THURSDAY, April 13, 2006 (HealthDay News) -- Children who suffer from frequent infections -- including something as seemingly benign as the common cold -- may also be sustaining damage to their hearts, a new study suggests.
Researchers found elevated levels of a protein in infection-prone children that, when seen in adults at the same level, indicates heart injury.
"When a family brings their sick child to the emergency room for problems such as colds, fevers, viruses, about 8 percent of those children had dying or death of the heart-muscle cells, even though it wasn't apparent to the child, family or treating doctor," said study author Dr. Steven Lipshultz, chairman of the department of pediatrics at the University of Miami Miller School of Medicine.
Almost 2 percent of the children had damage in the range seen in adults with a heart attack, he added.
But other experts point out that the study authors did not measure actual damage to the heart muscle, only blood levels of a protein called cardiac troponin I that, in adults, indicates injury.
"I don't think that we fully understand troponin levels in children," said Dr. Dianne Atkins, a spokeswoman for the American Heart Association and professor of pediatrics at the University of Iowa. "We often do get children in intensive-care units with high levels, and we never really understand what they mean or what we should do."
"I think that it would be helpful to do a study on a very broad spectrum of healthy children who have no illness to see if there is a baseline elevation" of the protein, Atkins added. "Do we know for sure that levels in children are the same as they are in adults? We've made that assumption but it's never been measured in children."
If higher troponin levels in children did indicate damage to the heart, the implications could be severe.
"We often do not know where unhealthy heart muscle leading to heart failure in young adults originates," Lipschultz said. "Yet there have been studies showing that someone in their 30s has a 50 percent mortality rate at seven years." In other words, half of adults diagnosed with cardiomyopathy -- severe weakening of the heart muscle -- during their 30s will die within seven years.
Repeated infections during childhood can lead to heart damage. If doctors could test or screen for such injury, they might be able to protect the heart from further damage, Lipschultz said.
For this study, which appears in the April issue of the American Heart Journal, the researchers measured blood levels of cardiac troponin I (cTnI) in 193 acutely ill children and 90 healthy children. All the participants had come to the emergency room at Children's Hospital in Boston. None had any outward signs of heart disease.
Almost 8 percent of the acutely ill children and 4.4 percent of the healthy children had elevated cTnI levels. These cTnI levels indicate a level of destruction equivalent to that seen in an adult with angina, which is chest pain caused by a lack of blood to the heart. Within this subgroup of children, 1.4 percent had blood levels of the protein equivalent to that found in adults who had had a heart attack, the researchers said.
The data also indicated that certain groups of children -- such as those who were younger, had low blood counts and high fevers -- might be at higher risk for injury to the heart muscle.
Blood protein levels were not cross-referenced with an actual surgical look at the heart muscle, which would be difficult and unethical to do, the researchers said.
Also, Atkins pointed out, the differences in the detection of cTnI levels were not statistically significant between the healthy and the sick children.
"I don't think that we can say children who develop viral syndromes, which is virtually all children, are then at high risk for developing problems later in life," she said.
The study did find that troponin levels were associated with other markers for heart damage.
"They all correlated, so it really suggests that this is real as opposed to artifactual," Lipschultz said. "At this point in time, the paper is informative for pediatricians and other health-care providers to say that in young children with high fevers and low blood counts, they may want to consider getting troponin levels and potentially involving a pediatric cardiologist."
The American Heart Association has more on children's heart health.