August 2009 | Back to Table of Contents

Face to Face

Challenging an Assumption

A pathologist questions shaken baby syndrome.

By Kate Ledger

For John Plunkett, M.D., the case in 1986 that would put a new spin on his career was not unlike others he’d seen before. A general and forensic pathologist who occasionally consulted for attorneys, Plunkett was asked to review the post-mortem findings following the death of an 18-month-old girl. According to the mother, the baby had climbed onto the arm of a couch to reach for a figurine on a shelf, then fell, hitting her head on the linoleum floor. But physicians at Minneapolis Children’s Hospital and the Hennepin County Medical Examiner didn’t believe the story. The baby showed bleeding inside the dura within the skull, hemorrhaging of the blood vessels in the retinas, and altered function in the brain. Those who’d examined her both before and after she died saw no evidence of impact on her head. “They were convinced this could only be inflicted trauma,” Plunkett recalls. What they believed, based on the specific injuries, was that the mother had shaken her baby to death.

As the mother went to trial, Plunkett began to wonder about the symptoms: Where was the evidence that subdural bleeding, retinal hemorrhaging, and brain swelling—considered the classic triad of signs pointing to a shaken baby—added up to murder? His questioning of the post-mortem findings spurred him onto a new tack of research, and he began to investigate the concept of “shaken baby syndrome.” What he’s found over the years has turned him into a controversial figure in cases of alleged child abuse. Today, physicians in pediatrics and pathology have wide-ranging opinions of the widely published pathologist, now retired from his hospital work, as he continues to consult, write, and speak on infant head injury. “He’s both revered and reviled,” says pathologist Susan Roe, M.D., who works for Regina Medical Center and serves as a forensic pathologist for the Minnesota Regional Medical Examiner’s office. But Plunkett has remained emphatic about his belief: “You can’t shake a baby to death.”

Parsing the Evidence John Jerome Plunkett was born in St. Paul and lived first in Highland Park and then in the middle- and working-class Midway neighborhood. His father was a lawyer who spent almost his entire career as a Ramsey County District Judge. His uncles were also attorneys, and his brothers and cousins went into the field as well. “I grew up with a real love for the law,”

Plunkett acknowledges. But while completing a bachelor’s degree in history and chemistry at the University of Minnesota, he found himself drawn to medicine instead.

After earning a medical degree in 1972, he realized he was interested most of all in asking certain types of questions about patient cases, which led him to pathology and “the most scientific part of medicine.” After an internship and pathology residency at St. Paul-Ramsey Medical Center (later to become Regions Hospital), he completed a forensic fellowship at the Hennepin County Medical Examiner’s Office. His plan was to be “a general pathologist and a medical educator first and a forensic pathologist second.”

True to his career goals, Plunkett worked as a pathologist and director of education at what is now Regina Medical Center in Hastings and spent nearly a decade as Hennepin County’s deputy medical examiner. As a forensic pathologist, his findings were often used in court, placing him at the intersection of science and the law, something he found “very appealing.” One trait Plunkett came to be known for was his willingness to wonder aloud. Pathologist Janice Ophoven, M.D., who trained concurrently with Plunkett and worked with him at the medical examiner’s office, says he was always comfortable questioning. “He would always ask, ‘What’s your proof for this?’ and he wasn’t afraid to challenge people.” Plunkett did just that in the 1986 case in which the mother was convicted of second-degree murder. When Plunkett looked at autopsy photographs of the 18-month-old girl, he discerned a bruise on the skull where others had seen none. “I said, ‘Wait a second. Why couldn’t this impact injury have caused what we’re seeing in the brain?’” he recalls. The response he received from other physicians was that short-distance falls can’t cause serious injury or death in an infant. But Plunkett was skeptical. He went back to the literature, looking for evidence. Two journal articles, one American and one British, published in the early 1970s had established the diagnostic paradigm that would come to be known as shaken baby syndrome. In the absence of any other signs of trauma, the papers stated, subdural hematoma, retinal hemorrhaging, and brain swelling were signs of forceful shaking. Furthermore, the papers stated, no other kind of trauma could cause the three symptoms. Digging into case studies of accidental deaths, however, Plunkett found incidents that suggested otherwise. In 2001, he published an article in the American Journal of Forensic Medicine and Pathology documenting 18 confirmed cases in which infants and young children died from falls of less than 10 feet. “So clearly it can happen,” he says. At the same time, he began looking closely at literature from the automotive industry, in particular, studies of child crash-test dummies, where researchers had calculated the effects of acceleration and deceleration on the human body. With calculations of cycles per second (human hands can only shake a baby at about four cycles per second) and how far the head moves, Plunkett explains, “using just plain old trigonometry you can calculate the acceleration [of the head], the change in velocity over time.” Comparing that figure to known injury thresholds based on experimental results from animal studies, cadaver studies, or reconstruction of real-life accidents, it’s possible to determine the type of forces that would cause injury. Even though the forces involved in shaking could cause an injury such as whiplash, Plunkett states, “they’re nowhere even near the threshold required to cause brain injury.”

