Primary central nervous system vasculitis and moyamoya disease: similarities and differences.

Primary central nervous system vasculitis (PCNSV) and moyamoya disease (MMD) represent rare and poorly-understood causes of stroke. Both may present with similar clinical and auxiliary findings, but differentiation is extremely important because they require different treatment regimens. Our cohort included 21 white patients with PCNSV and 21 white patients with MMD. Clinical and diagnostic features were obtained by retrospective chart review; follow-up information and outcome were obtained prospectively. Data were compared between patients with PCNSV and MMD using Chi square test or Fisher's exact test for categorical data and Mann-Whitney U test for continuous data. The mean age at symptom onset was 42.48 years in PCNSV and 31.0 years in MMD (p = 0.008). All patients with MMD presented with ischemic events while cerebral ischemia was observed in only 14 of 21 patients (66.7%) with PCNSV (p = 0.004). There was no significant difference regarding the frequency of headaches, which represented an important symptom in both conditions. Conventional cerebral angiography verified correct diagnosis in 13 of 17 patients (76.5%) with PCNSV while angiogram verified correct diagnosis in all patients with MMD (p = 0.032). MRI and cerebrospinal fluid studies were appropriate to differentiate between the inflammatory and the non-inflammatory disease. Three PCNSV patients and two MMD patients died within documented follow-up. Despite important pathophysiological and angiographic differences, PCNSV and MMD may present with similar clinical and auxiliary findings. An intensive workup including MRI, conventional cerebral angiography and CSF studies is required to avoid misdiagnosis.