Discriminative Accuracy of Procalcitonin and Traditional Biomarkers in Pediatric Acute Musculoskeletal Infection

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Pediatric musculoskeletal infections

PURPOSE OF REVIEW

The aim of this article is to review the recent guidelines and literature regarding the diagnosis and the treatment of common pediatric musculoskeletal infections: septic arthritis, osteomyelitis, pyomyositis, and Lyme disease.

RECENT FINDINGS

In the last decade, a better understanding of the causative organisms of common bacterial infections, including Kingella , leads to prompt targeted antimicrobial coverage in all musculoskeletal infections. Prompt diagnosis and treatment continues to be the mainstay in the treatment of children with osteoarticular infections. Efforts to improve early detection have lead to improving rapid lab diagnostic testing; however, more advanced diagnostics such as arthrocentesis for septic arthritis and MRI for osteomyelitis and pyomyositis, remain the gold standard. Shorter and narrowed antibiotic courses, with appropriate transition to outpatient oral treatment provide effective infection clearance and reduction in complications of disease.

SUMMARY

Advances in diagnostics, including pathogen identification as well as imaging continues to improve our ability to diagnose and treat these infections, although still lack ability to provide definitive diagnosis without more invasive nor advanced techniques.

Comparison of Procalcitonin With Commonly Used Biomarkers and Algorithms for Evaluating Suspected Pediatric Musculoskeletal Infection in the Emergency Department

INTRODUCTION

It is difficult to distinguish between children with infectious versus noninfectious conditions of the musculoskeletal system during initial evaluation. Clinical predictive algorithms potentially support this effort but not without limitations. Procalcitonin (PCT) has been proposed as a biomarker to help differentiate infection from noninfection. This study evaluates the adoption and utility of PCT during initial infection evaluations and assesses test characteristics of commonly used parameters and algorithms.

METHODS

PCT was introduced for initial laboratory evaluation of the suspected musculoskeletal infection. Prospective enrollment occurred from July 2020 to November 2021 with 3 cohorts established after a retrospective review of final diagnoses at the end of treatment: 1) deep infection, 2) superficial infection, and 3) noninfection. Univariate and multivariate logistic regression analysis of parameters and diagnoses was performed. Test characteristics of individual and aggregated parameters were assessed.

RESULTS

Among 258 children evaluated, 188 (72.9%) had PCT drawn during the evaluation. An increase of PCT acquisition from 67.8% to 82.4% occurred over the study timeframe. Eighty-five children were prospectively studied, including those with deep infection (n=21); superficial infection (n=10), and noninfection (n=54). Test characteristics of parameters showed accuracy ranging from 48.2% to 85.9%. PCT >0.1 ng/mL independently predicted deep infection in 84.7% of cases, outperforming white blood cell, C-reactive protein (CRP), and absolute neutrophil count. Using study thresholds for CRP, erythrocyte sedimentation rate, PCT, and Temp improved accuracy to 89.4%.

CONCLUSIONS

PCT is a potentially useful biomarker during the initial assessment of children suspected to have a musculoskeletal infection. Systematic evaluation using a combination of parameters improves the accuracy of assessment and assists predictive judgment under uncertainty. PCT <0.1 ng/mL, erythrocyte sedimentation rate <18 mm/hr, CRP <3.3 mg/dL, and temperature <37.8°C should reasonably reassure clinicians that deep musculoskeletal infection is less likely, given the high negative predictive value and collective accuracy of these parameters.

LEVEL OF EVIDENCE

Level III - Retrospective cohort comparison.

Clinical Features and Etiology of Musculoskeletal Infection with or without Sepsis in the Emergency Department

Background

Musculoskeletal infection (MSKI) is a common reason to seek medical care in the emergency department (ED). We aimed to determine the clinical characteristics and etiology of patients with MSKI in our ED, the characteristics of MSKI with sepsis, and the predictors of death in sepsis patients.

Methods

The study retrospectively analyzed patients with MSKI from April 1, 2017, to March 31, 2021. The patients were divided into non-sepsis and sepsis groups. Clinical data of these patients including their basic information, laboratory results, diagnostic results, and outcomes were collected. Statistical analysis was carried out using GraphPad Prism 5.

Results

In all, 106 patients (70 male, 36 female) were enrolled in this study: 43 MSKI patients with sepsis and 63 MSKI patients without sepsis. Five patients with sepsis died. The patients’ age and sex ratio were no significantly different between the sepsis and non-sepsis groups. In the sepsis group, the ratio of rheumatic diseases, diabetes, coronary heart disease, and deep vein thrombosis was significantly different than that in the non-sepsis group (all p<0.05). Fifty-six patients (54.37%) had positive etiology results. Staphylococcus, streptococcus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli were the most common bacteria found in both groups, but sepsis patients had more Candida albicans infections than non-sepsis patients (p=0.0331, p<0.05). The five patients who died in the sepsis group had higher serum levels of creatinine and procalcitonin (PCT). Multivariate logistic regression analyses showed that PCT (p=0.026; odds ratio, 1.038) was significantly related to mortality.

Conclusion

In MSKI patients, rheumatic diseases, diabetes, coronary heart disease, and deep vein thrombosis are the risk factors for sepsis. Staphylococcus, streptococcus, K. pneumoniae, P. aeruginosa, and E. coli were the most common bacteria in MSKI patients, while MSKI patients with sepsis had more C. albicans infections. Elevated PCT was significantly related to death in sepsis patients.

Prospective Observational Study to Determine Kinetics of Procalcitonin in Hospitalized Children Receiving Antibiotic Therapy for Non-Critical Acute Bacterial Infections

INTRODUCTION

The kinetics of procalcitonin in pediatric patients with non-critical acute bacterial infections receiving appropriate antibiotic therapy are not well described.

METHODS

We performed a single-center, prospective observational pilot study of children admitted to a tertiary care children's hospital who were receiving antibiotics for treatment of a non-critical acute bacterial infection, and we prospectively measured serial procalcitonin levels daily for 4 days during hospitalization.

RESULTS

Among the 46 children with baseline procalcitonin levels enrolled in the study, procalcitonin kinetics followed a half-life of approximately 24 h in most patients. Procalcitonin declined faster than C-reactive protein over the first 48 h of appropriate antibiotic treatment. There was variation in biomarker levels among participants with the same infection type, especially in participants with bacteremia, musculoskeletal infection and skin/soft tissue infection.

CONCLUSION

Utility of procalcitonin as a biomarker to follow every 24-48 h in non-critically ill children receiving antibiotic therapy for bacterial infections as an objective measure of clinical improvement is promising.