Unraveling the Causes of Infant Deaths
Sometimes, SIDS may not be the true culprit
SUNDAY, Aug. 12, 2001 (HealthDayNews) -- A new blood test may help determine whether a metabolic disease actually should be blamed for some infant deaths originally attributed to SIDS.
Researchers using a blood sampling process called tandem mass spectrometry tested blood samples from 7,058 infants whose deaths initially were attributed to SIDS, or sudden infant death syndrome -- a moniker given the unexplained and sudden death of a child less than a year old.
However, 66 of the infants whose blood was tested actually had suffered from a potentially fatal metabolic disorder, the study says.
Such disorders typically are inherited and include a condition that causes the body to have problems breaking down fatty acids, known as an MCAD deficiency, or medium-chain acyl coenzyme A dehydrogenase deficiency.
The study results illustrate that the real causes of other infant deaths originally tied to SIDS could be uncovered with a little more work, says lead researcher Donald H. Chace, chief of the division of bioanalytical mass spectrometry at Neo Gen Screening, a Pennsylvania lab that offers various types of screenings for newborns.
"There's a real problem in how medical examiners determine SIDS," Chace says. "Infants simply don't die for no known reason. There's always a reason."
But determining a cause of death can have far-reaching consequences, he says. For one thing, he says, other causes or suspicions can be ruled out.
"We do a lot of ruling out of potential cases of shaken baby syndrome," Chace says.
"Doctors will have seen hemorrhaging in the brain and the baby looks like it had been battered," he says. "The parents may have been under suspicion, but the metabolic disease will have caused the symptoms and was the cause of death."
Also, because metabolic conditions are inherited, discovering that a child's death resulted from such a condition can prompt testing for other family members.
"We picked up a metabolic disease in a child that the family thought had died of an infection," Chace says. "And by finding that out, they found that an older child in the family had the disease as well, and that was important to know." Details of the study appear in a recent issue of the journal Clinical Chemistry.
Testing via tandem mass spectrometry is being used more and more both by medical examiners and in newborn screenings at some hospitals, says Dr. Hegyi Thomas, director of neonatology at the Robert Wood Johnson Medical School in New Brunswick, N.J.
But adopting it for widespread use is more complicated than it sounds, she says.
"The problem is that you can't screen babies without having a whole system of follow-up in place," Thomas says. "There have to be lots of resources to rescreen in case there are false positives and false negatives."
"In addition, there has to be follow-up in terms of family communication, counseling and intervention, and all of that requires resources," she says.
"It's all very expensive, so you wind up having to go to the legislature and ask for money for it, and then taxes have to be raised, and then you're talking about the whole issue of health-care management," she adds.
About 25 percent of all babies who die before they reach age 1 are termed SIDS deaths, Chace says. Such deaths sometimes are called "crib deaths" because they almost always occur while babies are sleeping.
But, he adds, 3 percent to 6 percent of those deaths are likely due to inherited metabolic disorders.
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