一位表現為泌尿道感染的病例：困難診斷及不可忽視的顯微鏡下多血管炎

Challenging and Non-negligible Microscopic Polyangiitis: A Case Presenting with Urinary Tract Infection

顯微鏡下多血管炎(microscopic polyangiitis)是一種原因不明的自體免疫疾病，屬於抗嗜中性白血球細胞質自體抗體antineutrophil cytoplasmic autoantibody(ANCA)血管炎一種，其疾病的特色為小血管發生壞死性血管炎，病人血清常可測到ANCAs，最常見侵犯的器官為腎臟及肺臟。雖然常見的臨床表現為咳嗽、喘促咳血及肌肉痠痛或是關節疼痛，但是病人也可能以一些非特異性的全身性發炎症狀為臨床表現。本案例為70歲女性，之前有高血壓病史，此次因發燒、膿尿，診斷為泌尿道感染入院，但在使用抗生素治療後，病人仍持續發燒且全身無力情形，因為持續有血尿及蛋白尿情形進行腎臟切片檢查，確診為免疫缺少類型的腎絲球外局部增生型腎絲球腎炎，病人的細胞核周邊ANCA也呈現陽性，因此使用癌德星、類固醇和雙重血漿置換術治療，病人在退燒且全身無力改善後順利出院。

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides include granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. It has unknown etiology but it can be detected in patients’sera. The most involved organs are kidney and lung and the most common symptom is cough, dyspnea, hemoptysis, muscle soreness or arthralgia. However, unspecific symptoms have also been noted, including fever, body weight loss or poor appetite. Herein we reported a case involving a 70-year-old woman with hypertension admitted due to a fever that had lasted for one month. Because she presented pyuria, we diagnosed her as having a urinary tract infection and prescribed her empirical antibiotics. However, fever and general weakness persisted. Renal biopsy showed an extraglomerular focal proliferative glomerulonephritis, which is compatible with pauci-immune vasculitis. Serum perinuclear-ANCA was positive and microscopic polyangiitis was therefore diagnosed. The patient was prescribed an immunosuppressant agent with cyclophosphamide and prednisolone were prescribed and she also received double filtration plasmapheresis. After treatment, her fever subsided and general weakness resolved. She was discharged with improved condition.