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Shaken baby syndrome
Shaken baby syndrome (SBS) is a form of child abuse that is thought to occur when an abuser violently shakes an infant or small child, creating a whiplash-type motion that causes acceleration-deceleration injuries. The injury is estimated to affect between 1,200 and 1,600 children every year in the USA. A remarkable feature of SBS is the typical lack of external evidence of trauma. The combination of shaking with striking of the infant against a hard object is sometimes termed the shaken impact syndrome.
The concept of SBS was initially described in the early 1970s, based on a theory and a wide variety of circumstances by Dr. John Caffey, a radiologist, as well as Dr. Norman Guthkelch, a neurosurgeon.
SBS, a major cause of mortality in infants, is often fatal and can produce lifelong disability from neurological damage. Up to 50% of deaths related to child abuse are reportedly due to shaken baby syndrome. About 25% to 30% of infant victims with SBS die from their injuries. Nonfatal consequences of SBS include varying degrees of visual impairment (e.g., blindness), motor impairment (e.g. cerebral palsy) and cognitive impairments.
Signs and symptoms
The signs associated with inflicted SBS include retinal hemorrhages, petechiae (small, pinpoint hemorrhages) on the body or face, multiple fractures of the long bones, and subdural hematomas. These signs have evolved through the years as the accepted and recognized signs of child abuse and the shaken baby syndrome. Additional effects of SBS are diffuse axonal injury, oxygen deprivation and swelling of the brain, which can raise intracranial pressure and damage delicate brain tissue.
Most victims of SBS are under one year old. Victims of SBS may display irritability, failure to thrive, alterations in eating patterns, lethargy, vomiting, seizures, bulging or tense fontanels, increased size of the head, altered respirations, and dilated pupils. Medical professionals strongly suspect shaking as the cause of injuries when a baby or small child presents with retinal hemorrhage, fractures, soft tissue injuries or subdural hematoma, that cannot be explained by accidental trauma or other medical conditions. No alternative condition mimics all of the symptoms of SBS exactly, but those that must be ruled out include hydrocephalus, sudden infant death syndrome (SIDS), seizure disorders, and infectious or congenital diseases like meningitis and metabolic disorders.
Fractures of the vertebrae and ribs may also be associated with SBS. Although several bone disorders may also cause increased vulnerability to fractures, they can be distinguished from inflicted trauma by other characteristic alterations of the bones, by gene tests, and by the absence of corroborative evidence of abuse. The principal disorders known to cause increased susceptibility to fracture without other obvious evidence of bone abnormality are the various moderate-severity forms of osteogenesis imperfecta. Although bone disease of prematurity, rickets due to vitamin D deficiency, Scurvy (vitamin C deficiency), copper deficiency and Menkes disease can increase fracture susceptibility, the bone disease is accompanied by additional evidence allowing it to be easily distinguished from abuse in nearly all cases. In addition to Barlow's Disease or scurvy, a number of medical conditions, including malformations, premature infants, can mimic SBS, even before birth.
Examination by an experienced ophthalmologist is often critical in diagnosing shaken baby syndrome, as particular forms of ocular bleeding are quite characteristic of this condition.
Some medical experts assert that "no case studies have ever been undertaken to probe even a partial list of possible confounding variables/phenomena, such as the presence of intracranial cysts or fluid collections, hydrocephalus, congenital and inherited diseases, infection, coagulation disorders and venous thrombosis, recent immunizations," medications, birth-related brain injuries, "or recent or remote head trauma. Until and unless these and probably many more factors are evaluated, it is inappropriate to select one mechanism only and ignore the rest of the potential causes."
In 2005, a review of several ophthalmology studies and their findings concerning "inflicted childhood neurotrauma" (SBS) was published in the UK, in the quarterly ophthalmology publication Focus. One of the studies "found a correlation between intra-ocular bleeding, anterior optic nerve haemorrhage and subdural haematomas. Post mortem findings of vitreous traction at the apex of retinal folds and the edge of dome shaped haemorrhages and retinoschisis gives some supporting evidence that vitreous forces may cause this shearing damage. There is no adequate model to test this experimentally, so this remains hypothesis, not established fact."
The main scientific finding of two additional studies from the Focus article "was that in cases of retinal haemorrhages with thin film subdurals and in the absence of other injuries that the pathological finding is more commonly that of hypoxic ischaemic encephalopathy rather than diffuse axonal injury. Regardless of the recent debate the observational evidence to date remains that children with non accidental injury may have no visible retinal haemorrhages, whilst non accidental injury and birth are the only circumstances in which multiple retinal haemorrhages in differing layers of the retina have been accurately documented."
