1. What is shaken baby syndrome?
Shaken baby syndrome is a term used to describe the constellation of signs and symptoms resulting from violent shaking or shaking and impacting of the head of an infant or small child. The degree of brain damage depends on the amount and duration of the shaking and the forces involved in impact of the head. Signs and symptoms range on a spectrum of neurological alterations from minor (irritability, lethargy, tremors, vomiting) to major (seizures, coma, stupor, death). These neurological changes are due to destruction of brain cells secondary to trauma, lack of oxygen to the brain cells, and swelling of the brain. Extensive retinal hemorrhages in one or both eyes are found in the vast majority of these cases. The classic triad of subdural hematoma, brain swelling and retinal hemorrhages are accompanied in some, but not all, cases by bruising of the part of the body used as a "handle" for shaking. Fractures of the long bones and/or of the ribs may also be seen in some cases. In many cases, however, there is no external evidence of trauma either to the head or the body. (Definition provided by Robert Reece, M.D. Dr. Reece is a clinical professor of Pediatrics at the Tufts University School of Medicine.)
Approximately 20% of cases are fatal in the first few days after injury and the majority of the survivors are left with handicaps ranging from mild - learning disorders, behavioral changes - to moderate and severe, such as profound mental and developmental retardation, paralysis, blindness, inability to eat or exist in a permanent vegetative state.
In a response provided by Dr. John Lancon, he defined shaken baby syndrome as the constellation of non-accidental intracranial and ocular hemorrhages occurring in infants and young children. Other injuries, including cutaneous bruises, lacerations, burns, parenchymal brain injuries, rib fractures, extremity fractures, and injuries to various internal organs may be seen in the setting of shaken baby syndrome, but are not required for diagnosis. Some experts have suggested changing the name of the syndrome to shaken impact syndrome to emphasize the importance of cranial impact in the genesis of the severe brain injury seen in some victims of shaken baby syndrome.
2. What are subdural hemorrhages, subarachnoid and epidural hemorrhages and the differences between them?
Epidural, subdural, and subarachnoid hemorrhages are best understood by reviewing the anatomy of the meninges (membrane coverings of the brain):
The meninges are divided into three layers: the dura mater, arachnoid, and pia mater. The outer layer, the dura mater, lines the inner surfaces of the skull and forms several reflections that partially separate the cerebral hemispheres along the midline (interhemispheric fissure) and the cerebrum from the cerebellum. The dura mater is rather firmly adherent to the skull, particularly at the junctions (cranial sutures) of the various bones which comprise the skull. The potential space between the skull and the dura mater is referred to as the epidural space. A hemorrhage into this space is referred to as an epidural hemorrhage. These hemorrhages are usually the result of a tear in a meningeal artery.
The middle layer of the meninges is the arachnoid. It is a thin membrane likened in appearance to a spider's web. Under normal conditions, the arachnoid is attached to the overlying dura. The potential space between the dura mater and the arachnoid is the subdural space. A hemorrhage into this space is referred to as a subdural hemorrhage. These hemorrhages are usually the result of a tear in one of the small veins which traverses the space between the brain and the dura mater (bridging veins).
Finally, the pia mater is the innermost layer. It is delicate and intimately adherent to the surface of the brain. The space between the arachnoid and the pia mater is the subarachnoid space. A hemorrhage into this space is referred to as a subarachnoid hemorrhage.
Epidural, subdural, and subarachnoid hemorrhages are sometimes referred to as extra-axial hemorrhages, indicating that they occur outside the substance of the brain. Although all three types of hemorrhage may occur with non-accidental trauma, the classic intracranial hemorrhage seen in Shaken Baby Syndrome is the subdural hemorrhage. In this setting, the subdural hemorrhage is often bilateral or located in the posterior interhemispheric fissure. (Answer provided by John Lancon, M.D., Assistant Professor of Neurosurgery at the University of Mississippi Medical Center, Jackson, MS.)
3. How much force is necessary to cause injuries in shaken baby syndrome? How many times do you have to shake an infant or young child to cause damage?
No firm answer exists as to the exact number of shakes necessary to create the clinical picture nor for how long a person might typically shake a child in abusive circumstances.... Shaking probably lasts a maximum of 20 seconds or less. In most cases the period of shaking is 5 to 10 seconds. To cause brain damage sufficient to allow clinical detection of the syndrome, severe forces must be used. On mechanical/physiologic grounds and by experience with perpetrators who have been convicted or confessed to the shaking, it is clear that to lift an infant and shake requires an adult or an adult-sized person.
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:52.