He wasn’t alone in wondering about shaken baby syndrome. Across the country, a handful of researchers had begun questioning it. One was pediatric neurosurgeon Ann-Christine Duhaime, M.D., now at Dartmouth-Hitchcock Medical Center, whose research involved modeling head trauma. Her studies showed that shaking would cause less than one-tenth the amount of force needed to inflict injury. To Plunkett’s thinking, a variety of other scenarios could result in the classic triad of symptoms. He suggests meningitis, encephalitis, or chronic subdural hematomas, for instance, a yet- undiagnosed inborn error of metabolism or “some natural disease.” In addition to writing journal articles questioning the classic triad and presenting his findings at conferences, Plunkett began testifying in court cases, opposing prosecution that used it to get murder convictions. What he has emphasized is that the medical community still lacks sufficient proof for its definition of shaken baby syndrome. In the absence of other injuries—when there are no head bruises or bumps, and no signs of old broken bones or bruises on other parts of a baby’s body—the classic triad does not mean shaking necessarily has taken place. He believes that the seminal papers from the 1970s misinterpreted the original research results of Ayub Ommaya, M.D., a neurosurgeon and biomechanical engineer, who had at one time been head of the neurosciences branch of the National Institutes of Health. Over the years, physicians’ refusal to re-examine the tenets about shaking in babies with no other signs of injury, has undoubtedly led to the conviction of innocent citizens. “People just believed this stuff for so long,” Plunkett says, “it took on a life of its own.” A New Look at the Issue Ophoven, who is now assistant medical examiner for St. Louis County and a specialist in child abuse and injury, remembers being put off at first when Plunkett began questioning shaken baby syndrome. Then, in the late 1990s, as more papers appeared questioning the symptoms, she began to review the literature and changed her mind. “The fundamental evidence has never been scientifically validated,” she says. Since testifying for the defense in cases where no signs of abuse are present but the baby shows the classic triad, even physicians have called her names, from “defense whore” to “wicked.” Ophoven adds, “John has been called worse.” Plunkett’s influence may not have pushed the majority of forensic pathologists to become defense advocates. But some may now be more conservative in their judgment, speculates Roe. “John has been one of the key people getting our whole community to relook at this whole issue,” she says. Many forensic pathologists might be more inclined today to call a case with no other evidence “undetermined” rather than label it homicide, she adds. But pediatricians, many of whom say they like Plunkett personally, having met him in court or at conferences, have taken issue with his findings. Some have questioned the math in the biomechanical engineering studies. Others have looked closely at studies such as Duhaime’s and critiqued the modeling of a baby’s brain, pointing out that no material exists to replicate a newborn’s skull. Although many physicians concur that it’s positive to be asking questions about the validity of the diagnosis, ultimately “there is no credible medical evidence to support the notion that shaking does not cause these injuries,” says Robert Block, M.D., former chair of the American Academy of Pediatrics’ Committee on Child Abuse and Neglect. Block co-