The following references documented cases of retinal hemorrhages from accidental head trauma a videotaped minor fall, osteogenesis imperfecta indicating that shaking is not the only possible cause of injury. According to one author, "the presence of retinal hemorrhages is neither necessary nor sufficient for the diagnosis of child abuse." A postvaccinial ocular syndrome was reported as early as 1948, recent papers have been published concerning the occlusion of central retinal vein after hepatitis B vaccination, "The compounding effects of anoxia or hypoxia, anemia, thrombocytopenia, mild coagulopathy, obstruction of retinal venous flow, or possible age-related anatomic variations in the retinal vasculature are not well understood."
Anatomy and pathophysiology
People under the age of three years are especially susceptible to brain damage from shaking. This is due to several anatomical factors. Their heads are bigger and weigh more with respect to their bodies than adults' heads, and their neck muscles are weak and cannot prevent violent motions. Infants' brains are not myelinated; myelin sheaths form in childhood and are complete in adolescence. The brain water content is reduced as neurons gain myelin during development, so babies have a greater percentage of brain water than adults do. Because of this higher water content, children's brains are softer and are much more susceptible to acceleration-deceleration injuries and diffuse axonal injury.
Rotation injury is especially damaging and likely to occur in shaking trauma. The type of injuries caused by shaking injury are usually not caused by falls and impacts from normal play, which are mostly linear forces.
Rotation injury is also referred to as diffuse axonal injury (DAI). A report in 2001, reviewed the brains of 37 infants aged 9 months or less, all of whom died from inflicted head injuries, and 14 control infants who died of other causes. Axonal damage was identified using immunohistochemistry for β-amyloid precursor protein. The observation that the predominant histological abnormality in cases of inflicted head injury in the very young is diffuse hypoxic brain damage, not DAI, can be explained in one of two ways: either the unmyelinated axon of the immature cerebral hemispheres is relatively resistant to traumatic damage, or in shaking-type injuries the brain is not exposed to the forces necessary to produce DAI. Apparently a critical point was missed or overlooked in a paper published in 1968 concerning the results of bioengineering study in conjunction with the U.S. Department of Transportation. This experiment showed, qualitatively, that rotation alone could indeed produce intracranial injury, though it was not shown quantitatively that human beings could generate the required rotational acceleration by manual shaking. This critical omission was not addressed until 19 years later, when it was shown quantitatively that impact was required to generate adequate force. Guthkelch, Caffey, and others either were not aware of, or disregarded, this critical missing piece of information. In the intervening years, and even up to the present, numerous references are made to infants sustaining inflicted brain injury by manual shaking. Yet no laboratory proof of this possibility has ever been put forth. In fact, the available experimental evidence began as far back as 1943, addressed directly in 1987 and reproduced in 2003, seems to indicate the contrary.
"The assessment of the mechanical causation of injury requires training and experience in Injury Biomechanics, a distinct discipline not taught in medical school. Lack of education and experience in Injury Biomechanics, amongst other factors, has led in practice to the proliferation and propagation of inaccurate and sometimes erroneous information on SBS injury mechanisms in the literature." A recent biomechanical experiment in 2005, demonstrated that "forceful shaking can severely injure or kill an infant, this is because the cervical spine would be severely injured and not because subdural hematomas would be caused by high head rotational accelerations. Furthermore, shaking cervical spine injury can occur at much lower levels of head velocity and acceleration than those reported for the SBS. These findings are consistent with the physical laws of injury biomechanics as well as our collective understanding of the fragile infant cervical spine from (1) clinical obstetric experience, (2) automotive medicine and crash safety experience, and (3) common parental experience. We have determined that an infant head subjected to the levels of rotational velocity and acceleration called for in the SBS literature, would experience forces on the infant neck far exceeding the limits for structural failure of the cervical spine. Furthermore, shaking cervical spine injury can occur at much lower levels of head velocity and acceleration than those reported for the SBS.
In 2004, a Scottish database collected data for five years on cases of suspected non-accidental head injury diagnosed after a multiagency assessment and included cases with uncoerced confessions of perpetrators and criminal convictions. Several patterns appeared allowing the categorization of the cases into four predominant types: Hyperacute encephalopathy (6% of all cases); Acute encephalopathy (53% of cases (SBS)); Subacute non-encephalopathic presentation (19% of cases); Chronic extracerebral presentation (22% of cases). Infants can be traumatically injured in many ways, and many instances are unwitnessed. Thus the generic term non-accidental head injury or inflicted traumatic brain injury is occasionally used in preference to shaken baby syndrome, which implies a specific mechanism of injury. An earlier detailed neuropathological study was publish in the UK in 2001, which included immunocytochemistry for microscopic damage.
SBS kills about one third of its victims and permanently and severely disables another third. Problems resulting from SBS include learning disabilities, seizure disorders, speech disability, hydrocephalus, behavioral problems, cerebral palsy, and visual disorders.
Prevention is similar to the prevention of child abuse in general. New parents, babysitters, and other caregivers should be warned about the dangers of shaking infants. Crying is a common trigger for creating irritation and frustration in the caregiver. Some experts have advised that caregivers need strategies to cope with their own frustrations; for example, they should be reminded that they are not always responsible when babies cry.
