As New Studies Emerge, Debate Still Surrounds Shaken Baby Syndrome
Defino, Theresa
When he was in medical school 20 years ago in Chicago, pediatric neurologist Joseph Scheller, MD, learned about shaken baby syndrome (SBS). He was taught to recognize what the National Center on Shaken Baby Syndrome calls the classic triad of subdural hematoma, brain swelling, and retinal hemorrhages.
But when faced with his first possible case of SBS while completing his specialty neurology training after becoming a pediatrician, Dr. Scheller began to have doubts about the scientific basis for the syndrome. As he cared for the infant, got to know the family, and looked deeper into research on the pathophysiology of brain trauma, he became convinced there were other reasonable explanations for the child’s injuries.
And Dr. Scheller, now in practice with Children’s National Medical Center in Washington, DC, says his doubts have intensified, fueled by his clinical experiences and a steady stream of articles in the medical literature questioning the validity of SBS.
It is a house of cards built on nothing, Dr. Scheller says of SBS. I can’t even say, ‘This is SBS, and this is the person that did it,’ because I’m not sure it exists. Every hospital has a child abuse specialist, and they have bought into the idea that if there is no sign of trauma except bleeding in the brain and behind the eyes, then it must be SBS. I am sure there are terrible people and they do terrible things to children. But it never has been shown that shaking can cause these injuries.
CONCEPT OF SBS EMBRACED
The medical establishment continues to embrace the concept of SBS, as it has since the 1980s. SBS has its own ICD-10 code, medical schools include it in the curriculum, and millions of dollars are spent each year on public education to warn parents and caregivers about the dangers of shaking; juries continue to issue child abuse convictions. But critics of SBS argue that many of the basic questions that arose almost immediately after the syndrome was introduced have remained unanswered and the controversy over SBS, rather than dying down, has intensified.
The most extensive research on the biomechanics of shaking and SBS has been conducted by a research team at the University of Pennsylvania in Philadelphia. Using a lifelike doll simulating a one-and-a-half-month-old baby, the group concluded in a paper published last July that falls from moderate heights and impacts with surfaces produce considerably higher head decelerations than vigorous shaking associated with SBS (J Neurosurg 2003;99:143-150).
The senior researcher on the team, Susan Margulies, PhD, who has been investigating potential mechanisms for SBS since 1987, told Neurology Today that it is premature for SBS to be considered a diagnosis.
Figure. Dr. Susan Ma…
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We have not yet confirmed with objective data that shaking without any impact causes injuries, says Dr. Margulies, Professor of Bioengineering and Director of the Bioengineering Lab. What is missing are studies of repeated low-level acceleration-decelerations, like shaking – without that data we cannot yet interpret doll studies results and predict injuries.
ACCLERATION-DECELERATION STUDIES
This past March, her group published data demonstrating that two rapid acceleration-deceleration events 15 to 20 minutes apart produced more widespread neural injury in neonatal pigs than a single event, but it is not yet known whether increasing the number and frequency of the low-level events to simulate shaking would also exacerbate the injury (J Neurotrauma 2004;3:307-316).
Current views regarding SBS, Dr. Margulies contends, are based on hypotheses rather than supported by objective evidence from immature subjects.
Also, in March, the British Medical Journal (BMJ) published a series of articles questioning the certainty of SBS, including a literature review by Patrick Lantz, MD, Associate Pathology Professor at Wake Forest University School of Medicine in Winston-Salem, NC, and others (BMJ 2004; 328:754-756). The review article focused on a 14-month-old who died after a television set fell on him. His brother was placed in foster care as child abuse was investigated because the baby had perimacular retinal folds coincident with retinal hemorrhages, which a pediatric ophthalmologist who saw the child stated was part of the criteria for SBS.
In his review, Dr. Lantz and his co-authors found that statements in the medical literature that perimacular retinal folds are diagnostic of shaken baby syndrome are not supported by objective scientific evidence. They cite findings from another study that looked at SBS research in general from 1966 to 1998, which uncovered a weak scientific evidence base. Selection bias, inappropriate controls, and the lack of precise criteria for case definition were identified as important problems with the data.
Many studies committed a fallacy of assumption, selecting cases by the presence of the clinical findings that were sought as diagnostically valid, Dr. Lantz and his colleges wrote in the BMJ article. Unsystematic reviews and consensus statements often mingled opinion with facts and added no original supporting evidence.
In an editorial accompanying Dr. Lantz’s study, John Plunkett, MD, a forensic pathologist at Regina Medical Center in Hastings, MN, wrote that it is time to reconsider the diagnostic criteria if not the existence of shaken baby syndrome.
