The importance of amyloid β protein in cerebrospinal fluid when you recognize convexal subarachnoid hemorrhage.

Background: Convexal subarachnoid hemorrhage (cSAH) is sometimes experienced in cerebral amyloid angiopathy (CAA), but ones that are repeated within a brief time period are not common. Also, it is often difficult to diagnose CAA when you experience a case of cSAH. Methods: We examined the clinical course of 2 cases that showed cSAH repeatedly. We examined cerebrospinal fluid (CSF) concentrations of amyloid β protein (Aβ) 40 and 42 and tau protein as additional evidence for a diagnosis of CAA. Results: Case 1 presented with transient motor paresis of the left hand and case 2 with transient sensory disturbance of the left hand. CT scans showed cSAH on the right central sulcus in both patients. Case 1 showed development of intracerebral hemorrhage on the frontal lobe near the right central sulcus. Case 2 showed relapse of cSAH with recurrence of the same symptoms. These cases could not be diagnosed by image analysis, but were considered CAA by Aβ40, Aβ42 and tau protein in CSF. Conclusion: Aβ in CSF can be presented here as support for the diagnosis of CAA that is difficult to diagnose by Boston criteria.