Shots - Health Blog
Autopsy Study Provides New Theory On Shaken Baby Syndrome
Findings from a series of autopsies could alter the debate over the controversial diagnosis of shaken baby syndrome.
A new study suggests that babies can die by violent shaking alone — but not in the way doctors have previously thought.
A team of researchers who conducted autopsies on 35 babies in Miami, Dallas and Calgary, Alberta, report that when children die after being violently shaken, they die of neck injuries and not from brain trauma.
Shaken baby syndrome is commonly invoked to prosecute child abuse. But growing numbers of medical experts — particularly forensic pathologists — have raised doubts about the diagnosis.
Skeptics question whether it's possible to shake a baby so violently that the child dies from brain injury but without other visible marks or trauma to the neck and spine.
The confusion over the science sometimes results in the conviction of innocent parents and prison. A series of investigative reports called Post Mortem: Child Cases, this week by NPR, PBS Frontline and ProPublica told the stories of the wrongly convicted and looked at the case of Ernie Lopez, who is serving a 60-year prison sentence in Texas.
The authors of the new research did something novel. They looked at a baby's nerve roots. Those are hard to observe, because they are protected by the bone and spine. But by looking, the scientists say they found injuries that no one had observed before. "We contend that up until now, 'neck injuries' have not been seen, not because they were not present, but rather because the appropriate anatomical structures were not dissected," writes lead author Dr. Evan Matshes, a medical examiner in Calgary.
Babies breathe primarily by expanding their bellies. To do this, the diaphragm, the muscle at the base of the lungs, moves to create more room for the lungs to expand. (Adults have an additional way to support breathing: By using chest muscles to to move the rib cage.)
The researchers found that when babies are shaken, the nerve roots get injured and that knocks out the diaphragm. That leads to the brain injuries that are seen in children who are shaken — but it's original injury to those nerves in the neck that caused the death, not the brain injury, according to the new research.
The new findings split a lot of the difference between the warring camps on shaken baby syndrome. For supporters, there's evidence that shaking alone can lead to a baby's death. But it also says skeptics were right to suggest it's not the head injury that causes death and that shaking deaths are likely rare.
The research got an endorsement from the man who is considered the discoverer of shaken baby syndrome. Pediatric neurosurgeon Norman Guthkelch was the first — forty years ago — to connect head injuries in young children to violent shaking. Guthkelch told NPR in an email that the new research is a "most important contribution to understanding" of shaken baby syndrome, adding:
I have little doubt that it will be confirmed by other workers in due course. It will then be possible to say with confidence that if the lesion they described is present, significant shaking occurred--and if not, not. It also explains why in SBS cases a fatal loss of vital functions may not be associated with the degree of traumatic brain damage that one would expect.
In an interview earlier this week with NPR, Guthkelch spoke out for the first time about his worries that doctors and other medical experts are too quick to diagnose shaken baby syndrome when there's suspicion of child abuse, without considering other possibilities.
It's not clear whether forensic pathologists will embrace the findings. For one thing, it's hard work to get at those nerve roots as Matshes and his colleagues did in their small study.
There are extra, time-consuming steps that have to be taken at an autopsy. The spinal column has to be placed in formaldehyde for up to a month in order for the bone to soften before the pathologist can even get at those roots. But the new paper says that's an commitment of time can help pathologist get at the truth of how a baby died.