Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Calciphylaxis ?
    ### Response:
    Calciphylaxis is a disease in which blood vessels (veins and arteries) become blocked by a build-up of calcium in the walls of the vessels, preventing blood from flowing to the skin or internal organs.  The lack of blood flow (ischemia) damages healthy tissue and causes it to die (necrosis).
    