The clinical features, pathology, and outcome of isolated (primary, idiopathic) angiitis of the CNS (IACNS) in two new and 8 previously reported cases are analysed at the Hospital for Sick Children, Toronto, Canada. Cases were grouped according to the size of arteries affected - 1) small or 2) large and medium:
Group 1. IACNS affected small vessels in 5 cases, including the 2 new cases. Onset of symptoms was gradual, with persistent headaches in 3, multifocal neurologic deficits (2), cognitive impairment (1), mood disorder (1), and focal seizures (3). Brain MRI was abnormal in all 5, showing a single tumor-like mass in 2. Angiography was abnormal in only 1, showing stenosis of a quaternary branch of the middle cerebral. Diagnosis was confirmed by CNS biopsy, showing a nongranulomatous (lymphocytic) vasculitis. Immunosuppression treatment with prednisone was successful in 4 who are alive without recurrence; 1 died at 18 months after presentation, despite the addition of cyclophosphamide in thgerapy.
Group 2. Large artery IACNS in 5 cases presented with ischemic stroke in 2, transient ischemic attacks (1), and subarachnoid hemorrhage (2). Four died within 10 days, and the fifth child had cerebral hematomas secondary to recurrent ruptured aneurysms. The wall of one resected aneurysm showed inflammatory infiltration, and this child died 7 years after presentation. All 5 at autopsy showed granulomatous infiltration and necrosis of large and medium vessels. Elevated ESR, inflammatory CSF, and abnormal angiograms are more frequent in group 2 patients. Clinical evaluation excluded other causes, including drug exposures, systemic infection, thromboembolism, and rheumatic disease. Patients with poor outcome had involvement of large and medium-sized arteries, presentation with acute stroke, granulomatous angiitis on brain biopsy, and delayed treatment with prednisone. 
COMMENT. Isolated, primary angiitis of the CNS in children may affect either small or large arteries. The clinical and radiological manifestations correlate with the size of vessel involved, and the outcome differs between groups. A poor outcome is more likely in cases presenting with acute stroke and disease of large arteries, granulomatous angiitis on biopsy, and delay in instituting immunosuppressive therapy. CNS involvement by systemic infection or rheumatic disease, including lupus erythematosus, should be considered in angiitis affecting small cerebral vessels.