Blood may pump through the veins faster for various reasons. You may be exercising, where the exertion makes your heart beat faster. You may be in a fight-or-flight situation where an adrenaline rush increases your heart rate. Or, worse, blood might be flowing in the body at a pressure higher than normal. And in most cases, people aren’t aware of this dangerous but silent condition.
Most people think these scenarios are limited to adults, but high blood pressure or hypertension exists even in children.
So, how different is hypertension in children?
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The pressure at which blood flows through the circulatory system increases due to factors such as obesity and comorbid conditions (like thyroid and kidney problems). This elevated pressure of blood flow is known as hypertension.
There are two main types of hypertension: primary and secondary. Primary hypertension is also called essential hypertension, which is common in adults but not so in children. It may be due to genetic factors or other unknown causes.
High blood pressure in children
Hypertension is diagnosed differently in children as compared with adults. The latest guidelines for clinical practice by the American Academy of Pediatrics say that children under the age of 13 are considered hypertensive if their blood pressure reading (taken on three different occasions) is at or outside the 95th percentile for their age, sex and height.
In case of adolescents (13 years or older), hypertension is defined as when blood pressure is equal to or more than 130/80 regardless of age, sex or height.
“It’s not that once we find a high blood pressure reading in the OPD, we call them hypertensive and start medication. White coat hypertension (where a child’s blood pressure rises because they are afraid of the doctor) maybe one reason,” says Dr Yogesh Kumar Gupta, consultant-paediatrics at Fortis Hospital, Bengaluru. “So, we tell them (the parents) to keep checking blood pressure either at home or at a nearby clinic, document the values over a span of 1-2 weeks and then we can review the readings.”
What causes hypertension in childhood?
“We are seeing more cases of paediatric hypertension these days,” says Dr Karthik Badarayana, paediatrician and paediatric rheumatologist at MS Ramaiah Memorial Hospital, Bengaluru, pointing to obesity and other lifestyle changes as the chief culprit. “Another reason [for the increase in number] may be that we started screening for hypertension in children only in recent years. The detection of kidney diseases is higher now compared to before. The more you screen for kidney and heart diseases, the more you find out that those children tend to be hypertensive.”
Primary hypertension (also known as essential or idiopathic hypertension) is a type of high blood pressure which does not occur due to secondary causes such as renovascular disease, kidney failure or genetic conditions.
It can also be spotted in childhood. Age has a significant influence on blood pressure, so knowing the blood pressure reading in childhood can help predict the same in adulthood. Moreover, the significant damage to the heart and kidneys caused by long-term hypertension can be prevented by identifying the signs during childhood.
“The rule is that the younger the child with high blood pressure, the more likely for the child to have underlying problems such as in the kidney, heart or any other chronic problems,” says Dr Gupta. “If the child has any of these problems, we always look for hypertension. We call this secondary hypertension.”
Hypertension is diagnosed in children based on height, age and sex of the child; the process is not as straightforward as in adults with a single threshold of 140/90 mmHg used to diagnose them with hypertension.
While measuring blood pressure, the child must be calm. This makes accurate measurement in crying children difficult. The cuff for measuring blood pressure must be of the right size for the child’s hand. Children must be tested for high blood pressure on three separate occasions to be diagnosed. Because of such risks of inaccuracies, hypertension in children often goes undiagnosed.
The kidney problem
Dr Badarayana cites chronic renal failure as the most common cause of hypertension in children followed by congenital heart disease, kidney diseases, endocrine problems like hypothyroidism, hyperthyroidism or steroid, and medication-related hypertension.
Among children, secondary causes for hypertension are more common than in adults. These include congenital defects in the kidney, heart or other organs.
“Chronical renal failure could be genetic because of certain medicines, X-ray exposure or some lifestyle changes which may not be identified during pregnancy,” he says. “In some situations, there may be blockage in the kidney or the bladder which won’t cause renal failure immediately but five to 15 years later.”
