皮肌炎/多发性肌炎并发肺孢子虫肺炎的临床诊治

目的总结皮肌炎/多发性肌炎（DM/PM）患者并发肺孢子虫肺炎（PCP）的诊治经过,提高对该病的认识。方法对8例DM/PM患者（其中DM6例、PM2例）进行回顾性分析其并发PCP的危险因素、临床表现、影像学改变、治疗和转归。结果 8例患者中6例合并肺间质病变,均联合应用大剂量糖皮质激素和免疫抑制剂治疗。多数（6/8）诊断为DM/PM的患者在6个月内发生PCP,临床表现为发热、咳嗽和进行性呼吸困难;平均动脉血氧分压为44（40.7～66）mmHg（1mmHg=0.133kPa）;胸部影像学示双肺间质磨玻璃或多发弥漫斑片影。平均外周血淋巴细胞计数为0.46（0.16～0.76）×109/L,平均CD4＋T细胞计数为0.14（0.05～0.25）×109/L。3例患者痰中、4例患者支气管肺泡灌洗液中找到肺孢子虫,3例患者痰中肺孢子虫聚合酶链反应（PCR）阳性;4例患者合并其他病原体感染。8例患者均应用复方磺胺异噁唑和糖皮质激素治疗,死亡6例。结论 PCP为DM/PM患者少见,但其致命性、机会性感染在临床诊治时需提高警惕。

Pneumocystis Pneumonia in 8 Patients with Dermatomyositis/Polymyositis

Objective To determine the clinical features and the prognosis of pneumocystis pneumonia（PCP） in human immunodeficiency virus（HIV）-free patients with dermatomyositis/polymyositis（DM/PM）.Methods Retrospective analysis was used to investigate the clinical features and the outcome of PCP patients with DM/PM in single hospital.Results A total of 8 cases of PCP in patients with DM/PM were studied（dermatomyositis,n=6;polymyositis,n=2）.The majority of patients（6/8 patients,75%） presented PCP during the first 6 months following the diagnosis of DM/PM.At the time of diagnosis of PCP,all patients were receiving corticosteroids plus immunosuppressive agents（methotrexate,n=8;cyclophosphamide,n=1;azathiopurine,n=1;cyclosporine,n=1）.All patients were lymphocytopenic at the onset of PCP：the mean circulating lymphocytes count was 0.46（0.16~0.76）×109/L,mean CD4＋ lymphocyte count was 0.14（0.05~0.25）×109/L.The mean duration of prodromal symptoms was 10 days.Seventy-five percent patients required intensive care for respiratory failure.Mortality was high（6/8 patients,75%）.Conclusions PCP is an uncommon,but fatal opportunistic infection in patients with DM/PM.It must be considered in patients with DM/PM complicated with interstitial lung disease and receiving cytotoxic agents and corticosteroids,particularly if they have lymphocytopenia and/or CD4＋ lymphocyte count less than 0.25×109/L.Thus,induced sputum or bronchoalveolar lavage should be performed in patients with DM/PM when presenting with fever,pulmonary infiltrates,hypoxemia and lymphopenia.