authored a policy statement that was issued earlier this year by the AAP, formally changing the name shaken baby syndrome to abusive head trauma. (For public health messages to families, the term shaken baby syndrome will still be used.) The goal of the paper, says Block, was to shift the focus to the injuries and the incidence of abuse and away from the debate over whether shaking is the key mechanism. Without a doubt, the debate has prompted a closer look at the classic triad. In the last decade, notes pediatrician Rich Kaplan, M.D., of Children’s Hospital and Clinics of Minnesota and the University of Minnesota, research has offered refined descriptions of some of the symptoms associated with shaking. “For instance, there’s greater understanding of retinal hemorrhaging, and today, we know that a small amount of bleeding in the back of the retina can be caused by something other than abuse.” Kaplan adds that pediatricians have become better informed in the last several years and now consider a wide range of possible causes; but he still worries that the opposite is of greater concern: Pediatricians and other health care providers are still not seeing abuse when it occurs. Even so, Plunkett maintains that the triad continues to be used so vigorously by prosecutors that an accused person faces an uphill battle. “You basically have to prove your innocence,” he says, estimating that the number of people inappropriately convicted might be in the thousands. Even when caregivers are on record for having “confessed,” he points out, their acknowledgment of “shaking” has referred to the moments of reviving a baby who was already unconscious or even jostling a baby on a knee. What’s given him hope lately is that in the United Kingdom and Canada, old cases of abuse have recently been reopened and reinvestigated with new awareness of the controversy about shaken baby symptoms. In Britain, for instance, if the only findings are subdural hematoma, retinal bleeding, and brain swelling—with no other signs of trauma, no history of harm, and no witnesses—they are no longer enough to bring charges. Plunkett believes that the United States is still far off in setting justice straight, but he hopes the medical world will eventually take note of what’s “really a paradigm change” in approaching infant injury evaluation. “At the end of the day,” he says, “the default diagnosis is not abuse, it is ‘I don’t know.’” MM

Kate Ledger is a freelance writer in St. Paul, Minnesota, and a frequent contributor to Minnesota Medicine.

January 2010 | Back to Table of Contents

Letters

Evidence Outweighs Belief

Congratulations on the publication of a significant and meaningful cover story featuring Dr. David McCollum and focusing on the hidden costs of abuse and neglect (August, p. 26). Articles by Dr. Therese Zink (p. 32), Dr. Amy Walsh (p. 37), and Susan McCormick Hadley (p. 41) add to your appropriate emphasis on the health costs of violence and abuse.

Unfortunately, your feature on Dr. John Plunkett falls short of the high caliber of the other reports. One of our International Advisory Board members, Dr. Robert Block, spent a significant amount of time talking with reporter Kate Ledger, who chose to condense their long conversation into a single quote and a statement. The result is that the article is misleading and misrepresents the spectrum of fact and medical opinion on the issue of shaken babies and abusive head trauma.

Dr. Plunkett is well-known to the medical experts who frequently find their medical opinions challenged by him as he tours the United States as a hired defense witness. He remains “emphatic,” says Ms. Ledger, “about his belief: You can’t shake a baby to death.”

While he is obviously entitled to his belief as a physician and defense witness, he is also obligated to study, interpret, and acknowledge the myriad solid medical evidence that does not support his belief. The article cites Dr. Plunkett’s paper from 2001, correctly stating that he documented 18 confirmed cases of death from falls of less than 10 feet. But the article does not include the fact that these few cases were culled from more than 75,000 reports of playground injuries severe enough to be reported, nor does it include the fact that there were no infant deaths, and only five of the children were between the ages of 12 and 24 months. Most of the deaths were not what most people would call “short falls,” as they involved playground equipment such as moving swings. His article actually confirms that deaths from short falls among infants and young children are extremely rare. A more recent peer-reviewed study finds the incidence of death among young children experiencing short falls is in the range of 0.5 per 1 million.

