Amyloid beta-related angiitis--a case report and comprehensive review of literature of 94 cases

Background: Amyloid Beta-Related Angiitis (ABRA) is a rare cause of central nervous system vasculitis complicating cerebral amyloid angiopathy. Data regarding its prevalence, clinical features, management, and outcomes are scant.

Objectives: To describe a patient with ABRA and discuss clinical features and management of ABRA.

Methods: A case report and review of literature were conducted of all reported cases of ABRA in the English literature.

Results: The exact etiology of ABRA is not clear, though it is thought to be secondary to an inflammatory response to beta amyloid (Aβ) in the walls of blood vessels. Role of ApoE e4/e4 genotype and its association with autoimmune diseases have been reported. ABRA shares many clinical features with primary CNS vasculitis. Patients with ABRA are relatively younger than those with non-inflammatory cerebral amyloid angiopathy (CAA), but older than patients with primary central nervous system vasculitis (PCNSV). Acute-onset cognitive behavioral abnormalities, focal neurological deficits, seizures, or unusual headaches are the most common presentations of ABRA. Majority have elevated CSF proteins. Up to 70% of patients have ApoE e4/e4 genotype. MRI is the most important diagnostic tool and is almost always abnormal. Characteristically, MRI shows hyperintensities on T2-weighted (T2W) or fluid-attenuation inversion recovery (FLAIR) images with minimal gadolinium enhancement. On susceptibility-weighted images (SWI), a majority of the patients have the presence of microbleeds at cortico-subcortical junction. It may be possible to diagnose typical patients based on clinical features and MRI findings alone, obviating the need for brain biopsy. Brain biopsy is the gold standard and shows transmural granulomatous vasculitis superimposed on CAA. ABRA responds well to steroids in majority. Patients usually need additional immunosuppressants, especially to prevent relapse. MRI abnormalities resolve with treatment and recur with the relapse.

Conclusions: ABRA is a rare but treatable cause of progressive dementia and should be considered in the differential diagnosis of rapid-onset CNS dysfunction in patients older than 60 years. It has characteristic MRI findings and responds well to steroids and other immunosuppressant therapy.