台灣膿性肌炎病患的年齡分佈合併症及致病菌近似於非熱帶性膿性肌炎

Pyomyositis in Taiwan resembles nontropical pyomyositis in patient age distribution, comorbidities, and causative pathogens

研究目標：膿性肌炎是骨骼肌的一種化膿性感染，因為初期症狀不明顯以及不具特異性，容易被誤診為風濕性疾病。這個研究目的主要是要分析台灣膿性肌炎病患的致病危險因子、臨床表徵、實驗室數據及疾病病程，並與文獻中的膿性肌炎病例作比較。方法：從1996年4月至2005年12月期間，共有39位膿性肌炎病患住進台大醫院，我們分析其病歷作回溯性研究，並以單變數與多變數分析方式統計其死亡危險因子。結果：病人平均年齡為54.5±19.9歲（範圍為4.5-86歲），並沒有性別上的差異。糖尿病（38.5%）與外傷（20.5%）為最常見的致病危險因子。最常見的表現症狀依次為疼痛（87.2%）、發燒（79.5%）以及軟組織腫脹或腫塊形成（53.9%）。病患最初最常被誤診為蜂窩組織炎。三分之一的病患血液培養呈陽性。致病菌種以金黃色葡萄球菌（50%）最常見，其次為鏈球菌（20.8%）與革蘭氏陰性菌（20.8%）。61.5%的病患痊癒，但高達17.9%的病患死亡。在單變數分析中，血管內感染、鏈球菌感染與多重菌株感染為死亡的危險因子。而在多變數分析中，只有血管內感染與多重菌株感染為獨立的預後因子。結論：我們的膿性肌炎病患有高比例的合併症，並且有較高的死亡率，血管內感染與多重菌株感染為其獨立的死亡危險因子。

Objective. Pyomyositis, a disease characterized by suppuration within the skeletal muscle, is easily misdiagnosed as a rheumatic disease due to vague and nonspecific symptoms at presentation. The aim of this study was to analyze the predisposing factors, clinical characteristics, laboratory data, and disease course of patients with pyomyositis in Taiwan and compare with those cases reported in the literatures. Methods. We retrospectively reviewed medical records of 39 patients with pyomyositis admitted to National Taiwan University Hospital between April 1996 and December 2005 and assessed the risk factors for mortality by univariate and multivariate analyses. Results. The mean age of the patients was 54.5± 19.9 years (range, 4.5-86 years) with equal sex ratio. Diabetes mellitus (DM) (38.5%) and trauma (20.5%) were the most common predisposing factors. The leading presenting symptoms in orders were pain (87.2%), fever (79.5%), and soft tissue swelling or mass formation (53.9%). Cellulitis was the most common presumed diagnosis at presentation. Blood cultures were positive in one-third of the patients. The leading causative organism was Staphylococcus aureus (50%), followed by streptococcal species (20.8%) and gram-negative bacilli (20.8%). 61.5% of the patients recovered completely, while 17.9% died. Risk factors for mortality in the univariate analysis included intravascular, streptococcal, and polymicrobial infections. Intravascular and polymicrobial infections were the only two independent prognostic factors in the multivariate analysis. Conclusion. A high proportion of comorbidities and a higher mortality rate were found in our patients with pyomyositis. Intravascular and polymicrobial infections were the independent risk factors for mortality in these patients.