SBS as a medicolegal concept
The legal import of shaken baby syndrome varies according to circumstances, often involving child welfare and criminal investigations. Such investigations determine whether children are judged safe to remain in their parents / caregivers' care, and whether an individual may be charged with assault, child endangerment, or homicide.
Since the inception of "whiplash shaking" evolving into SBS, the concept has been the subject of criticism by some scientists and jurists for years.
In April 2006, a Daubert hearing (a mini-trial within a trial, conducted before the judge only, not the jury, over the validity and admissibility of expert opinion testimony) was conducted concerning the admissibility of proposed medical and scientific evidence in a Kentucky Circuit Court case. A Grand Jury had indicted the defendant of first-degree criminal abuse by violently shaking a child. The Defendant alleges that the child's medical records indicate that the only significant injury for the victim was a subdural hematoma and retinal hemorrhaging and there was no significant bruising, fractures, or evidence of impact. The Commonwealth's case was based upon the theory of shaken baby syndrome.
The Court after hearing expert testimony and reviewing the evidence, issued the following conclusion and opinion: "The Court can further conclude that based on the medical signs and symptoms, the clinical medical and scientific research communities are in disagreement as to whether it is possible to determine if a given head injury is due to an accident or abuse. Therefore, the Court finds that because the Daubert test has not been met, neither party can call a witness to give an expert opinion as to whether a child's head injury is due to a shaken baby syndrome when only the child exhibits a subdural hematoma and bilateral ocular bleeding. Either party can call a witness to give an expert opinion as to the cause of the injury being due to shaken baby syndrome, if and only, the child exhibits a subdural hematoma and bilateral ocular bleeding, and any other indicia of abuse present such as long-bone injuries, a fractured skull, bruising, or other indications that abuse has occurred."
The trial court's ruling is not considered binding legal precedent. The Commonwealth of Kentucky has appealed the ruling to the state's intermediate appellate court..
In the Summer of 2006 a review of the Shaken Baby Syndrome and the Shaken Impact Syndrome was published in the Military Law Review. This legal review contains an extensive examination of the divergent views of the scientific literature, in addition to examining the divergent views of the legal parameters involving a trial. 
In July of 2005, the Court of Appeals in the United Kingdom reversed or reduced three convictions of SBS, finding that the classic triad of retinal hemorrhage, subdural hematoma, and acute encephalopathy are not 100% diagnostic of SBS and that clinical history is also important. In their ruling, they upheld the clinical concept of SBS but dismissed two cases and reduced the sentence on a third based on their individual merits. In their words: "Whilst a strong pointer to NAHI [non-accidental head injury] on its own we do not think it possible to find that it must automatically and necessarily lead to a diagnosis of NAHI. All the circumstances, including the clinical picture, must be taken into account." The term "non-accidental trauma'" was suggested instead of "SBS" in the March 27, 2004 edition of the British Medical Journal
An additional, alternative explanation for some incidents contemplated as shaken baby syndrome has been proposed. This explanation suggests that a vitamin C deficiency may sometimes play a role in the pathogenesis of shaken baby syndrome, citing that the current SBS pathology determination may be seriously flawed or incomplete This contested hypothesis is based upon a speculated marginal, near scorbutic condition or lack of essential nutrient(s) repletion and a potential elevated histamine level.
The proponents of such hypotheses often question the adequacy of nutrient tissue levels, especially vitamin C, for those children currently or recently ill, bacterial infections, those with higher individual requirements, those suffering from environmental challenges (e.g. allergies), and perhaps transient vaccination related stresses. However, no cases of scurvy mimicking SBS or crib death have been reported, and scurvy typically occurs later in infancy, rarely causes death or intracranial bleeding, and is accompanied by other changes of the bones and skin and invariably an unusually deficient dietary history.
A number of medical personnel recommend that all SBS pathology determinations should include vitamin C repletion history and histamine/vitamin C levels. Additional medical recommendations for the use of vitamins and nutrients as a preventive measure, particularly vitamin C, should be used especially for children with known, projected or suspected stresses/conditions (vaccines) that may deplete certain nutrients.
Although a Barlow’s disease variant (infantile scurvy) may be the most common disease, other diagnoses such as fragile bone disease, hemorrhagic disease of the newborn (vitamin K deficiency) and glutaric aciduria type 1 must also be considered. Gestational problems affecting both mother and fetus, the birthing process, prematurity and nutritional deficits can accelerate skeletal and hemorrhagic pathologies that can also mimic SBS, even before birth. These views are not widely known, utilized or explored in conventional medicine. Nevertheless, favorable court rulings and evidentiary commentary on flawed SBS determinations have been demonstrated by biomechanical studies over the years.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Shaken_baby_syndrome". A list of authors is available in Wikipedia.|