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School of Medicine
BLACK KIDS WITH HIGH BLOOD PRESSURE MAY BE AT HIGHER RISK FOR HEART DISEASE
Research led by the Johns Hopkins Children’s Center shows that black children with persistently elevated blood pressure are more likely than other hypertensive children to develop left ventricular hypertrophy (LVH), a dangerous enlargement or thickening of the left chamber of the heart. LVH, over time, can lead to heart failure, heart rhythm abnormalities and death.
In the study, black children with LVH also had higher cholesterol levels, a trend that was absent among children of other ethnicities, with or without LVH.
All children with untreated hypertension, regardless of race, are at risk for developing LVH over time, the Hopkins researchers say, but the new findings should be heeded as an alarm by pediatricians that black children may be at even higher risk.
In the study of 139 children with hypertension, ages 3 to 21, researchers found that of 35 black children, 60 percent had developed LVH, compared to 37 percent of the 104 children of other races.
“Our study identifies black children with hypertension as a special group who may be at particularly high risk for heart disease as they age because of several risk factors, and pediatricians treating these kids should follow them very closely,” said study lead author Cozumel Pruette, M.D., a kidney specialist at Hopkins Children’s.
An estimated 4 million children in the United States have hypertension, a number that has increased five times over the last 20 to 30 years, and researchers say the obesity epidemic is one possible factor in the increase.
All children, regardless of race, who have had one episode of elevated blood pressure during a visit to their doctor, should be monitored to make sure the episode was isolated rather than chronic, Pruette says. And all children who are diagnosed with hypertension should be referred to a kidney specialist and have an ultrasound study of the heart to check heart muscle thickness and heart function. Researchers recommend cholesterol checks for children with blood pressure at or above the 95th percentile; overweight children with blood pressure ranges in the 90th to 94th percentile (or pre-hypertension); in children with chronic kidney disease, and in those who have family history of hypertension and cardiovascular disease.
Co-investigators on the study: Barbara Fivush, M.D., and Tammy Brady, M.D., M.H.S., of Hopkins Children’s; and Joseph Flynn, M.D., M.S., of Seattle Children’s Hospital.
MEMO TO DOCS: MINIMIZE SCANS THAT EXPOSE YOUNG PATIENTS TO RADIATION WHEN POSSIBLE
Children with traumatic injuries get relatively high doses of radiation from imaging tests like CT scans and X-rays during evaluation in the emergency room and in the hospital, according to research from the Johns Hopkins Children’s Center. Radiation exposure is a known risk factor for cancer later in life, and children are believed to be more vulnerable to the effects of radiation because their tissues are still developing and their cells dividing more rapidly than those of adults, the scientists say.
The average radiation dose received by children in the study was nearly 13 mSv, for millisievert (a unit for radiation exposure), and the highest dose was 75 mSv. By comparison, the average American is exposed to 3 mSv per year from environmental sources, researchers say. And while a safe threshold for radiation exposure has not been defined, cancer risk is believed to go up in proportion to the amount of radiation received, with every single exposure causing a corresponding rise in cancer risk, according to a 2005 landmark report by the National Academy of Sciences.
Combing through a year’s worth of medical records, researchers studied the charts of 945 patients treated at Hopkins Children’s for traumatic injuries, calculating the cumulative radiation dose for each patient by adding all the imaging tests the patient underwent at the ER and/or the hospital, if subsequently admitted.
Patients who were admitted to the hospital after being brought to the ED, and had repeated radiological tests, had a higher average radiation exposure at 18 mSv, compared to an average of 8mSv for those who were evaluated in the ED and sent home. Burn patients had the lowest exposure (1 mSv on average), while those injured in car accidents had the highest exposure, 18 mSv.
On average, children had four to six imaging tests that exposed them to radiation, including X-rays, CT scans and fluoroscopy (a real-time X-ray used during certain surgeries). CT scans, which provide the most detailed three-dimensional images, carried the highest radiation exposure, followed by fluoroscopy and traditional X-rays.
