Criteria for Shaken Baby Syndrome Questioned

From Medscape Medical News

Laurie Barclay, MD

Authors and Disclosures

March 26, 2004 — The accepted criteria for eye injury and other findings of shaken baby syndrome are questioned in a case report, editorial, clinical review, and letters published in the March 27 issue of the British Medical Journal. The authors raise serious doubts about the validity of using “definitive” criteria such as perimacular retinal folds to diagnose child abuse.

“If you read the medical literature, certain eye findings have been considered diagnostic for shaken baby syndrome,” Patrick E. Lantz, MD, a forensic pathologist at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina, and lead author of the evidence-based case report, says in a news release. “This isn’t supported by objective scientific evidence and could result in innocent caregivers going to jail.”

The authors describe a 14-month-old child who died with perimacular retinal folds, a buckling of the retina reported in shaken baby syndrome, and other characteristic eye injuries after the father reported that a television set had fallen on the child’s head. He said he was in the next room when he heard a loud noise, and he then found the child on the floor with the TV covering the right side of the head and anterior chest.

Cranial computed tomography showed diffuse cerebral edema, a subdural hematoma over the frontal convexities, a left-sided skull fracture with underlying contusions, and a rightward midline shift. Ophthalmological evaluation showed bilateral dot and blot intraretinal hemorrhages, preretinal hemorrhages, and perimacular retinal folds.

“We found that the eye findings in this case were caused by an accident,” Dr. Lantz says. “But when you read the current medical literature, the presence of perimacular retinal folds and hemorrhages in a young child with a serious head injury are considered diagnostic for shaken baby syndrome and cannot be from anything else. When physicians read that, they may stop investigating other potential causes, which could have serious consequences.”

At autopsy, there was no evidence of direct trauma to the orbits or eyes. Findings were prominent bilateral scalp contusions with soft tissue and intramuscular hemorrhage, symmetrical parietal skull fractures with coronal sutural diastasis, lacerated dura mater with extrusion of brain and blood, bilateral subdural and subarachnoid hemorrhages, a thin epidural hematoma, bilateral cortical contusions, severe cerebral edema, and diffuse anoxic-ischemic injury. In the optic nerve sheaths, subdural hemorrhages were more prominent than subarachnoid hemorrhage, and both eyes had extensive retinal hemorrhages, perimacular retinal folds, retinoschisis, and peripapillary intrascleral hemorrhages.

Because of the perimacular retinal folds and hemorrhages, Child Protective Services suspected child abuse and removed a three-year-old sibling from the home, even though Dr. Lantz’ investigation found no indication of child abuse other than the eye findings. Further investigation by the police, a child abuse specialist, and a medical examiner corroborated the father’s report, and the sibling was returned to the care of the parents.

“Until good scientific evidence is available, we urge caution in interpreting eye findings out of context,” Dr. Lantz says.

The authors also reviewed published reports about perimacular retinal folds, and they found that the condition has been reported in cases of shaken baby syndrome. However, no studies have determined whether the condition is also present in accidental head trauma in young children.

“Statements in the medical literature indicate that perimacular retinal folds result from the movement of the gel within the eye when an infant or young child is shaken, and that they have no other cause in young children with head injuries,” Dr. Lantz says. “But our literature review showed that this conclusion is not based on scientifically valid comparative or experimental studies.”

An accompanying letter describes a database collected for more than five years of documented Scottish cases of suspected nonaccidental head injury diagnosed after a multiagency assessment, and including cases with confessions and criminal convictions. The investigators documented four predominant types of injury.

Hyperacute encephalopathy, or cervicomedullary syndrome, accounted for 6% of all cases. This injury results from extreme “whiplash” forces breaking the neck, or brain stem. Acute encephalopathy, occurring in 53% of cases, is characterized by depressed consciousness, raised intracranial pressure, seizures, apnea, hypotonia or decerebration, anemia, shock, bilateral subdural hematomas, and widespread hemorrhagic retinopathy. Other nonaccidental injuries may be associated with this repetitive, rotational injury referred to as the classic shaken baby syndrome.

