Primary Angiitis of the CNS: A Systematic Review and Meta-analysis

Background and Objectives To facilitate and improve the diagnostic and therapeutic process by systematically reviewing studies on patients with primary angiitis of the CNS (PACNS). Methods We searched PubMed, looking at the period between 1988 and February 2020. Studies with adult patients with PACNS were included. We extracted and pooled proportions using fixed-effects models. Main outcomes were proportions of patients with certain clinical, imaging, and laboratory characteristics and neurologic outcomes. Results We identified 46 cohort studies including a total of 911 patients (41% biopsy confirmed, 43% angiogram confirmed, and 16% without clear assignment to the diagnostic procedure). The most frequent onset symptoms were focal neurologic signs (63%), headache (51%), and cognitive impairment (41%). Biopsy- compared with angiogram-confirmed cases had higher occurrences of cognitive impairment (55% vs 39%) and seizures (36% vs 16%), whereas focal neurologic signs occurred less often (56% vs 95%). CSF abnormalities were present in 75% vs 65% and MRI abnormalities in 97% vs 98% of patients. Digital subtraction angiography was positive in 33% of biopsy confirmed, and biopsy was positive in 8% of angiogram-confirmed cases. In 2 large cohorts, mortality was 23% and 8%, and the relapse rate was 30% and 34%, during a median follow-up of 19 and 57 months, respectively. There are no randomized trials on the treatment of PACNS. The initial treatment usually includes glucocorticoids and cyclophosphamide. Discussion PACNS is associated with disabling symptoms, frequent relapses, and significant mortality. Differences in symptoms and neuroimaging results and low overlap between biopsy and angiogram suggest that biopsy- and angiogram-confirmed cases represent different histopathologic types of PACNS. The optimal treatment is unknown.