Another reason why kidney problems might occur is infection, where infants in the neonatal intensive care unit (NICU), they may get sepsis and go into renal failure.
Congenital renal problems in children are often undiagnosed or untreated because they are asymptomatic unless a test or an ultrasound is conducted. The kidneys endure more damage and blood pressure rises, leading to renal failure.
“Then, it becomes a vicious cycle,” says Dr Gupta. “Renal disease leads to hypertension, and hypertension in turn starts killing the kidneys. It becomes an irreversible process, which is quite common.”
Polycystic kidney disease, vesicoureteral reflux (where the urine flows back to the ureters), renal agenesis (congenital absence of the kidneys where some children have only one kidney from birth), dysplastic kidney, renal artery stenosis, acute renal failure and chronic renal failure are some common kidney diseases seen in children.
What to watch out for
“If someone comes to me with recurrent headaches, giddiness, a strong family history of hypertension, and if I pick some signs of hypertension like a problem with some organ, then I will definitely be careful about checking their blood pressure,” says Dr Gupta, explaining some ways to identify hypertension.
A study found that childhood hypertension starts increasing rapidly from the onset of puberty and peaks at the end of puberty, which may be associated with hormonal changes and growth spurts.
“In children, there is little difference in gender when it comes to hypertension,” says Dr Badarayana. “Older females are better protected because the oestrogen helps reduce blood pressure. But during adolescence (ages 15 to 20), girls are at risk of getting PCOS (polycystic ovarian syndrome), which is a risk factor for hypertension.”
Childhood obesity, especially abdominal obesity, is seen as a major cause for the reported increase in blood pressure among children in the recent past. Among the contributing factors are the consumption of foods with high saturated and trans-fat content along with having a sedentary lifestyle.
“Obesity is complex,” says Dr Gupta. “There are hormonal changes, body mass changes and metabolic syndrome where because of the increased weight, the body develops a resistance to insulin, and metabolism becomes abnormal.”
Treating hypertension in children
It’s important to understand the cause of hypertension. If it is related to lifestyle, then children should be encouraged to avoid a sedentary lifestyle and get some physical activity.
Some basic tests as indicated by the doctor such as deranged lipid profile, testing sugar levels and others like the thyroid function test checking for hypothyroidism which can lead to weight gain may be carried out by the parents.
“Irrespective of whether the values are elevated or not, we don’t jump to conclusions and start the child on pharmacotherapy. It’s not required,” says Dr Gupta. “If we can make some lifestyle modification, follow proper diet, regular physical activity, yoga and meditation, this can be reversed.”
Primary hypertension or lifestyle-related hypertension can be controlled without medication, with just exercise, diet and other lifestyle changes. Playing outdoor sports for at least an hour a day will have a positive effect on their health. Diet can also be modified by reducing foods which contain high amount of salt (like pickles) and foods with high fat and trans-fat.
“In case of secondary hypertension which is caused by any structural abnormality like kidney failure, heart defect or congenital heart disease, lifestyle changes alone won’t solve the problem,” Dr Badarayana says. “If the child is diagnosed with a medical condition which causes hypertension, then treatment should be focused on that condition, be it kidney or heart disease, hypothyroidism, PCOS or anything else.”
Children are different from adults, Dr Gupta says. Boosting their confidence and giving them positive reinforcement when they follow the routine their parents give them help children manage their lifestyle in the long run.
“I remember a child (who is obese) who had come in with high fever. Instead of talking about his cough and fever, he said, ‘Doctor, I lost 2 kgs this time.’ I didn’t even ask him about his weight. And the boy is hardly six years old, so imagine to what extent we can motivate them. It’s easier than with adults, I would say.”
Since the symptoms of hypertension are silent, one never knows if a child (or an adult) has it. It is more crucial in the case of children, therefore, to get their blood pressure checked regularly.
Keeping an eye out for conditions which may cause hypertension — such as those related to obesity, the kidneys and the heart — will make it possible to spot the problem early and treat the root cause. This way the child can be equipped to take sufficient precautions even in adulthood.
