Infant critical head injury could be a remote cause of middle-aged cerebral amyloid angiopathy

Background Cerebral amyloid angiopathy (CAA) is a sporadic condition in the elderly and is associated with Alzheimer’s disease. The younger cases, however, may have a history of traumatic brain injury (TBI) during infancy. Case Presentation We present a case of a 37-year-old man who had cerebral lobar hemorrhage. Magnetic resonance imaging revealed several lobar microbleeds, which along with the asymptomatic, lobar hemorrhages increased every year. At the age of 40 years, he developed mild cognitive impairment. Cerebrospinal fluid (CSF) analysis revealed a markedly decreased level of amyloid β42. Moreover, he had a subdural hematoma during infancy. Thus, we diagnosed him with CAA, which was related to the TBI at infancy. Conclusion TBI at infancy can be a remote cause of middle-aged CAA and dementia. This was supported by the low Aβ42 level in the CSF analysis.