Fulminant Amyloid β-Related Angiitis With Herniation and Rapid Response to Tocilizumab: A Case Report.

Abstract

Objectives: Amyloid β-related angiitis (ABRA) is a rare, inflammatory vasculopathy resulting from intravascular amyloid deposition. We describe a refractory presentation of ABRA and its response to tocilizumab.

Methods: Single-patient, biopsy-confirmed ABRA with serial MRI and clinical outcomes. Treatments included high-dose IV methylprednisolone, hyperosmolar therapy, cyclophosphamide, and escalation to tocilizumab.

Results: A 70-year-old woman presented with seizure and focal deficits. Initial MRI showed multifocal subcortical T2/FLAIR hyperintensities with cortical microhemorrhages without enhancement. Despite steroids, interval imaging showed progressive vasogenic edema, new leptomeningeal enhancement, and rising microhemorrhage burden. She developed severe headache and worsening hemiparesis; CT/MRI demonstrated marked edema with subfalcine/uncal herniation. Biopsy confirmed ABRA. Edema did not improve with steroids, maximal hyperosmolar therapy, or cyclophosphamide. After tocilizumab, MRI within 48 hours showed reduced edema and midline shift with near-resolution of sulcal enhancement; hemiparesis markedly improved without hemicraniectomy.

Discussion: We expand the phenotypic spectrum of ABRA by presenting a herniation syndrome associated with fulminant disease and a clear clinicoradiographic natural history. The precipitous progression of microhemorrhage accrual suggests a pathophysiologically distinct mechanism of disease from cerebral amyloid angiopathy-related inflammation. IL-6 receptor blockade was associated with rapid clinical and radiographic improvement and stabilization, supporting prospective evaluation of tocilizumab in amyloid-related neuroinflammatory disorders.