Primary Angiitis of the Central Nervous System (PACNS): a 12-year single-center review (P1.166)

Objective: To characterize the clinical and radiological features of PACNS in our local population. Background: PACNS is a rare condition that presents a challenging diagnosis to clinicians. It has protean manifestations for which there is no well-defined diagnostic or treatment guide. Design/Methods: We retrospectively reviewed all patients who had histologically-confirmed or clinically-diagnosed PACNS at our tertiary center from 2005 to 2016. All patients underwent laboratory investigations, MRIs and brain biopsies that excluded other conditions, including reversible cerebral vasoconstriction syndrome (n=5) and secondary cerebral vasculitis (n=27). We collected clinical data, and reviewed MRIs and when available, cerebral angiograms, at (i) initial presentation and (ii) an interval before brain biopsy. Results: Seven patients (4 women; 3 men) were analyzed; median age was 59 (range 46–82) years. Five patients had brain biopsies demonstrating vasculitis; 2 had non-specific findings. Median duration from initial presentation to diagnosis was 3.9 (range 1.9–349.4) weeks. Commonest presenting symptoms were focal weakness (n=3), altered cognition (n=3) and headache (n=2). Six patients had raised blood-WBC (range 9.9–22 x10 9 /L) and 3 had abnormal CSF findings (CSF-WBC 22–75cells/u; CSF-protein 0.7–2.3g/L); only 1 had abnormal antinuclear antibody. All patients had abnormal initial MRIs demonstrating acute infarct (n=2), intraparenchymal bleed (n=1), subarachnoid bleed (n=1), microbleed (n=1), uni/multifocal T2-signal abnormalities (n=3) and periventricular/deep white-matter hyperintensities (n=5); however only 2 of 5 patients with angiograms showed arterial stenoses (1 MRA; 1 4-vessel angiogram [4-VA]). Interval MRIs demonstrated leptomeningeal enhancement (n=1), new areas of acute infarct (n=1), microbleed (n=3) and focal T2-signal abnormalities (n=4). Among the 3 patients with initial negative MRA, 1 had a subsequent positive 4-VA. In all, 2 of 5 patients who underwent cerebral angiograms had normal results (1 MRA only; 1 MRA+4-VA). Conclusions: PACNS has diverse clinical and radiological manifestations. Cerebral angiograms can be normal, thus a high index of suspicion is required for early diagnosis and treatment. Disclosure: Dr. Guan Zhong has nothing to disclose. Dr. Yu has nothing to disclose. Dr. Chng has nothing to disclose. Dr. Lee has nothing to disclose. Dr. Tham has nothing to disclose. Dr. Lin has nothing to disclose.