Infantile subdural hematomas due to traffic accidents

The most common cause of subdural hematomas (SDH) in infants is shaken-baby syndrome (SBS). The pathogenesis and natural history of infantile SDH (ISDH) are poorly documented, because in SBS, the date of shaking is usually imprecise and the assault is often repeated. Victims of traffic accidents (TA) form a study group close to experimental conditions, because the trauma is unique, witnessed and dated. We reviewed 18 cases of SDH due to TA in infants under the age of 24 months. Our goal was to investigate the clinical and radiological data and natural history of SDH. A subdural collection was found on the day of trauma in 7 cases. In 3 of these, the collection was already hypodense. The perifalcine region was the most frequent site of intracranial bleeding. Blood hyperdensity was always found on CT scans performed during the first week, and turned hypodense on about the 9th day. Three patients had retinal hemorrhage, of a type distinct from that found in SBS. Drainage of the SDH was required in 14 cases after a mean delay of 13.5 +/- 5.8 days after trauma. Four patients also required a ventriculoperitoneal shunt because of associated hydrocephalus. Our data suggest that impaired CSF drainage plays a large role in the pathogenesis of ISDH. The fact that a single and recent trauma can result in mixed-density ISDH can be of great importance in forensic medicine.