The Hopkins team warns against unnecessary anxiety over too much radiation exposure from medical tests, but says trauma teams caring for these children must carefully weigh the benefits of quick diagnosis against the risk of too much radiation from multiple or repeated tests, especially if their diagnostic value is uncertain.
“In a trauma case, treatment decisions must be made in minutes, even seconds, and a CT scan can give a doctor invaluable information that could mean the difference between life and death,” says lead investigator Marissa Brunetti, M.D., a critical care specialist at Hopkins Children’s. “But all we’re saying here is, use CT scans and other radiation imaging tests sparingly and only when absolutely necessary, not as a diagnostic crutch. Ask yourself: Is another option, such as an ultrasound or careful observation, available?”
Principal investigator of the study: Robert Brown, M.D., of Hopkins. Other investigators include Mahadevappa Mahesh, Rosemary Nabaweesi, Susan Ziegfeld, and Paul Locke.
FLU SHOTS A MUST FOR KIDS WITH SICKLE CELL DISEASE
-Children with sickle cell disease hospitalized frequently with the flu
Children with sickle cell disease are hospitalized with influenza nearly 80 times more often than other children, a finding that should be a wake-up call for both pediatricians and health insurance providers, say researchers from Johns Hopkins Children’s Center.
In the study, the Hopkins team combed through records from several state databases tracking flu hospitalizations from the 2003-2004 and 2004-2005 flu seasons and found that 5,256 children were hospitalized with the flu. Among children with sickle cell disease, there were 201 flu-related hospitalizations per 10,000 children per year compared to 2.6 flu-related hospitalizations per 10,000 children among those without sickle cell disease per year.
The CDC considers children with sickle cell disease, a genetic disorder marked by abnormally shaped red blood cells, to be at high risk for complications from the flu. However, to date, there has been little evidence to prove it. The Hopkins report is the first study to quantify the risk and to show how often these children end up in the hospital with the flu, pointing to the need for aggressive immunization efforts in children with sickle cell disease, much like in children with other chronic conditions, including asthma, diabetes and heart disease.
“Kids with sickle cell disease are hospitalized often enough for their disease, and the last thing they need is to be in the hospital for a preventable complication,” says lead investigator David Bundy, M.D., M.P.H., of Hopkins Children’s. “We know from other studies that children with sickle cell disease get flu shots less than half of the time and may be overlooked as a risk category by doctors and insurance providers and within the sickle cell community itself.”
Because past research has shown dismal flu vaccination rates among children with sickle cell disease, Bundy and colleagues recommend that pediatricians treating these patients should have proactive immunization plans rather than wait to vaccinate children when and if they come to the office. Because sickle cell disease is a relatively rare condition, affecting 72,000 Americans, most pediatric practices do not have many sickle cell patients. Consequently, it would not be burdensome to launch proactive vaccination efforts, such as mail alerts and phone calls, Bundy says.
He adds that another way to mass-immunize children with sickle cell disease is through Medicaid-based vaccination efforts. Medicaid is the public health insurance program for low-income children. In the study, 64 percent of the children with sickle cell disease who were hospitalized with the flu were insured by Medicaid.
“Medicaid-based efforts could be that silver bullet of mass immunization for many U.S. children with sickle-cell disease,” Bundy says. “A cheap flu shot program could save millions of dollars by preventing flu-related hospitalizations, providing a great return on investment for Medicaid,” Bundy says.
Abnormal, crescent-shaped red blood cells that give the disease its name block the normal flow in blood vessels and can cause organ damage. Each year, 2,000 U.S. babies are born with the disorder.
The CDC recommends that all children over 6 months of age get a flu shot, except those who are allergic to eggs or have had a severe reaction to a flu vaccine in the past.
Other investigators in the study include John Strouse, M.D., Marlene Miller, M.D., and James Casella, M.D., all of Hopkins Children’s.
