Primary Angiitis of the CNS: Differences in the Profile Between Subtypes and Outcomes From an Indian Cohort.

Background and objectives: Primary angiitis of the CNS (PACNS) is a rare disease that has significant morbidity and mortality. Subtypes of PACNS can have different presentations that could be missed with certain diagnostic modalities, further increasing diagnostic complexity. We sought to distinguish the subtypes of PACNS and describe their outcomes in an Indian cohort.

Methods: Adult patients in this retrospective single-center cohort study were reviewed from the PACNS database between 2000 and 2019. Diagnosis was made as per Calabrese and Malleck criteria. Small and medium vessel vasculitis was defined, and their clinical and radiologic profile, treatment, and outcomes were compared. Functional outcomes were noted at 6-month, 1-year, and at last follow-up, while relapses were noted at last follow-up. A poor outcome was defined as modified Rankin Scale >2.

Results: Seventy-two patients fulfilled the inclusion criteria of whom 50 (69.4%) were male. The small vessel vasculitis subtype had a younger age at onset (30.5 vs 40.5 years, p = 0.014), presented less often as a stroke (22% vs 62%, p = 0.001), and had greater delay in diagnosis and treatment initiation (median of 620 days vs 118 days, p = 0.001) compared with medium vessel vasculitis subtype. Although no difference was noted at 6 months, the small vessel vasculitis group had poor outcomes at 1-year and last follow-up (57% vs 20%, p = 0.011 and 72% vs 34%, p = 0.005, respectively) and had more relapses at last follow-up (89% vs 30%, p < 0.001) when compared with the medium vessel vasculitis group. On analyzing the entire cohort, 50 of 72 (69%) and 37 of 53 (69.8%) patients had a good outcome at 6 months and 1 year, respectively. Relapse was noted in 35 of 72 (49%) at final follow-up. The choice of the treatment regimen did not predict outcomes or relapses.

Discussion: The small vessel vasculitis subtype of PACNS is a distinct entity that has diagnostic and treatment delays with poor long-term outcomes and more relapses. Recognizing the different subtypes of PACNS may help to expedite diagnosis and plan treatment.