Background: After infant deaths due to non-accidental head injury (NAHI) with subdural hematoma (SDH), the magistrates ask experts to date the traumatic event. To do so, the expert only has tools based on adult series of NAHI. We aimed to develop an SDH dating system applicable to infants aged under 3 years.
Methods and results: We studied a retrospective multicenter collection of 235 infants who died between the ages of 0 and 36 months, diagnosed with SDH by forensic pathological examination and with known posttraumatic interval (PTI). Two pathologists assessed blindly and independently 12 histomorphological criteria relating to the clot and 14 relating to the dura mater in 73 victims (31 girls, 42 boys) whose median age was 3.8 months. Histopathological changes were significantly correlated with PTI for the appearance of red blood cells (RBCs) and the presence or absence of siderophages, and regarding the dura mater, the quantity of lymphocytes, macrophages, and siderophages; presence or absence of hematoidin deposits; collagen and fibroblast formation; neomembrane thickness; and presence or absence of neovascularization. Dating systems for SDH in adults are not applicable to infants. Notably, neomembrane of organized connective tissue is formed earlier in infants than in adults.
Conclusion: Our dating system improves the precision and reliability of forensic pathological expert examination of NAHI, particularly for age estimation of SDH in infants. However, the expert can only define a time interval. Histopathology is indispensable to detect repetitive trauma.
Keywords: Age estimation; Dating; Histology; Posttraumatic interval; Shaken baby syndrome; Subdural hematoma.