TEEN PARENTS OF CRITICALLY ILL NEWBORNS DON’T GET SEVERITY OF ILLNESS
research led by the Johns Hopkins Children’s Center shows that teen parents of critically ill newborns often do not fully grasp the severity of their baby’s condition. The findings should alert physicians to find ways to better gauge parents’ comprehension of the scope of their child’s illness and its implications, which is critical for the parents’ ability to make informed decisions about their child’s medical care, investigators say.
“It really boils down to: Make two-way communication with parents a top priority. Period,” said lead researcher Renee Boss, M.D., a neonatologist at Hopkins Children’s. “Ask probing follow-up questions to make sure they do get it. Ask them to summarize what they got out of the conversation and how they think it would affect their baby in the short term and in the long term.”
Boss and her colleagues interviewed 45 mothers under the age of 21 whose critically ill newborns were being treated in the Hopkins Children’s neonatal intensive care unit (NICU). The investigators found that while most (97 percent) could accurately name at least one of their baby’s diagnoses and two-thirds could name a treatment, among other details, they often did not realize the full scope of the condition, its severity and its implications. In fact, only 17 percent agreed with the healthcare providers about the seriousness of their infant’s condition. Teens were also reluctant to ask questions when they did not understand medical terms, researchers found.
Parental age and educational level did not affect understanding, which suggests the real issue may be provider communication rather than parental capacity, researchers said.
Co-investigators include Pamela Donohue, M.D., of Hopkins; and Robert Arnold, M.D., of Montefiore University Hospital, Pittsburg, Pa.
HIV TREATMENT LAGGING BEHIND FOR MANY INFECTED YOUTH
Research led by Johns Hopkins Children’s Center has found that many HIV-infected youth who meet criteria for treatment with HAART (highly active anti-retroviral therapy) either get no treatment or do not get it in the recommended time, which puts them at risk for complications and may speed up the progression from HIV infection to full-blown AIDS.
In a study of hundreds of HIV-infected youth seen in high-volume HIV clinics nationwide, researchers found that overall 43 percent of the 656 who qualified for treatment by one of several criteria were not given HAART, the gold standard of HIV therapy to ward off complications, restore immunologic function and reduce the risk of infecting others.
Treatment criteria have evolved since 1997, when HAART became available, but currently most HIV experts agree that anyone with a CD4 cell count below 350 per cubic milliliter of blood should start HAART. CD4 cells, immune cells that are a favorite target of HIV, are slowly destroyed as the disease progresses. Other HIV care providers may rely on different criteria, prescribing HAART only to those with a viral load above 100,000 per cubic milliliter of blood regardless of CD4 count, or HAART treatment only for those who have both high viral load and low CD4 count. Using all three criteria, separately and in combination, the researchers assessed initiation of HAART.
Applying the most stringent definition of who should get treatment — those who had both high viral loads and low CD4 counts – researchers found that 26 percent of the 227 youth who qualified by this standard did not get therapy. Among those who qualified for treatment by CD4 count alone, 50 percent of 142 did not get treatment. Among 63 who qualified for HAART by viral load alone, 55 percent did not get treated.
Teenagers and young adults traditionally have been the hardest group to treat because they often miss appointments and find it hard to follow the complicated multidrug regimens that make up HAART. However, frontline HIV care-providers must realize that they too are part of the equation, the researchers say, and find ways to increase both initiation and compliance with HAART.
“We’re not blaming anyone, but it takes two to tango: Teens should want to be treated, and providers should persist in treating them,” said lead investigator Allison Agwu, M.D., an infectious disease specialist at Hopkins Children’s. “We must figure out just why it is that we’re not treating so many of these young people and, once we do, design better strategies to get them on timely treatment.”
According to the CDC, there are 53,000 new HIV infections diagnosed each year in the United States, and 14 percent of these infections occur in 13- to 25-year-olds.
Other Hopkins investigators in the study include Jonathan Ellen, M.D., and Kelly Gebo, M.D.
Other institutions in the study: Children’s Hospital of Philadelphia, St. Jude’s Children’s Research Hospital, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, University of California-San Diego, St. Luke’s-Roosevelt Hospital, New York.
Johns Hopkins Children's Center
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