From the Brown University, Providence, RI.
Division of Pediatric Emergency Medicine, Children's Hospital of Pittsburgh, Pittsburgh, PA.
Pediatr Emerg Care. 2022 Feb 1;38(2):e881-e885. doi: 10.1097/PEC.0000000000002455.
In Lyme disease endemic areas, Lyme and septic arthritis often present similarly. A published septic knee arthritis clinical prediction rule includes 2 high-risk predictors: absolute neutrophil count of 10,000 cells/mm3 or greater and erythrocyte sedimentation rate of 40 mm/h or greater. The objective of the study was to externally validate this prediction rule in a multicenter prospective cohort.
We enrolled a prospective cohort of children with knee monoarthritis undergoing evaluation for Lyme disease at 1 of 8 Pedi Lyme Net emergency departments located in endemic areas. We defined a case of septic arthritis with a positive synovial fluid culture or a synovial fluid white blood cell count of 50,000 or greater per high powered field with a positive blood culture and Lyme arthritis with a positive or equivocal C6 EIA, followed by a positive supplemental immunoblot. Other children were classified as having inflammatory arthritis. We report the performance of the septic arthritis clinical prediction rule in our study population.
Of the 543 eligible children, 13 had septic arthritis (2.4%), 234 Lyme arthritis (43.1%), and 296 inflammatory arthritis (54.5%). Of the 457 children (84.2%) with available laboratory predictors, all children with septic arthritis were classified as high risk (sensitivity, 100%; 95% confidence interval [CI], 77.2%-100%; specificity, 68.1%; 95% CI, 63.6-73.3; negative predictive value, 278/278 [100%]; 95% CI, 98.6%-100%). Of the 303 low-risk children, 52 (17.2%) underwent diagnostic arthrocentesis.
The septic knee arthritis clinical prediction rule accurately distinguished between septic and Lyme arthritis in an endemic area. Clinical application may reduce unnecessary invasive diagnostic procedures.
在莱姆病流行地区，莱姆病和脓毒性关节炎的表现常常相似。一份已发表的脓毒性膝关节关节炎临床预测规则包括 2 个高危预测因素：白细胞绝对计数 10,000 个/立方毫米或更高，红细胞沉降率 40 毫米/小时或更高。本研究的目的是在多中心前瞻性队列中对该预测规则进行外部验证。
我们招募了一个前瞻性队列，该队列包括在 8 个 Pedi Lyme Net 急诊部门中的 1 个进行莱姆病评估的膝关节单关节炎患儿。我们将以下情况定义为脓毒性关节炎：关节液培养阳性或关节液白细胞计数每高倍视野 50,000 个或更高，同时伴有血培养阳性和莱姆关节炎，或 C6 EIA 阳性或不确定，随后补充免疫印迹阳性。其他儿童被归类为炎症性关节炎。我们报告该脓毒性关节炎临床预测规则在我们的研究人群中的表现。
在 543 名符合条件的儿童中，有 13 名患有脓毒性关节炎（2.4%），234 名患有莱姆关节炎（43.1%），296 名患有炎症性关节炎（54.5%）。在 457 名（84.2%）有可用实验室预测因素的儿童中，所有脓毒性关节炎患儿均被归类为高危（敏感性，100%；95%置信区间[CI]，77.2%-100%；特异性，68.1%；95%CI，63.6-73.3；阴性预测值，278/278[100%]；95%CI，98.6%-100%）。在 303 名低危儿童中，有 52 名（17.2%）接受了诊断性关节穿刺术。
在流行地区，脓毒性膝关节关节炎临床预测规则准确地区分了脓毒性关节炎和莱姆关节炎。临床应用可能会减少不必要的有创性诊断程序。
