Systemic and non-systemic vasculitis affecting the peripheral nerves.

Vasculitis affecting the peripheral nerves predominantly manifests as subacute, progressive, asymmetric sensorimotor polyneuropathy or mononeuritis multiplex, and more rarely as painful mononeuropathy, pure sensory neuropathy, neuropathy of the cranial nerves, plexopathy, or as autonomic neuropathy. Vasculitic neuropathy may occur isolated or non-isolated (systemic) together with involvement of other organs. Systemic vasculitis with involvement of the peripheral nerves is further subdivided into primary (Takayasu syndrome, giant cell arteritis, classical panarteritis nodosa, thrombangitis obliterans, Kawasaki disease, Churg-Strauss syndrome, Wegener granulomatosis, cryoglobulinemic vasculitis, Behcet disease, microscopic polyangitis, Schoenlein Henoch purpura) or secondary systemic vasculitis (autoimmune connective tissue diseases, vasculitis from infection, sarcoidosis, malignancy, drugs, radiation, or diabetes). In addition to routine laboratory investigations and nerve conduction studies, nerve biopsy is essential for diagnosing the condition and to delineate it from differentials, although its sensitivity is only approximately 60%. Therapy of non-viral vasculitic neuropathy is based on corticosteroids and cyclophosphamide alone or in combination. Additional options include azathioprine, methotrexate, mycophenolate mofetil, or rituximab. In single cases immunoglobulins, immunoadsorbtion, or plasma exchange have been successfully applied. In case of virus-associated vasculitis interferon-alpha plus lamivudine or ribaverin may be beneficial.