Ms. Ledger reports that “Plunkett believes that the United States is still far off in setting justice straight.” What a shame it would be for the memory of dead babies and for the parents of babies killed by other caregivers if “setting justice straight” meant accepting a minority opinion totally without biomechanical, epidemiologic, or biological confirmation.

We find it concerning that the author failed to cite the enormous body of peer-reviewed medical literature from countries and centers around the world that consistently and repeatedly support the concept of shaken baby syndrome and has led to the formation of statements to that effect by multiple major medical organizations, not the least of which is the American Academy of Pediatrics.1-14

Randell Alexander, M.D., Ph.D. Ronald G. Barr, MDCM, FRCPC Robert Block, M.D., FAAP Mary Case, M.D. David L. Chadwick, M.D. Brian Holmgren, J.D. Carole Jenny, M.D., MBA John M. Leventhal, M.D. Alex Levin, M.D., MHSc Robert Reece, M.D. Philip Wheeler, DCI Marilyn Barr, executive director International Advisory Board National Center on Shaken Baby Syndrome

Abbreviated Reference List 1. American Academy of Pediatrics Committee on Child Abuse and Neglect. Shaken baby syndrome: rotational cranial injuries-technical report. Pediatrics. 2001;108(1):206-10. 2. Barlow KM, Milne S, Aitken K, Minns RA. A retrospective epidemiological analysis of non-accidental head injury in children in Scotland over a 15 year period. Scot Med J. 1998;43:112-4. 3. Bechtel K, Stoessel K, Leventhal J, et al. Characteristics that distinguish accidental from abusive injury in hospitalized young children with head trauma. Pediatrics. 2004;114:165-8. 4. Block RW. Child abuse—controversies and imposters. Curr Probl Pediatr. 1999;29:253-72. 5. Case ME, Graham MA, Handy TO, Jentzen JM, Monteleone JA. National Association of Medical Examiners Ad Hoc Committee on Shaken Baby Syndrome. Position paper on fatal abusive head injuries in infants and young children. Am J Forensic Med Pathol. 2001;22(2):112-22. 6. Chadwick DL, Bertocci G, Castillo E, et al. Annual risk of death resulting from short falls among young children: less than 1 in 1 million. Pediatrics. 2008;121(6):1213-24. 7. Christian CW, Block R. Committee on Child Abuse and Neglect. American Academy of Pediatrics. Pediatrics. 2009 May;123(5):1409-11. 8. Jaspan T. Current controversies in the interpretation of non-accidental head injury. Pediatr Radiol. 2008;38(S3):S378-87. 9. Keenan HT, Runyan DK, Marshall SW, et al. A population-based study of inflicted traumatic brain injury in young children. JAMA. 2003;290:621-6. 10. Kivlin JD, Simons KB, Lazoritz S, Ruttum MS. Shaken baby syndrome. Ophthalmology. 2000;107:1246-54. 11. Minns RA, Brown JK. Shaking and other non-accidental head injuries in children. London: MacKeith Press, 2005. 12. Morad Y, Kim YM, Armstrong DC, Huyer D, Mian M, Levin AV. Correlation between retinal abnormalities and intracranial abnormalities in the shaken baby syndrome. Amer J Ophthalmol. 2002;134:354-9. 13. Punt J, Bonshek RE, Jaspan T, et al. The “unified hypothesis” of Geddes et al. is not supported by the data. Pediatr Rehabil. 2004;7:173-84. 14. Starling SP, Patel S, Burke BL, et al. Analysis of perpetrator admissions to inflicted traumatic brain injury in children. Arch Pediatr Adolesc Med. 2004;158:454-8.

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February 2010

Letters to the Editor

Flawed Logic

I am writing in response to the letter published in your January 2010 issue (“Evidence Outweighs Belief,” p. 5), which was critical of Dr. John Plunkett’s views on the various inconsistencies related to so-called shaken baby syndrome (SBS) (see article on Dr. Plunkett in the August 2009 issue, p. 22).* There are many physicians who, after serious consideration and research, are quite certain that SBS is invalid when applied to healthy children.

