血管炎性末梢神経障害の症候学と診断

Vasculitic Peripheral Neuropathies: Clinical Features and Diagnostic Laboratory Tests

血管炎性末梢神経障害は，血管炎による神経栄養血管の血行障害を背景として生じる末梢神経系の多発性虚血性梗塞である。四肢遠位優位の感覚・運動障害ないし感覚障害が生じ，痛みを伴うことが多い。典型的には多発性単ニューロパチーを呈するが，症候の分布も進展速度も多彩であり，注意深い病歴聴取と診察が必要である。診断には血管炎の証明が望ましいが，全身の炎症性症候や検査所見を参考にする。適切な治療を早期に開始するための速やかで的確な診断と，病勢および治療効果の評価には，精確な神経学的診察が肝要である。

Abstract

Vasculitic peripheral neuropathy (VPN) occurs due to ischemic changes of peripheral nerves, resulting from a deficit of vascular blood supply due to damaged vasa nervorum leading to vasculitis. VPN usually manifests as sensorimotor or sensory disturbances accompanied by pain, presenting as a type of multiple mononeuropathy, with a scattered distribution in distal limbs. VPN may also present as a mononeuropathy, distal symmetric polyneuropathy, plexopathy, or radiculopathy. The rapidity of VPN is variable, ranging from days to months, with symptoms occasionally changing with the appearance of new lesions. Careful history taking and neurological examination provides an exact diagnosis. The most common cause of VPN is primary vasculitis predominantly affecting small vessels, including vasa nervorum, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and polyarteritis nodosa. Similar vasculitic processes can also result from a systemic collagen disorder or secondary vasculitis. Electrophysiological studies and pathological investigation of biopsied peripheral nerves and muscles are important for diagnosis of vasculitis. Serological tests, including ANCA, are useful for diagnosis of vasculitis. Accurate neurological examinations are essential for diagnosis and evaluation of clinical course.