Characteristics distinguishing abusive head trauma from accidental head trauma in infants with traumatic intracranial hemorrhage in Japan

Aim: To identify markers for detecting abusive head trauma (AHT) and its characteristics in the Japanese population. Methods: We retrospectively reviewed the clinical records of 166 infants with traumatic intracranial hemorrhage between 2002 and 2013 in three tertiary institutions in Japan. The infants were classified into AHT (57), suspected AHT (24), and accidental (85) group based on the defined criteria. We compared clinical presentations and computed tomography findings among these three groups and also compared age distribution of infants with AHT in our study to those in the USA. Results: Age distribution of AHT cases is significantly higher in our study than in the USA (P < 0.001). The rates of male sex, bruising, retinal hemorrhage, subdural hematoma, cerebral edema, and neurological sequelae were significantly higher, and those of skull fracture and scalp finding were significantly lower, in the AHT group than in the accidental group (P < 0.05). In the multivariable analysis of the infants with subdural hematoma, absence of skull fracture (odds ratio = 42.1; 95% confidence interval, 3.5-507.7, P = 0.003) was associated with AHT. Conclusions: The age range of AHT in Japan is significantly different from that of countries in Europe and North America because of familial and sociocultural situations. Absence of bruising, and rib or long bone fractures did not reduce the likelihood of AHT. Subdural hematoma without findings of an impact to the head strongly suggested AHT. Abusive head trauma is a global problem, however, diagnosis and defensive measures likely need to be tailored to accommodate cultural risk factors.