4. What is the retina of the eye?
As defined by Webster, the retina is the inner coat of the back of the eye, containing cells sensitive to light. Images formed on the retina by the lens of the eye are carried by the optic nerve to the brain.
5. What are retinal hemorrhages and what is their relationship to shaken baby syndrome?
From Levin AV: Ocular Manifestations of Child Abuse in Reece RM and Child Abuse Medical Diagnosis and Management by Robert Reece, M.D. Ludwig- Retinal hemorrhages are common in abused children. Retinal hemorrhages are common in shaken infants with reports ranging from 30 to 100% depending on the population studied. Describing the retinal hemorrhages in terms of type, number and distribution is essential if one is to appreciate the specificity of any particular child's eye examination. A few intraretinal hemorrhages confined to the posterior pole may be very nonspecific and could result from numerous other causes. But the presence of massive retinal hemorrhage throughout the entire retina (subretinal, intraretinal, and preretinal) is virtually diagnostic of shaken baby syndrome, as it is very rare to see such a presentation of any other systemic or ocular disease that would not otherwise be easily distinguished by the presence of other supportive signs. Too often, in the medical literature and other settings, comments are made about the specificity or implications of "retinal hemorrhages". The use of this rather generic term is no more helpful in determining a diagnosis of accidental versus nonaccidental injury than is the use of the term "fracture" without describing the involved bone and type of fracture.
The nonophthalmologist is at a distinct disadvantage in achieving an adequate description of intraocular hemorrhage because of lack of routine exposure, failure to dilate the pupil pharmacologically, and the limitations of the direct ophthalmoscope, particularly in the awake and noncooperative infant. False-positive and false-negative examinations may occur; if documented in the medical record they may lead to confusing evidence in a legal proceeding. It is essential that ophthalmology consultation be obtained in all cases in which shaken baby syndrome is suspected, if not all cases of unexplained sudden infant death. Except in those cases where a child's pupils may be fixed and dilated because of imminent death, the pupils should always be pharmacologically dilated so that the entire retina may be viewed. If there are concerns about preserving pupillary activity for neurologic monitoring, options include the use of short-acting agents (phenylephrine, 2.5%; tropicamide, 1% ), which will wear off within 4 to 6 hours, dilating one pupil at a time, or if no other options exist, using small pupil indirect ophthalmoscopy. Ideally, the examination should be conducted within 24 hours of presentation or recognition of the possibility of nonaccidental injury. The ophthalmologist should be encouraged to write a descriptive note and perform retinal photography by using either a standard hand-held fundus camera, video indirect ophthalmoscopy, or the RetCam photographic unit. Such equipment is extremely costly and may not be available at many centers, but detailed drawings and scoring systems can also be useful.
One specific retinal abnormality, traumatic retinoschisis, is essential to recognize as it is highly specific for shaken baby syndrome and has never been described in any other condition of infants and young children in the shaken baby range. At these ages, the vitreous is quite firmly adherent to the macula and retinal blood vessels, much more so than in the adult. As a result, the shaking forces applied indirectly to the vitreous exert shearing tractional forces on the retina, in particular the macula, causing it to split its layers, forming a cystic cavity that may be partially or completely filled with blood. It also is important to avoid the common error in identifying these blood collections as "preretinal" or "subhyaloid" (between the vitreous and the retina). Recognition of traumatic retinoschisis is aided by the identification of hemorrhagic or hypopigmented circumlinear ridges or lines at the edges of the lesion. These demarcations also have been called paramacular folds. Schisis-like cavities also can form directly over blood vessels, although this is a less specific finding that may be mimicked by virtually any disorder in which a major vessel can have a local bleed (e.g., vasculitis, leukemia). The blood within a retinoschisis cavity may leak into the vitreous, making careful monitoring and follow-up essential.
Levin AV. Ocular Manifestations of Child Abuse. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:99-100.
6. Do falls cause injuries similar to shaken baby syndrome?
Several studies have been done in relation to infant and children's injuries sustained in "short" falls.
Click here to view the studies.
These falls are from heights such as those associated with sofas, changing tables, beds or with falls associated with the caretaker falling while carrying the child. The existing studies cited here, taken in totality, support the conclusion that not only are accidental falls from heights of less than several stories unlikely to result in death, but also that severe intracranial injuries ascribed to short falls likely indicate abusive injury. Accidental falls, even down stairways, are not generally the cause of intracranial injuries in infants. Household falls from furniture or down stairs most commonly result in minor trauma, but these falls, particularly when from the arms of a caretaker, may cause skull fractures, some of which may be complex or depressed, epidural hematomas, and at times clinically benign focal subarachnoid hemorrhages or small parenchymal contusions. Falls down stairs in walkers infrequently cause large intraparenchymal contusions with potential neurologic consequences, but only one death has been reported. High-velocity impact injuries, falls from extreme heights, or falls onto extremely hard surfaces provide the opportunities for more severe injury. Rarely do these catastrophic events occur without a corroborated history. If these factors are not present to account for severe head injury, the examining physician must strongly consider abuse.