Short falls do cause serious injury, and citing the infrequency of serious injury from such falls is a deception. Children who land on their head after falling from 3 feet are moving at 13.5 feet/second and hit the ground with a force of 259 pounds. When the head hits a hard floor, 130g of deceleration (130 times the force of gravity where g is acceleration due to gravity) are applied to the head. This is above the known threshold for injury, which is about 50g. Add 18 inches to the distance of a fall (a baby standing on a counter), and the head would be traveling at 17 feet/second and generating a force of 180g on impact.1 It is clear that there is substantial force involved in short falls and that as the fall distance increases, the risk of injury increases accordingly.

It is worth noting that a child who lands on his head after falling from those heights will be injured and will need to be seen in an emergency department. Although such falls are infrequent, infrequency is not a basis for discounting the possibility of accidental trauma and, thus, not the basis for discounting the accounts of apparently reliable caregivers.

The deception perpetrated by the signers of this letter equates infrequency of a serious fall with the improbability of an accidental fall. This is both a logic flaw and an intentional disregard of the physics of falling. Although the fact that one in a million falls will result in a serious head injury may be true, it means that if a million children have accidental falls in a day, then there will be a serious head injury from at least one of those falls every day. We know that number is higher based on experience in emergency medicine. On the premise that only a small fraction of accidental falls are serious, the signers of this critique would discount the history of the caregiver and conclude that he or she has abused the child. In the absence of impact trauma to the head, intentional injury would be the presumption and SBS the default diagnosis.

Reliable studies using sophisticated biofidelic instrumented crash dummies have shown shaking can generate at most about 10g of force.2,3 Bandak has shown beyond dispute that neck damage will result before brain injury can occur with shaking.4

In every case in which shaking is alleged without neck injury, which is virtually every case, shaking can be ruled out as the cause of primary intracranial trauma.

Clinically, the misconception that common short falls do not cause serious injury was studied by Greenes and Schutzman. In an article published in the Annals of Emergency Medicine in 1997, they report that among children who fell less than 3 feet and were brought to an emergency department by a concerned parent, approximately 18 percent had severe intracranial trauma or skull fracture.5 In another study published in 1998, the authors found 18 percent of children with significant head injury, primarily fractures, were without neurologic symptoms or evidence of external trauma.6

The use of retinal hemorrhage to diagnose SBS is flawed as well. In 1984, Aoki found retinal hemorrhage in 100 percent of children with subdural hematomas from impact trauma with no shaking.7

The frequency of perinatal subdural hematoma evolving into chronic subdural hematoma (CSDH), with its inherent complications, while infrequent, is similarly discounted.8 A 0.5 percent complication rate in the United States alone will yield 2,000 cases of CSDH presenting as neuropathic events in infants, which invariably are diagnosed as abuse.

Furthermore, the scope of the research that led to the creation of SBS has been shown to be flawed by Donohoe. In an article published in the American Journal of Forensic Pathology in 2003, he wrote that there was inadequate scientific evidence to come to “a firm conclusion on most matters pertaining to SBS,” and he called for properly controlled, prospective trials into SBS. “Without published and replicated studies of that type,” he wrote, “the commonly held opinion that the finding of subdural hematoma and retinal hemorrhage in an infant was strong evidence of SBS was unsustainable, at least from the medical literature.” 9

The investment in maintaining the mythology of SBS is substantial for the signers of this letter and others. Many people are in jail, and many families have been ripped apart based on their efforts. The injustice caused by the application of nonevidence-based theories to prosecute innocent caregivers is real, and many courts in the United States and the government of Canada have acknowledged this.10

I agree with the title given to this critique. The evidence does outweigh belief. But in this case, the evidence trumps the unsupported belief in this improbable and unproven construct of shaking.

Lastly, every physician and law- enforcement professional should be aware that there has never been a witnessed or videotaped incident of shaking a healthy child in which the child was immediately examined and found to have either retinal hemorrhage or subdural hematoma.

