Varghese G M, Abraham O C, Mathai D, Thomas K, Aaron R, Kavitha M L, Mathai E
Christian Medical College, Vellore 632004, India.
J Infect. 2006 Jan;52(1):56-60. doi: 10.1016/j.jinf.2005.02.001.
To derive a clinical algorithm for diagnosis of scrub typhus among patients hospitalized with febrile illness and to determine predictors of bad prognosis.
Patients hospitalized with febrile illness of 5-30 days duration were evaluated for common aetiologies. Sera were tested for antibodies (IgM and IgG) to Orientia tsutsugamushi using ELISA kit.
Among 207 patients, 50 had elevated levels of IgM antibodies. The data of these patients were compared with that of 16 controls having febrile illnesses in whom rickettsial infection was ruled out. Transaminase elevation (>twice normal) was present in 90% and was significantly (P=0.004) more common in those with scrub typhus. If a combination of elevated transaminases, thrombocytopenia and leukocytosis is used, the specificity and positive predictive value are about 80%. Case fatality rate was 14%. Univariate analysis showed that hyperbilirubinemia (>1.5mg%) has a RR of 9 (95% CI=1.48-58.5) and elevated creatinine level (>1.4 mg%) had a RR of 43.99 (95% CI=3.65-530.5) for death. Elevated creatinine level was found to be an independent predictor of mortality (P=0.02).
In developing countries with limited diagnostic facilities, it is prudent to recommend empiric therapy in patients with undifferentiated febrile illness having evidence of multiple system involvement especially if there is transaminase elevation. Elevated creatinine may predict bad outcome.
推导用于诊断发热性疾病住院患者恙虫病的临床算法，并确定预后不良的预测因素。
对住院5至30天的发热性疾病患者评估常见病因。使用酶联免疫吸附测定试剂盒检测血清中针对恙虫病东方体的抗体（IgM和IgG）。
在207例患者中，50例IgM抗体水平升高。将这些患者的数据与16例已排除立克次体感染的发热性疾病对照患者的数据进行比较。90%的患者存在转氨酶升高（>正常上限两倍），且在恙虫病患者中更为常见（P=0.004）。若采用转氨酶升高、血小板减少和白细胞增多的联合指标，特异性和阳性预测值约为80%。病死率为14%。单因素分析显示，高胆红素血症（>1.5mg%）的死亡相对危险度为9（95%可信区间=1.48-58.5），肌酐水平升高（>1.4mg%）的死亡相对危险度为43.99（95%可信区间=3.65-530.5）。肌酐水平升高是死亡的独立预测因素（P=0.02）。
在诊断设施有限的发展中国家，对于有证据表明多系统受累的不明原因发热性疾病患者，尤其是存在转氨酶升高的患者，推荐经验性治疗是谨慎的做法。肌酐水平升高可能预示不良预后。