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:66.
7. Predisposing factors in abusive head trauma
Many factors, some easily quantified and others elusive, place a child at greatest risk for abusive head injury. The child's age, physiologic factors, and the particular type of injury sustained are relatively concrete. Less easily calculated are the factors of caretaker stress and the available capability to manage that stress. The clearest of the predisposing factors is the young age of the injured child. The mean age of children with abusive head injury is 5 to 9 months, with the majority being younger than 9 months. The high susceptibility of the infant brain and cerebral vessels to injury relates to many factors, including the disproportionately large size of the infant's head, relatively weak neck muscles, the pliability of the infant's skull, open sutures (and a large fontanel), the large subarachnoid space, and the high water content of the infantile brain. The vessels involved in subdural and subarachnoid hemorrhages bridging the space between the meninges and the skull are less tightly bound. These factors particularly dispose an infant to serious injury when grabbed by the trunk or shoulders and shaken. Injury in young children is also facilitated by the physical helplessness of the infant and the disparity in size between infants and their caretakers.
Whether shaped by cultural force, impulsive response to anger and aggression, and/or other factors, the stimulus to abusive injury is often attributed to the irritation caused by a crying child. The normal infant spends 2 to 3 hours each day crying, and 20% to 30% of infants exceed that amount of time, sometimes substantially. Infants often cry on an apparently irrational basis, and may not respond to a parent's initial attempts to comfort them. Crying becomes particularly problematic during the 6-week to 4-month age bracket, an age period that coincides with the peak incidence of shaken baby syndrome. Ironically, the abusive shaking behavior may be self-reinforcing, because the infant who is shaken or otherwise brain injured may cease to cry because of the injury inflicted by the shaking. The caretaker may associate such cessation with a gratifying response in that the infant ceases crying and the abuser therefore repeats the behavior. Thus, an initial action, impulsive and triggered by stress, may have immediate positive results for the caretaker who simply wishes the crying to cease. The quiet, drowsy baby displays the desired behavior and may not exhibit severe symptoms after the first shaking, possibly leading the caretaker to conclude that shaking obtains an appropriate response to irritation or upset.
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:55-56.
8. How many children are injured or die from shaken baby syndrome?
This is a frequently asked question and unfortunately there are not good statistics. Until a method for collecting such statistics is established, the true incidence will not be known. It is recognized, however, that it is the most common cause of mortality and accounts for the most long-term disability in infants and young children due to physical child abuse. Based on a North Carolina research project published in the Journal of the American Medical Association in August of 2003, approximately 1,300 U.S. children experience severe or fatal head trauma from child abuse every year. The same study revealed that approximately 30 per 100,000 children under age 1 suffered inflicted brain injuries."
9. What are CT scans and MRI's and how are they used to diagnose shaken baby syndrome?
A CT (computed tomography) scan is an X-ray technique that produces a film representing a detailed cross section of tissue structure. This procedure is painless, non-invasive, and requires no special preparation. CT is a narrow beam of x-rays that rotate in a continuous 360 motion around the patient to image the body is cross-sectional slices. MRI (magnetic resonance imaging) is medical imaging that uses radio-frequency radiation as its source of energy.
The imaging evaluation of an infant with an acute brain injury depends on the urgency and severity of the clinical situation. A severely injured, apneic, and seizing child should, after a clinical assessment, undergo a CT scan of the brain. CT offers sufficient resolution and detail to allow the surgeon to make the necessary decision. The initial CT should be obtained without contrast enhancement and at intervals sufficient to cover the brain in a timely fashion but without large intervals. Larger injuries, subarachnoid hemorrhage, and diffuse hypoxic-ischemic changes are often better demonstrated by CT. For a picture view the University of Hawaii Dept of Pediatrics web-site.
MR imaging should be a confirmatory or supplementary study in patients suffering abusive head injury. MR scans are often obtained several days to a week after the acute presentation to better delineate the types of injury and to document extra-axial fluid collections around the brain. After six to eight weeks, MR imaging is useful in showing the changes in brain parenchyma (tissue). In general, parenchymal injuries such as shearing injuries and diffuse axonal injuries are best seen on MR images.
