Introduction. Amyloid-beta-related angiitis (ABRA) is a form of CNS vasculitis 
in which perivascular beta-amyloid in the intracerebral vessels is thought to 
act as a trigger for inflammation mediated by CD68+ macrophages and CD3+ T 
lymphocytes. Patients with severe ABRA may develop coma responsive to 
immunosuppressive treatment. Case Presentation. A 57-year-old man presented to 
the neurological intensive care unit febrile, obtunded, and with a left 
hemiparesis. He had suffered from intermittent left arm weakness and numbness 
for several months prior. Serum and cerebrospinal fluid studies showed a 
lymphocytic leukocytosis in the cerebrospinal fluid (CSF), but no other evidence 
of infection, and the patient underwent a brain biopsy. Histopathological 
examination demonstrated amyloid angiopathy, with an extensive perivascular 
lymphocytic infiltrate, indicative of ABRA. The patient was started on 
cyclophosphamide and steroids. Following a week of treatment he awakened and 
over several weeks made a significant neurological recovery. Conclusions. ABRA 
can have a variety of clinical presentations, including impairments in 
consciousness and coma. Accurate pathological diagnosis, followed by aggressive 
immunosuppression, can lead to impressive neurological improvements. This 
diagnosis should be considered in patients with paroxysmal recurrent 
neurological symptoms and an accelerated progression.