Central Nervous System (CNS) vasculitis is an inflammatory brain disease targeting the blood vessels of the brain and/or spinal cord. In this disease, cells of the immune system attack the brain blood vessel walls, which leads to swelling and damage of the wall itself and the surrounding brain tissue. Patients may experience seizures, headaches or difficulties with memory, behaviour or cognition. In some patients, the vessel wall swelling is so severe that it causes critically low blood supply to the brain tissue fed by this vessel. Clinically the patients may be then experiencing stroke-like symptoms or suffer an ischemic or hemorrhagic stroke. In addition, the inflamed and swollen wall may become "sticky", which increases the risk of clotting and further reduced blood flow through the affected vessel. 

• Seizures and intractable seizure status
• Headaches
• Stroke or other severe focal neurological deficits including impaired vision, speech deficits or movement abnormalities
• Severe diffuse deficits such as memory difficulties, cognitive dysfunction or behaviour problems
• Psychiatric symptoms such as hallucinations
• Fluctuating level of consciousness 

Inflammation can target different structures in the brain and/or spinal cord. In CNS vasculitis, the inflammation targets the blood vessels in the central nervous system. The spectrum of non-vasculitic inflammatory brain diseases is constantly expanding; it includes antibody-mediated inflammatory brain diseases such as anti-NMDA receptor encephalitis, demyelinating diseases such as multiple sclerosis (MS), primary T-cell mediated parenchymal inflammatory brain diseases such as Rasmussen's encephalitis, and granulomatous inflammatory brain diseases such as neurosarcoidosis.

Non-vasculitic inflammatory brain diseases criteria:

1. Any newly acquired neurological and/or psychiatric deficit
2. Evidence of an inflammatory brain disease in childhood, including:
   1. Auto-antibodies (NMDAR, Channel antibodies such as VGKC in limbic encephalitis, anti-aquaporin4 water channels in NMO, anti-neuronal enzyme antibodies such as GAD, OMS antibodies)
   2. Brain biopsy evidence of CNS inflammation other than small-vessel vasculitis
   3. Evidence of a positive post-infectious serology such as IgM for mycoplasma in the CSF with or without corresponding neuroimaging features
   4. Strong supportive evidence of CNS inflammation on spinal tap and/or MRI with subsequent immunosuppressive therapy