Amyloid-β related angiitis presenting as eosinophilic meningitis: a case report

Background: Eosinophilic meningitis is uncommon and often attributed to infectious causes. Case presentation: We describe a case of a 72-year-old man who presented with subacute onset eosinophilic meningitis, vasculitis, and intracranial hypertension with progressive and severe neurologic symptoms. Brain MRI demonstrated multifocal strokes and co-localized right temporo-parieto-occipital vasogenic edema, cortical superficial siderosis, and diffuse leptomeningeal enhancement. He ultimately underwent brain biopsy with immunohistochemical stains for amyloid-β and Congo red that were extensively positive in the blood vessel walls and in numerous diffuse and neuritic parenchymal confirming a diagnosis of amyloid-β related angiitis. He was treated with immunosuppression with clinical stabilization. Conclusions: Amyloid-β related angiitis is an underrecognized cause of eosinophilic meningitis that can present fulminantly and is typically responsive to immunosuppression. The presence of eosinophils may provide additional clues to the underlying pathophysiology of amyloid-β related angiitis.