PHILADELPHIA — Hypertension, often called a condition without its own symptoms, manifests through heart attacks and strokes.
But a new study by researchers at the Texas Children's Hospital claims that children with hypertension may actually have symptoms such as headache and chest and abdominal pain, but that these signs are overlooked, according to Dr. Daniel I. Feig, who is chief of the hospital's pediatric hypertension clinics. He presented the results at the annual meeting of the American Society of Nephrology.
Dr. Feig and his colleagues studied 409 consecutive children who were evaluated at the facility's pediatric hypertension clinics for new-onset high blood pressure.
An estimated 2%–3% of children under age 18 years, and 15%–30% of obese children, have elevated blood pressure. Most of these children go undiagnosed, or are not managed well, he said. But it's important to address the hypertension early, he said, noting that the majority of hypertensive children go on to have elevated blood pressure as adults.
In adults, the poor outcomes are measured through heart attacks, strokes, or kidney failure, but in children, those events are rare. Some studies have shown evidence of organ damage in hypertensive children, including left ventricular hypertrophy, proteinuria, and accelerated atherosclerosis.
Clinicians use a statistical definition to quantify hypertension in children. Dr. Feig said he and his colleagues diagnosed hypertension when a child had a blood pressure greater than the 95th percentile, stratified for age, gender, and height, on three consecutive visits, over a 2-week time frame. They relied on charts from the Fourth Report on the Diagnosis, Evaluation and Treatment of High Blood Pressure in Children and Adolescents (Pediatrics 2004;114:555–76).
The researchers aimed to diagnose hypertension earlier in children and quantify the potential adverse outcomes if left unmanaged. They asked 409 consecutive children (aged 7–18 years) to fill out a questionnaire requesting self-reporting of 15 symptoms likely related to high blood pressure. After excluding those children who did not meet the entry criteria, they evaluated the questionnaires of 343 children and compared them with 150 healthy controls.
Children were asked to put a check next to a symptom that bothered them more than once a week. Of those with elevated blood pressure, 64% complained of more than one symptom, compared with 26% of normal children, a significant difference; 51% had one to four symptoms, and 14% had more than four symptoms.
The three most common symptoms were headache, which affected 42% of the hypertensive children, difficulty falling asleep, which affected 27% of that group, and daytime tiredness, which affected 26%. The hypertensive children were five times more likely to have these symptoms than normal children (odds ratios of 5.49 and 5.96, respectively).
Children also complained of chest and abdominal pain, failing at school, and having trouble concentrating.
The hypertensive children received counseling on how to modify their diets and were told to start exercising (low-impact cardiovascular training for 30 minutes a day for the sedentary kids). Children with severe hypertension or those who had elevated pressure due to a renal, cardiac, or another underlying condition were started on antihypertensives immediately. For the others, if they did not improve after 2 or 3 months of lifestyle changes, pharmaceuticals were added.
The most commonly used drugs included ACE inhibitors and calcium channel blockers.
Investigators asked the children to repeat the survey 4–6 months after starting treatment. Treatment seemed to make a substantial difference in the most common symptoms, with only 6.2% complaining of headache, down from 42%. Only 1.5% of children reported trouble falling asleep, and only 10% complained of daytime fatigue.
There was also a fairly big reduction in chest and abdominal pain, but there was no change in the number of children reporting difficulty at school—possibly because there was not enough time to detect a subjective change in school performance, or, more ominously, said Dr. Feig, because it might be that “cognitive changes due to early hypertension are irreversible.”
Children who received treatment improved regardless of whether they altered their lifestyle or took medications, suggesting that the most important intervention was lowering blood pressure, he said.
Dr. Stephen Daniels, a professor of pediatrics and environmental health at the Cincinnati Children's Hospital Medical Center, said the study challenges the conventional wisdom that hypertension is silent, but he was not convinced the symptoms were related to high blood pressure, citing potential design flaws.
The study “has generated a hypothesis that needs to be tested more completely,” he said in an interview. Hypertension is underdiagnosed in children, partly because pediatricians aren't always focused on measuring blood pressure or on how to interpret the measurements, he added.