Brainstem Failure & SIDS

Study: Babies of sudden infant death syndrome may be due to brainstem abnormalities.

Researchers at Boston Children’s Hospital report that babies dying suddenly and surprisingly, in both safe and unsafe sleep environments, have inherent brainstem abnormalities and aren’t all standard before death.

The researchers also point to the necessity to find and treat this inherent exposure early, the focus of their present work. They report their findings in the December Quandary of Pediatrics.

The researchers, led by Hannah Kinney, MD, a neuropathologist at Boston Children’s, have demonstrated in the last two decades that babies who die suddenly, unexpectedly and without explanation-whose departures are usually credited to sudden infant death syndrome (SIDS)-have differences in brainstem chemistry that set them apart from babies dying of other causes.

These abnormalities impair brainstem circuits that help control respiration, heart rate, blood pressure and temperature control during slumber, and, the researchers consider, prevent sleeping infants from rousing when they respire too much carbon dioxide (due to insufficient ventilation) or become overheated (from overbundling).

At exactly the same time, epidemiologic research show that babies dying suddenly and surprisingly are frequently seen in unsafe sleep environments, including sleeping face down with their face in the pillow, or sleeping with someone else in the bed.

In the brand new study, Kinney and co-workers inquired if these babies are actually standard. They reexamined their data, reviewing the instances of 71 babies who died suddenly and surprisingly, were autopsied at the San Diego County Medical Examiner’s office from 1997 to 2008, and had brainstem samples available for evaluation. The researchers grouped the babies according to sleep conditions-those considered safe (asphyxia not likely) or dangerous (asphyxia likely) based upon death-scene investigation reports.

Finally, they compared 15 babies with SIDS whose departures were deemed not to entail asphyxia (group A), 35 SIDS babies whose deaths were potentially asphyxia-associated (group B) and 9 babies who certainly died from other causes (controls). They excluded the other babies, who either had inadequate data or had signs of other clear risk factors for departure, including exposure to drugs or extremes of temperature.

“Even the babies dying in unsafe sleep environments had an inherent brainstem abnormality that probably made them vulnerable to sudden death if there was any level of asphyxia,” Kinney says. “The abnormality prevents the brainstem from reacting to the asphyxial challenge and awakening.”

The researchers believe these findings support that sudden unexplained death in babies is associated with inherent exposures, and that not all babies who die in endangered slumber surroundings are standard.

“Surely, there are dangerous sleep environments that could cause any infant to expire, like entrapment in the crib, but if it is only sleeping face down, the infant who dies may have an inherent brainstem exposure,” says Kinney. “We must discover methods to analyze for this inherent exposure in living infants and then to treat it. Our team is focused now upon developing this type of evaluation and treatment.

“Safe slumber practices certainly stay significant, so these babies aren’t get in a potentially asphyxiating position they can’t react to,” she adds.