Infantile subdural hematoma in Japan: A multicenter, retrospective study by the J-HITs (Japanese head injury of infants and toddlers study) group

OBJECTIVE: Subdural hematoma in infants or toddlers has often been linked to abuse, but it is not clear how many cases actually occur and how many are suspected of abuse. The purpose of this study was to investigate subdural hematoma in infants and toddlers in Japan. METHODS: This multicenter, retrospective study reviewed the clinical records of children younger than 4 years with head trauma who were diagnosed with any finding on head computed tomography (CT) and/or magnetic resonance imaging (MRI), such as skull fracture and/or intracranial injury. A total of 452 children were included. The group suspected to have been abused was classified as nonaccidental, and the group considered to have been caused by an accident was classified as accidental. Subdural hematoma and other factors were examined on multivariate analysis to identify which factors increase the risk of nonaccidental injuries. RESULTS: Of the 452 patients, 158 were diagnosed with subdural hematoma. Subdural hematoma was the most common finding intracranial finding in head trauma in infants and toddlers. A total of 51 patients were classified into the nonaccidental group, and 107 patients were classified into the accidental group. The age of patients with subdural hematoma showed a bimodal pattern. The mean age of the accidental group with subdural hematoma was significantly older than that in the nonaccidental group (10.2 months vs 5.9 months, respectively. p < 0.001). Multivariate analysis showed that patients under 5 months old, retinal hemorrhage, and seizure were significant risk factors for nonaccidental injury (odds ratio (OR) 3.86, p = 0.0011; OR 7.63, p < 0.001; OR 2.49, p = 0.03; respectively). On the other hand, the odds ratio for subdural hematoma was 1.96, and no significant difference was observed (p = 0.34). CONCLUSIONS: At least in Japanese children, infantile subdural hematoma was frequently observed not only in nonaccidental but also in accidental injuries. In infants with head trauma, age, the presence of retinal hemorrhage, and the presence of seizures should be considered when determining whether they were abused. Subdural hematoma is also a powerful finding to detect abuse, but care should be taken because, in some ethnic groups, such as the Japanese, there are many accidental cases.