Randell Alexander, MD, PhD, scoffed at such comments. Dr. Alexander, Director of the Center for Child Abuse and Associate Professor of Pediatrics at Morehouse School of Medicine in Atlanta, took issue with Dr. Margulies’ findings, calling her work not up to date. He said the researchers at Brown University have also used a doll to measure head accelerations produced by shaking. This research has not been published.
However, Dr. Alexander, also an advisory board member for the national SBS center, discounted such work, saying, We have all the clinical experience … it does not matter what the biomechanical engineering studies show. He added that there are lots of accused child abusers who have confessed to shaking the child.
HOW SYNDROME WAS DEFINED
Skeptics of SBS say the diagnosis grew out of fundamental misinterpretations of a few short papers that appeared in the late 1960s and early 1970s, including a five-page study about whiplash in adult primates in the Journal of the American Medical Association in 1968. In this study, Ayub Ommaya, MD, a neurosurgeon and former Chief of Neurosurgery at the NIH, and his coauthors, were able to produce head injuries in adult rhesus monkeys who were subjected to forces simulating whiplash in car accidents.
Another paper that is frequently cited as proof of SBS is a two-page report that was published in the BMJ in 1971. Based on a review of two infants, author A. N. Guthkelch stated that it was possible to cause a subdural hematoma in an infant through repeated accelerations and decelerations of an infant’s head, which he called shaken whiplash syndrome. A year later, John Caffey, MD, reached the same conclusion, and he also included descriptions from a nurse who worked in a neonatal unit with a high number of deaths and infants with mental handicaps, who admitted to shaking crying infants to make them stop.
Those who extrapolated the adult monkey research to human infants did not appreciate how much acceleration was necessary to cause head injuries, and what kinds of head injuries were caused, said Ronald Uscinski, MD, a neurosurgeon on the faculty of Georgetown University and George Washington University in Washington, DC, who studied under Dr. Ommaya. Shaken baby syndrome was assumed to be true without any proof, Dr. Uscinski added.
Drs. Uscinski and Ommaya and Larry Thibault, ScD, who was a co-author with Dr. Margulies on the first study using dolls that was published in 1987, all wrote a letter that was published in a medical journal in March. Writing in response to the July 2003 study, they questioned why shaking is still invoked as a cause of intracranial injuries in infants, given Dr. Margulies’ findings over the years.
His concerns about SBS were heightened after he was consulted in 1996 on the British nanny child abuse case involving the death of an eight-month-old baby in Boston, Dr. Uscinski said. The nanny was charged with first-degree murder, and convicted of second-degree, but the judge reduced that to involuntary manslaughter. His ruling was upheld by the Massachusetts Supreme Court.
Drs. Uscinski and Ommaya testified that they believed the baby died of an old injury that rebled, pointing to evidence of old wrist and skull fractures.
Those who question the validity of SBS appear as paid expert witnesses for the defense in criminal cases, Dr. Alexander charged. However, Dr. Alexander has also testified, often called by the prosecution in child abuse cases, and has also been paid for his time, he said. Dr. Margulies said she has never testified in an SBS case.
Figure. Dr. Ronald U…
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CONSIDER ALL POSSIBILITIES
The treatment for SBS is the same as for any closed head injury. But because the diagnosis is fraught with legal and emotional import, Dr. Uscinski and others say it is vital to carefully consider all possibilities with an infant or child who has injuries considered typical of SBS.
Don’t just look in the eyes to confirm child abuse, he said. Look whenever you can. Also, at least consider the possibility that some people are telling the truth. Logically, must all unexplained injuries be assumed to be abuse? The most important diagnostic tool the physician, any physician, has is the ability to take a history. If we throw that out, and in all my years of practice, this child abuse business is the only instance where this is deliberately done, we have chaos – misdiagnosis, breaking up innocent families, and the presumption of guilt over innocence.
When you are making a diagnosis that has legal repercussions, please start to understand injury mechanisms, Dr. Plunkett told Neurology Today. From what we know today, SBS is extremely unlikely to exist. There is no evidence that we can find that shaking causes the injuries that have been ascribed to it.
ARTICLE IN BRIEF
✓ A series of journal articles in the last few months has reignited debate about the scientific evidence supporting the diagnosis of shaken baby syndrome nearly 30 years after it was first described in the medical literature.
REFERENCES
• Prange MT, Coats B, Duhaime A, Marguiles SS. Anthropomorphic simulations of falls, shakes, and inflicted impacts in infants. J Neurosurg 2003;99:143-150.
• Raghupathi R, Mehr MF, Helfaer MA, Marguiles SS. Traumatic axonal injury is exacerbated following repetitive closed head injury in the neonatal pig. J Neurotrauma 2004;3:307-316.
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