CEREBRAL AMYLOID ANGIOPATHY-RELATED INFLAMMATION PRESENTING WITH A STROKE-LIKE EPISODE.

Cerebral amyloid angiopathy (CAA) is characterised by β-amyloid deposition in the walls of small to medium sized arteries of the cerebral cortex and the leptomeninges. In a significant proportion of patients, CAA is the probable cause of non-traumatic primary cerebral haemorrhage, particularly in those who are over 55 years of age and have controlled blood pressure. Cerebral amyloid angiopathy-related inflammation (CAA-ri) is an uncommon and aggressive subtype of CAA, which is thought to be caused by an immune reaction to the deposits of β-amyloid. It has a variety of presentations that can mimic other focal and diffuse neurological disorders. Radiographically, its classic presentation is asymmetric cortical or subcortical white matter hyperintense foci due to multiple microhaemorrhages on T2-weighted or fluid attenuated inversion recovery (FLAIR) images. Although definite diagnosis requires brain and leptomeningeal biopsy, diagnostic criteria for probable CAA-ri based on a combination of clinical and radiological features were validated in 2015. We describe a patient with probable CAA-ri mimicking stroke and review the clinical and radiological features important for a proper differential diagnosis between ischaemic stroke (IS) and CAA-ri, and its subsequent appropriate treatment. LEARNING POINTS: MRI is a crucial tool for the diagnostic evaluation of cerebral amyloid angiopathy-related inflammation (CAA-ri).A high index of suspicion and awareness of CAA-ri is necessary for correct diagnosis in stroke-like presentations of the condition.The treatment of choice for CAA-ri is empirical corticosteroid therapy, which is associated with clinical and radiological improvement.