ANCA関連血管炎によると考えられた下大静脈血栓症の1例

A Case of ANCA-associated Vasculitis with Total Thrombotic Occlusion of the Inferior Vena Cava

要旨　患者は64歳，男性．38歳時に両下肢の腫脹と疼痛にて近医で下肢静脈瘤と診断された．63歳時に症状が増悪したので当院に入院．下肢静脈造影にて大腿静脈から下大静脈にかけて血栓性に閉塞していたため抗凝固療法を行い症状が改善した．その後，経過中に移動性非区域性の間質性肺炎と関節炎を繰り返し自然に寛解した．凝固能には異常がなく，臨床所見からBehçet病は否定的であった．臨床症状に応じてC-ANCA，CRPの出現消褪を認め，鼻腔生検ではWegener肉芽腫に特徴的な肉芽腫は認めなかったが，ANCA関連血管炎と考えられた．細静脈炎により血栓が生じ，二次的に下大静脈に血栓形成が及んだものと考えられた．

　A 64-year-old man was admitted to our hospital presenting with swelling and pain in the lower extremities. Venography showed thrombotic occlusion from the bilateral femoral veins to the inferior vena cava. His symptoms resolved with anticoagulant therapy. Risk factors for hypercoagulability were not found. CT scan showed no invasion of tumors to the inferior vana cava. The absence of oral aphtous ulcer, genital ulcer or uveitis made Behcet disease unlikely. The patient developed non-segmental interstitial pneumonia and arthritis, and improved spontaneously. Interstitial pneumonia and arthritis recurred four months after his discharge. Laboratory test revealed C-ANCA as positive. Although the histological examination of the nasal mucosa did not support the diagnosis of Wegener's granuloma, we diagnosed ANCA-associated vasculitis. Thrombotic occlusion of the inferior vena cava occurred secondary to venulitis caused by ANCA-associated vasculitis.