Cerebral amyloid angiopathy as a cause of subarachnoid hemorrhage

Cerebral amyloid angiopathy is a pathologic condition characterized by the deposition of amyloid in the walls of small vessels in the cerebral cortex and meninges. Intracerebral hemorrhage is common in persons with this condition, but pure subarachnoid or subdural hemorrhage is rarely seen. Recently, the existence of two types of amyloid proteins related to cerebral amyloid angiopathy, ß protein and cystatin C, has been reported, and Immunohis-tochemical methods using antisera to these proteins have become available. We describe a patient with fatal subarachnoid hemorrhage presumably caused by ß protein-type cerebral amyloid angiopathy, which was demonstrated immunohistochemicaliy by using a monoclonal antibody to a synthetic peptide corresponding to residues 8-17 of ß protein. We suggest that ft protein-type cerebral amyloid angiopathy is a possible etiologic factor in subarachnoid hemorrhage of unknown cause.