
- Following organ transplant
- Conditions like neurofibromatosis (genetic disorders that cause tumor to grow in the nervous system), tuberous sclerosis and ambiguous genitalia
- Recurrent urinary tract infections
How Do You Diagnose Pediatric Hypertension?History and Physical Examination
The doctor takes an authentic history of the family and looks out for the signs and symptoms which are mentioned above. The blood pressure should be immediately measured in children who present with symptoms of target organ damage like headache, dizziness, confusion, irritability or seizures. An eye examination is also necessary to rule out damage to the eyes due to hypertension.
The symptoms of an underlying cause of the high blood pressure may also be apparent in the patient.
Blood Pressure Measurement
The blood pressure is measured with an instrument called a sphygmomanometer, the same instrument used to measure blood pressure in adults. In children however, special cuffs of smaller size are used.
The blood pressure should be measured in the sitting or lying down position after the child has rested for 5-10 minutes. The right arm is used for consistency in measuring blood pressure. The pressure may have to be measured in all four limbs to detect coarctation of aorta.
Ambulatory blood pressure monitoring is done by measuring blood pressure continuously over 12-24 hours. It can rule out a situation called white coat hypertension, where the blood pressure of the child increases on coming in contact with a doctor. It is also used to monitor response to treatment. Any abnormal reading noted during ambulatory monitoring should be cross-checked using a sphygmomanometer.
The following blood tests are done in a child with hypertension:
- Complete blood count – To rule out anemia
- Basic metabolic profile and electrolyte levels – To rule out endocrine causes
- Urea and creatinine levels – To rule out kidney causes of hypertension
- Fasting lipid profile and glucose – To find out any existing metabolic problems like diabetes and high cholesterol
The urine sample is collected and tested for the following:
- Urine analysis - To determine renal causes of hypertension
- 24 hours urine protein – To rule out kidney-related and endocrine causes of hypertension
- Abdominal ultrasound – An ultrasound is done by applying gel to the skin of the abdomen and running a probe over it. The procedure is not painful. The test helps to visualize the kidneys and rule out kidney cause of hypertension.
- Chest x ray, electrocardiography (ECG) and echocardiography (Echo) – These tests are done to rule out cardiac causes and to check for damage to the heart
- Computed tomography (CT scan) of head. - A CT scan of the head may be necessary if neurological signs are present
How Do You Treat Pediatric Hypertension?Lifestyle modifications are necessary for prehypertension and hypertension, while hypertension may also require treatment with medications. The underlying cause of hypertension when present should be treated.
- Weight reduction which should be achieved with diet modification and increased physical activity
- Children are encouraged to do physical activities like cycling, swimming, running and playing with friends
- Diet modification in the form of low salt intake. Daily intake of 1-1.5 gram of sodium is recommended
- The parents should be instructed that a regular follow-up to measure blood pressure is necessary for these children.
- A heart healthy diet should be followed. The intake of fried foods and sweet snacks should be avoided while the intake of fresh fruits and vegetables should be encouraged.
Treatment with Medications
There is no consensus on the best initial antihypertensive medication to use in children. Treatment with medications may be needed in children with symptoms, end organ damage, secondary hypertension and in those whom the blood pressure is not controlled with lifestyle modifications.
Drugs which are used in hypertensive children are as follows:
- ACE inhibitors like fosinopril, enalapril, and lisinopril which act through multiple mechanisms
- Calcium channel blockers like amlodipine which relax blood vessels and reduce the work of the heart
- Beta blockers like propranolol and metoprolol which reduce the work of the heart
- Central alpha agonists like clonidine which relax blood vessels
- Drugs like hydralazine and minoxidil which relax blood vessels
- Diuretics like hydrochlorothiazide which reduce the water content of the body
How Do You Prevent Pediatric Hypertension?Pediatric hypertension may be prevented by:
- Early identification of risk factors like family history of hypertension, low birth weight, overweight and sedentary lifestyle
- Annual measurement of blood pressure in children more than 3 years is highly recommended.
- Universal lipid screening for children from 9-11 years is now recommended to detect abnormal lipid and cholesterol levels
- Promoting sleep hygiene in children and ensuring that children get adequate sleep
- Parenteral control on children’s use of Internet, video games and mass media. Active video games should replace the ones that make children couch potatoes
- Recommending increased physical activity in children
- Early identification of risk factors and secondary causes of hypertension in children is very important
- Low salt intake to be followed in children who are at risk for developing hypertension
- Signs like irritability, headache and blurring of vision in children should not be ignored
- Lifestyle and diet modification is very important as a first line of treatment in children with essential hypertension