A subacute nonencephalopathic presentation occurs in 19% of cases, with less intense brain injury and better outcome. Chronic extracerebral presentation, accounting for 22% of cases, occurs in children a few months old who present with an isolated chronic subdural hemorrhage. Signs include rapidly expanding head circumference, raised intracranial pressure, irritability, vomiting, failure to thrive, hypotonia, and seizures.

“We postulate that a spectrum of clinical features is related to the intensity and type of injury in babies with inflicted brain injury, reconciling the clinical and neuropathological findings,” write Robert A. Minus and Anthony Busuttil, from the University Edinburgh in Scotland. “The generic term non-accidental head injury or inflicted traumatic brain injury should be used in preference to shaken baby syndrome, which implies a specific mechanism of injury.”

They report no competing interests.

Another letter, by James LeFanu, from Mawbey Brough Health Centre, and Rioch Edwards-Brown, director of The Five Percenters, both in London, U.K., suggests that trivial falls and other minor injuries can give rise to the allegedly characteristic signs of shaken baby syndrome.

Minor trauma (37% of cases), such as a fall from a bed or sofa, can result in immediate loss of consciousness or delayed presentation of an acute subdural and retinal hemorrhages. Birth injury (29% of cases) can present chronically with nonspecific symptoms, such as vomiting and lethargy, until computed tomography shows a chronic subdural hemorrhage. Respiratory arrest (22% of cases), often followed by resuscitation attempts, may result in subdural and retinal hemorrhages.

“These three patterns of clinical events — in the absence of other circumstantial evidence for non-accidental injury — offer a more credible explanation than shaken baby syndrome for the presence of subdural and retinal hemorrhages,” the authors write. “Shaking has never been directly observed or proved to cause such injuries but is rather an inference based on (contested) theories of biomechanics.”

Ms. Edwards-Brown is director of a voluntary organization providing advice, information, and support to parents who state that they have been wrongly accused of shaken baby syndrome. Neither she nor any individual in the organization report any competing financial interest.

In an accompanying editorial, J. F. Geddes, formerly from Queen Mary, University of London in the U.K., and J. Plunkett, from Regina Medical Center in Hastings, Minnesota, refer to the Web site of the American Academy of Ophthalmology, which states that if the retinal hemorrhages have specific characteristics “shaking injury can be diagnosed with confidence regardless of other circumstances.”

Drs. Geddes and Plunkett challenge that statement in light of the case report by Lantz and colleagues and other reports revealing “major shortcomings in the literature relating to a fieldin which the opportunity for scientific experimentation and controlled trials does not exist, but in which much may rest on interpretation of the medical evidence.” They note that criticisms of lack of case definition and proper controls can apply to the whole literature on child abuse as well as to the more specific literature on shaken baby syndrome.

“If the issues are much less certain than we have been taught to believe, then to admit uncertainty sometimes would be appropriate for experts,” the editorialists write. “Doing so may make prosecution more difficult, but a natural desire to protect children should not lead anyone to proffer opinions unsupported by good quality science. We need to reconsider the diagnostic criteria, if not the existence, of shaken baby syndrome.”

Both editorialists report that they have given evidence in criminal child abuse cases for both the prosecution and the defense.

In a second editorial, Brian Harding, from Great Ormond Street Hospital for Children in London, U.K., and colleagues urge physicians to evaluate in detail all of the circumstances surrounding the injury and all pathological features taken together.

In shaken baby syndrome, the combined triad of subdural and retinal hemorrhage with brain damage, together with reconstruction of the mechanism of injury, may allow the conclusion that undue force has been applied. Other confirmatory evidence may include damage to the neck or spinal cord, the presence of gripping injuries, and inflicted extracranial injuries.

“Clearly, if ‘gentle’ shaking were capable of causing fatal injury, such events would be an everyday occurrence,” they write. “Although neuropathological findings in the brains of infants dying of non-traumatic cerebral hypoxia may show intradural hemorrhage evident only at the microscopic level, subdural hemorrhage in shaken baby syndrome is a macroscopic, not a microscopic, finding.”

The editorialists report no competing interests.

BMJ. 2004;328:719-721, 754-756, 766-767

Reviewed by Charlotte E. Grayson, MD

Source:

http://www.medscape.com/viewarticle/472546