OBJECTIVESBacterial musculoskeletal infections (MSKIs) are challenging to diagnose because of the clinical overlap with other conditions, including Lyme arthritis. We evaluated the performance of blood biomarkers for the diagnosis of MSKIs in Lyme disease-endemic regions. METHODSWe conducted a secondary analysis of a prospective cohort study of children 1 to 21 years old with monoarthritis presenting to 1 of 8 Pedi Lyme Net emergency departments for evaluation of potential Lyme disease. Our primary outcome was an MSKI, which was defined as septic arthritis, osteomyelitis or pyomyositis. We compared the diagnostic accuracy of routinely available biomarkers (absolute neutrophil count, C-reactive protein, erythrocyte sedimentation rate, and procalcitonin) to white blood cells for the identification of an MSKI using the area under the receiver operating characteristic curve (AUC). RESULTSWe identified 1423 children with monoarthritis, of which 82 (5.8%) had an MSKI, 405 (28.5%) Lyme arthritis, and 936 (65.8%) other inflammatory arthritis. When compared with white blood cell count (AUC, 0.63; 95% confidence interval [CI], 0.55-0.71), C-reactive protein (0.84; 95% CI, 0.80-0.89; P < .05), procalcitonin (0.82; 95% CI, 0.77-0.88; P < .05), and erythrocyte sedimentation rate (0.77; 95% CI, 0.71-0.82; P < .05) had higher AUCs, whereas absolute neutrophil count (0.67; 95% CI, 0.61-0.74; P < .11) had a similar AUC. CONCLUSIONSCommonly available biomarkers can assist in the initial approach to a potential MSKI in a child. However, no single biomarker has high enough accuracy to be used in isolation, especially in Lyme disease-endemic areas.

Background Enteral nutrition (EN) intolerance and delayed gastric emptying are prevalent in pediatric critical illness and limit EN delivery. Gastrointestinal (GI) hormones may be associated with EN intolerance and delayed gastric emptying in this cohort. Methods We determined GI hormone levels, time to achieve 50% of EN goal, and gastric emptying in critically ill children. Total amylin, active ghrelin, total glucagon-like peptide-1 (GLP-1), total gastric inhibitory polypeptide, glucagon, and total peptide-YY (PYY) were measured by multiplex assay and cholecystokinin by ELISA. Lower concentrations of acetaminophen at 1 hour (C1h, mu g/mL) using the acetaminophen absorption test defined delayed gastric emptying. Correlation, regression analyses, and a principal component analysis were used to examine the association between GI hormones and time to 50% EN goal and C1h. Results GI hormones were measured in 14 of 21 patients with gastric emptying testing; median age of 11.2 years (6.74-16.3) and 50% male. Increasing hormone levels from GI hormone profile 1 (GLP-1, glucagon, and amylin) correlated with greater time to reach 50% EN goal (R-2 = 0.296, P = 0.04). Decreasing hormone levels from GI hormone profile 2 (PYY and ghrelin) correlated with lower C1h and slower gastric emptying (R-2 = 0.342, P = 0.02). Conclusion GI hormone profiles are associated with time to achieve 50% of EN goal and gastric emptying in critically ill children. We have described a feasible model to study the role of GI hormones in this cohort, including the potential clinical applicability of GI hormone measurement in the management of delayed gastric emptying.