Most skull fractures are best shown by skull radiographs (x-rays).
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:59.
10. How can the injuries be dated and the time of injuries be determined?
Three major sources of information are used to establish the timing of intracranial injuries: clinical history, physiologic data, and imaging. These sources work in synergy and, if used separately, may lead to apparent disagreements between experts. In most instances, imaging data is less precise than physiologic data; clinical history, if reliable, is the most precise.
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:70.
11. What is the outcome or prognosis of victims of SBS?
From Child Abuse Medical Diagnosis and Management by Robert Reece, M.D.- At best estimate, one third of abusive head injury victims who develop symptoms escape without significant handicapping conditions. Many children are left with blindness, seizure disorders, profound mental retardation, spastic diplegia (paralysis of both sides) or quadriplegia (all sides). Some continue to live in a vegetative state.
Milder cases of abusive head injury tend to have less well-defined outcomes. In those children with less severe injuries, one finds milder mental retardation, seizure disorders or developmental delays. The spectrum of abnormalities ascribed to even milder injuries includes learning disabilities, personality changes or behavior problems.
Cerebral palsy that is of undefined origin (i.e., no history of birth or intrauterine problems) may be attributed to abusive injury, particularly shaking; however, this relationship is difficult to demonstrate consistently.
Alexander RC, Levitt CJ, Smith WL. Abusive Head Trauma. In: Reece RM, Ludwig S, eds. Child Abuse: Medical Diagnosis and Management 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:73.
12. How can SBS be prevented?
It is important to note that SBS is preventable. Shaking occurs frequently when a frustrated care giver loses control with an inconsolable crying baby. It is important to realize just saying "don't shake a baby" is not enough. A plan of action or suggestions to deal with the situation need to be offered. Parents and other care providers need assurance that allowing a baby to cry is okay if all their needs have been met. The care provider should address their stress level and try stress management.
Parents should share the message of the dangers of shaking with all who care for their infant or child, including spouses, their own parents, siblings, day care providers and others. Parents need to let those caring for the infant know that it is okay to call for help when needed.
13. Can tossing or rough play cause SBS?
The National Center on Shaken Baby Syndrome fields numerous calls from anxious parents and care givers each week, wondering if everyday play activities can possibly cause shaken baby syndrome. These parents usually call after a well-meaning relative or friend has cautioned them regarding such activities as using an infant swing, tossing a child in the air or bouncing a baby on the caregiver's knee. These callers are reassured once a staff member from the National Center explains SBS and the violence necessary to cause it.
The National Center and its International Advisory Board issues this position statement on the relationship between shaken baby syndrome and normal affectionate handling or innocent play activities:
Shaken baby syndrome, which may result in severe brain trauma, is caused when a child is violently shaken such that the head is subjected to back and forth motion in one or more directions resulting in rapid repeated severe acceleration and deceleration of the head. The medical literature and ongoing research around the world have characterized shaken baby syndrome as well as other forms of accidental and non-accidental injury. Activities involving an infant or a child such as tossing in the air, bouncing on the knee, placing a child in an infant swing or jogging with them in a back pack, do not cause the brain, bone, and eye injuries characteristic of shaken baby syndrome.
The National Center on Shaken Baby Syndrome recognizes and supports positions offered by The American Academy of Pediatrics (AAP) and the National Association of Medical Examiners (NAME) in reference to the mechanisms that cause shaken baby syndrome. The forces required are distinctly different than those sustained by children in the activities described above or in short falls.
The American Academy of Pediatrics Policy Statement on shaken baby syndrome reads:
"Shaken baby syndrome is a term often used by physicians and the public to describe abusive head trauma inflicted on infants and young children. Although shaking an infant has the potential to cause neurologic injury, blunt impact or a combination of shaking and blunt impact cause injury as well. Spinal cord injury and secondary hypoxic ischemic injury can contribute to poor outcomes of victims."
Abusive Head Trauma in Infants and Children- Policy Statement PEDIATRICS Vol. 123 No. 5 May 2009, pp. 1409-1411
Additionally the National Association of Medical Examiners Ad Hoc Committee on Shaken Baby Syndrome states:
...experts in many scientific fields have investigated whether such apparently innocent practices as tossing a baby into the air and other playful maneuvers might cause brain damage by a similar shaking mechanism. Currently, it is generally accepted that such playful practices do not result in injuries to the young child's brain. The type of shaking that is thought to result in significant brain injury involves holding the child by the thorax or an extremity and violently shaking the child back and forth, causing the head to forcefully whiplash forward and backward with repeated accelerations and decelerations in each direction. (Case et al., 2001)