Author: Steven Gabaeff, M.D., F.A.A.E.M. Emergency and Clinical Forensic Medicine Sacramento, California

Cosigners: Thomas L. Bohan, Ph.D. (physics), J.D. President, American Academy of Forensic Sciences (as an individual) Marvin Miller, M.D. Professor of Pediatrics and Ob/Gyn Affiliated Professor of Biomedical Engineering, Wright State University Boonshoft School of Medicine Dayton, Ohio Horace Gardner, M.D. Ophthalmology Manitou Springs, Colorado Robert K. Rothfeder, M.D. Emergency Physician Salt Lake City, Utah Joseph Scheller, M.D. Forensic Pathology Assistant Professor of Paediatrics and Neurology, George Washington University School of Medicine Washington, D.C. David M. Posey, M.D. Glenoaks Pathology Medical Group, Inc. American Autopsy Services, Inc.

References: 1. The chain of physics calculations used is this: Impact velocity, V, resulting from free fall from a

given height, h, is: V = SQRT(2*g*h). Average acceleration at impact, a, occurring over a time, dt, is a = (dV/dt)OR, average acceleration, a, occurring over a stopping distance, d, is: a = V^2/(2*d). For a 3-foot fall (h = 3 feet), V = 13.9 ft/sec. If we pick a reasonable impact duration of 7.5 msec, then: a = (13.9 / 0.0075) = 1,853 ft/sec^2 or 58g and for a velocity of 17 feet/sec then a = (17 / 0.0075) = 2,666 ft/sec^2 or 70g. Another approach is to pick a reasonable stopping distance of 0.5 inches (0.042 ft) then: a = 13.9^2 / (2*0.042) = 2300 ft/sec^2 or 71g at 3 feet and 106g at 4.5 feet. If we split the difference between the two approaches, that is roughly 65g average acceleration at 3 feet and 90g at 4.5 feet. If we assume a triangular force pulse at impact (standard concept), then the peak values are double the average or about 130g peak linear acceleration from 3 feet and 180g at 4.5 feet. The IARV (injury assessment reference value) for the CRABI 6 month ATD is 50g. (Calculations validated by Kirk Thibault.)

2. Commonwealth v Ann Power, 2005. Report to the Middlesex County District Attorney’s Office, Cambridge Massachusetts by Carole Jenny, dated December 29, 2005. Letters 319.

3. Prange MT, Coats B, Duhaime AC, Margulies SS. Anthropomorphic simulations of falls, shakes, and inflicted impacts in infants. J Neurosurg. 2003;99(1):143-50.

4. Bandak FA. Shaken baby syndrome: A biomechanics analysis of injury mechanisms. Forensic Sci Int. 2005;151(1):71–9.

5. Greenes DS, Schutzman SA. Infants with isolated skull fracture: what are their clinical characteristics, and do they require hospitalization? Ann Emerg Med. 1997;30(3):253-9.

6. Greenes DS, Schutzman SA. Occult intracranial injury in infants. Ann Emerg Med. 1998;32(6):680-6.

7. Aoki N, Masuzawa H. Infantile acute subdural hematoma: clinical analysis of 26 cases. J Neurosurg. 1984;61(2):273-80.

8. Rooks VJ, Eaton JP, Ruess L, Petermann GW, Keck-Wherley J, Pedersen RC. Prevalence and evolution of intracranial hemorrhage in asymptomatic term infants. AJNR Am J Neuroradiol. 2008;29(6):1082-9

9. Donohoe M. Evidence-based medicine and shaken baby syndrome, part I: literature review, 1966–1998. Am J Forensic Med Pathol. 2003;24(3):239–42.

10. Cordner S, Ehsani J, Bugeja L, Ibrahim J. Pediatric forensic pathology: limits and controversies. Commissioned by the Inquiry into Pediatric Forensic Pathology, Ontario, Canada; November 28, 2007. Available at: www.goudgeinquiry.ca/policy_research/pdf/Limits_and_Controversies-CORDNER.pdf. Accessed January 11, 2010.