Although infants and young children do sustain accidental head injuries, in most cases, minor and mild head trauma symptoms are transient. An accidental head injury usually has an outward sign such as a bump, goose-egg, bruising or swelling, which is caused by the head striking an object or surface. Non-accidental head injuries- perhaps the euphemistic term for child abuse- are often not outwardly visible. They are usually caused by the violent shaking of an infant or very young child, which can result in brain damage or death. There has been recent renewed interest in Shaken Baby Syndrome (SBS), as ihas been reported that many cases may be undetected or under-acknowledged (Sydney Morning Herald, 9/18/09).
Studies suggest that approximately 1500 cases of SBS occur in the United States each year. The majority of children are under one year of age, though cases have been reported in the 2-5 year age group as well. An infant's brain is vulnerable to shaking due to the immature protective coating of brain cells and the sheath surrounding it. The classic "contre-coup" brain injury is exemplified in SBS. The primary impact of the brain hitting the skull is followed by a second force of the brain rocketing to the opposite side. The secondary point of impact (contre-coup) delivers a more severe blow. With multiple rounds of forceful shaking, the brain hits the skull repeatedly. There is also a rotational force of the brain causing a shearing of brain cells (both at higher and lower centers of the brain). As the network of blood vessels are still immature under the dura (brain sheath covering), they easily rupture and cause subdural hematomas. These hematomas are readily seen on CT scan or MRI. Neurological examination commonly reveals hemorrhaging blood vessels in the eye (retina). When external injuries (e.g. limb injuries) are absent, the presence of retinal hemorrhages may raise the red flag of SBS, but does not conclusively prove it. Retinal hemorrhages can arise from accidental trauma, arterio-venous malformations, and spontaneous subarachnoid bleeds. History, and a bit of detective work, are often needed to confirm the diagnosis.
A few years ago, an assistant district attorney requested my input on a case of suspected SBS. A three-year old (not your typical SBS aged child) sustained a brain injury documented on CT scan to both the back and front part of the brain (occipital and frontal subarachnoid hemorrhages). The parents signed sworn depositions that the injury occurred when the child, riding a tricycle, slammed her head into the bumper of the family's large 4x4 truck. There were no broken limbs. Retinal examination revealed some small "old" hemorrhages, that did not coincide with the time frame of the reported injury, yet perhaps significant evidence. I offered a narrative opinion after reviewing numerous records and CT scans . If the child actually hit her head on the large metal bumper, it would have required more significant force. Though she did have a bump on her forehead after the injury, it appeared too small to have resulted from a full frontal impact. The hemorrhages on CT scan were unequal. The larger hemorrhage was in the frontal region. If contre-coup physics are correct, and the child struck the frontal region on the metal bumper first, the smaller hemorrhage should have been in the frontal area and the larger one in the occipital region. On the contrary, a forceful shaking of the head backwards would likely produce a smaller occipital hemorrhage and larger frontal hemorrhage (as the brain rockets forward on secondary impact).
I concluded that the child's injuries were likely not due to hitting the bumper, but more consistent with a contre-coup SBS. My report was read aloud in the court though I was not present during the proceedings. The assistant DA called me with interesting news. When my report was concluded, the child's mother began to cry and yelled at her husband that she knew they would "get caught". I wish I could say I shared the assistant DA's enthusiasm for the confession and conviction. Yes, the child would now be remanded to foster care, and hopefully, placed in a stable and safe environment. Yet, she had sustained permanent brain damage at the hands of her own parents and would have to live with this knowledge. I wondered how many of these children go undetected or simply never reported.
Recently, I have read stories of young, single mothers whose babies died or were permanently brain injured by angry boyfriends. This is consistent with the statistics. Typically, males (husbands or boyfriends) are the perpetrators who become easily frustrated and angry with a baby's only form of communication, crying, and shake the children in an attempt to quiet them. Some mothers are also guilty of this behavior, but to a lesser degree.
Some intiative actions aimed at reducing this problem are raising public awareness of SBS and offering young parents child rearing and anger management classes.
Though this is speculative, some children with learning disabilities, neurodevelopmental delays and perhaps a subset of those with ADHD, may have sustained unreported SBS. In the future, a greater understanding of this public health issue may be gained through research and more accurate reporting of SBS.
So what about Uncle Harry who visits the new baby and loves to play "toss the kid" in the air? Most authorities agree that knee bouncing or lifting the baby gently in the air is fine. Common sense is the rule of thumb. I have to wonder, however, about the grey area between the gentle lifting and SBS, particularly during the first 18 months of life. If there is mounting concern internationally that many cases of SBS are under-detected (due to the fact that symptoms of lethargy and seizures can mirror other clinical conditions), vigilance (not hysteria) is appropriate and warranted. We should encourage gentle knee bouncing and discourage any behavior that is contra-coo.
Peter B. Sorman, PhD, ABN
Board Certified Clinical Neuropsychologist
American Board of Professional Neuropsychology
Thanks Dr. Sorman for a great article, as always.
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