Monday, 6 September 2010

SBS: When Should Retinal Hemorrhages be Considered Suspicious for Non-Accidental Head Injury?

August 30th, 2010
Patient Presentation
A 6-month-old male came to the emergency room with a history of falling out of his mother’s arms onto a bed. The infant cried and mother placed him into the crib as it was time for his nap. About 1 hour later, the infant was crying, had vomitted and the mother felt he was lethargic. The radiologic evaluation showed frontal and interhemispheric acute subdural hematomas and the infant was transferred to a regional children’s hospital for neurosurgical care. The past medical history revealed a full-term, normal spontaneous vaginal delivery without complications. The patient had received routine care and immunizatons. The family history was negative for neurological or congenital abnormalities. There were no reported early or unexplained deaths or miscarriages in the families.
The pertinent physical exam showed normal vital signs. Weight was 10%, head circumference was 95% and length was 25%. The infant had an irritated cry. The anterior fontanelle was bulging. There was bruising from intravenous catheter placement attempts but no other bruising. The rest of the examination was normal. The work-up was negative including screening trauma labs, urine drug screen and hair studies, bleeding studies, urine organic acids, and skeletal survey. The ophthalmological consultant found superficial and deep bilateral retinal hemorrhages that were too numerous to count and covered most of the retinas. During the patient’s clinical course he was placed on anti-epileptic medication and did not have any seizures. Along with the child protection services team, the inpatient hospital physicians reported the child to the Department of Family Services as highly suspicious for a diagnosis of non-accidental trauma. The investigators agreed and the child was discharged to kinship foster care after two weeks of monitoring in the hospital for stabilization of the subdural hemorrhages. The child was to follow-up with neurosurgery in 2 weeks.

Axial image from an unenhanced computed tomography scan of the brain demonstrates high density right frontal and interhemispheric acute subdural hematomas. There is some associated mild swelling of the right cerebral hemisphere.

Shaken baby syndrome (SBS) is a form of non-accidental head injury (NAHI) that occurs when someone violently shakes a child. It may result in brain, eye and/or skeletal injury. The long-term survival is poor with cognitive/behavioral problems, cognitive impairment, cerebral palsy, and/or epilepsy as common problems. In one report 19% of the children died as a direct result of SBS and only 22% had no sequelae at discharge. SBS can be misdiagnosed particularly if it is less severe, has no external bruising (21% of cases) and no history of previous abuse (40%).
SBS often occurs in infancy but can occur in children up to 8 years of age in the literature. Incomplete ophthalmological examination may under-estimate the presence and/or extent of retinal hemorrhages (RH). Complete examination of the entire retina is needed for proper evaluation, which usually means by an ophthalmologist.
Learning Point
Togioka states “[a]lthough the presence of RH [retinal hemorrhage] does not confirm the diagnosis of SBS. RHs are common in abused children and exceedingly rare in cases of accidental head injury.”
Injury typeRH presence is much more common in NAHI (53-80%) than in AHI (accidental head injury, 0-10%). The AHI that has RH associated with it is usually of significant force (e.g. motor vehicle accident). Short falls (< 4 feet) are extremely unlikely to cause RHs. In one study of 287 children, no children who had an accidental fall < 4 feet had RH, while 25% of those with a fall in the abused group had RHs.
Flame shaped RHs are the most common form of RH seen in SBS. RHs appear to generally start more centrally and superficially within the retina and then spread more peripherally and deeper with an increasing amount of force/trauma. Studies have shown peripheral RHs are seen in 27% of NAHI and 0% in AHI. Unilateral retinal hemorrhages can be seen in NAHI (14-21%). Bilateral RH are found in 58-100% with NAHI and in only 1.5% of accidental head injury. Other ophthalmological pathology has been linked to NAHI including hemorrhages in other parts of the eye, retinal folds, macular folds and Roth spots.
Other diseases that can cause RH include:
Glutaric aciduria type 1
Hemorrhage disease of the newborn
Hermansky-Pudlak Syndrome
Osteogenesis imperfecta
Protein C deficiency (homozygous) and other coagulopathies
Terson syndrome
Data shows that forceful emesis, forceful coughing, seizures and prolonged chest compressions basically do not cause the RHs seen in SBS. RH can be seen after birth in up to 30-40% of deliveries but most are resolved in 3-9 days after birth.While alternative explanations for NAHI can be hypothesized, Moran noted that “[t]here is no disease or condition that fully mimics the complete diagnostic picture of SBS.”


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