Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Primary angiitis of the central nervous system ?
    ### Response:
    Primary angiitis of the central nervous system is a rare form of vasculitis (inflammation of blood vessels) affecting the blood vessels that nourish the brain, spinal cord and peripheral nerves. This condition can lead to narrowing and blockage of the blood vessels of the central nervous system which can eventually cause aneurysms, ischemia and/or hemmorrhage.
    