Acute Hematogenous Bacterial Osteoarticular Infections in Children

Clinical Utility of Repeat Magnetic Resonance Imaging Studies Among Children With Acute Hematogenous Osteomyelitis

BACKGROUND AND OBJECTIVES

There is limited guidance for whether repeat magnetic resonance imaging (MRI) studies are clinically impactful among children with acute hematogenous osteomyelitis (AHO) who fail to improve as expected. This study aimed to determine whether repeat MRIs changed management among children with AHO and identify clinical characteristics predictive of which patients benefit from repeat MRIs.

METHODS

Children admitted to a quaternary care pediatric hospital with AHO were identified during a 9-year period. Patients with chronic symptoms, non-hematogenous infections, or significant contributing comorbidities were excluded. Medical records were retrospectively reviewed for all MRIs performed 3 weeks before admission to 24 months after discharge. An MRI was considered clinically impactful if it identified a new infectious process (eg, abscess not seen on the initial MRI) or if it resulted in surgical intervention within 24 hours. Bivariable comparisons of categorical variables were performed, and multivariable logistic regression was used to assess the clinical factors of impactful repeat MRIs.

RESULTS

Among the 239 included patients, 41 (17%) had more than 1 MRI performed during their clinical course, the majority of whom (53.7%) had a repeat MRI that impacted care. Patients who underwent repeat MRIs had longer hospitalizations (7 vs. 5 d, P <0.01), were more likely to have C-reactive protein (CRP) levels >20 mg/dL (41% vs. 10%, P <0.01), and were more likely to have a delayed transition to oral antimicrobials (8.4 vs. 3.3 d, P <0.01). Peak CRP >20 mg/dL and prolonged bacteremia were found to be associated with increased odds of having an impactful repeat MRI, with adjusted odds ratios of 3.9 ( P =0.007) and 3.4 ( P =0.03), respectively.

CONCLUSIONS

When used judiciously among ill children with complicated AHO, repeat MRI can be clinically impactful. Prospective studies are needed to better define which children with AHO benefit from repeat MRI.

LEVEL OF EVIDENCE

Level II evidence-this is a retrospective cohort study interested in determining the clinical utility of repeat magnetic resonance imaging studies for children with osteomyelitis.

Correlation between the results of cultures and the molecular BIOFIRE® joint infection panel in a cohort of pediatric patients with bone and joint infections in Bogotá, Colombia

Introduction

Bone and Joint Infections (BJI) have high morbidity. Methicillin resistant Staphylococcus aureus (MRSA) has increased. Culture-based diagnosis has difficult to recovering fastidious bacteria and detecting polymicrobial infections, molecular methods offer a promising improvement for the diagnosis of BJI with reduced time to result. The aim of the study was to determine the correlation between culture results and the Biofire joint infection panel (BJIP) in a cohort of pediatric patients with BJI.

Materials and methods

Descriptive study. Patients admitted with probable o confirmed BJI between July 1, 2019 and February 28, 2021 at HOMI. Blood cultures, synovial and bone fluid samples were taken. Samples were kept at -70 °C. On September 2022, the panel was performed.

Results

32 patients were included. The average age was 83m (RIQ: 32-145). 23 (71.8%) patients had a positive culture. The most frequent microorganism were S. aureus 19 (83%), 11/19 (57.9%) Staphylococci isolates were MRSA. 24/32 (75%) were positive by panel, 20 positive detections were concordant with culture, there were 6 additional isolates by panel (2 S. aureus, 2 S. pyogenes, 1 K. kingae and 1 C. albicans), three microorganisms were isolated in culture but not in the panel. (2 S. aureus and 1 S. agalactiae). Two patients with coinfection were detected. All MRSA were detected by culture and panel. In 26 (81.3%) patients the etiology was documented by any method.

Conclusion

These results showed a moderate level of agreement between BJIP and culture (κ = 0.47). The panel allowed the detection of fastidious bacteria including K. kingae and polymicrobial samples. There was a very good level of agreement between the panel and culture for the MRSA detection (κ = 1).

Red blood cell distribution width as a potential inflammatory marker in pediatric osteomyelitis

Background

Red cell distribution width (RDW) has been used in the differential diagnosis of anemia and revealed to be a potential marker of inflammation.

Method

We conducted a retrospective study of acute-phase reactant changes in correlation with RDW among pediatric patients with osteomyelitis.

Results

We identified 82 patients whose mean RDW increased on average by 1% during antibiotic therapy (mean 13.9% on admission, 95% CI 13.4-14.3, and 14.9% at the end of antibiotic therapy, 95% CI 14.5-15.4). Overall, the RDW was weakly correlated with absolute neutrophil count (r = -0.21, P = 0.001), erythrocyte sedimentation rate (r = -0.17, P = 0.007), and C-reactive protein (r = -0.21, P = 0.001). The generalized estimating equation model showed a weak negative correlation between RDW and C-reactive protein during the therapy duration (B= -0.03, P = 0.008).

Conclusions

The mild increase in RDW, and its weak negative correlation with other acute-phase reactants during the study course, limits its utility as a therapy response marker in pediatric osteomyelitis.

Using Administrative Billing Codes to Identify Acute Musculoskeletal Infections in Children

BACKGROUND AND OBJECTIVES

Acute hematogenous musculoskeletal infections (MSKI) are medical emergencies with the potential for life-altering complications in afflicted children. Leveraging administrative data to study pediatric MSKI is difficult as many infections are chronic, nonhematogenous, or occur in children with significant comorbidities. The objective of this study was to validate a case-finding algorithm to accurately identify children hospitalized with acute hematogenous MSKI using administrative billing codes.

METHODS

This was a multicenter validation study using the Pediatric Health Information System (PHIS) database. Hospital admissions for MSKI were identified from 6 PHIS hospitals using discharge diagnosis codes. A random subset of admissions underwent manual chart review at each site using predefined criteria to categorize each admission as either "acute hematogenous MSKI" (AH-MSKI) or "not acute hematogenous MSKI." Ten unique coding algorithms were developed using billing data. The sensitivity and specificity of each algorithm to identify AH-MSKI were calculated using chart review categorizations as the reference standard.

RESULTS

Of the 492 admissions randomly selected for manual review, 244 (49.6%) were classified as AH-MSKI and 248 (50.4%) as not acute hematogenous MSKI. Individual algorithm performance varied widely (sensitivity 31% to 91%; specificity 52% to 98%). Four algorithms demonstrated potential for future use with receiver operating characteristic area under the curve greater than 80%.

CONCLUSIONS

Identifying children with acute hematogenous MSKI based on discharge diagnosis alone is challenging as half have chronic or nonhematogenous infections. We validated several case-finding algorithms using administrative billing codes and detail them here for future use in pediatric MSKI outcomes.

Identifying predictors for source culture positivity in children with acute musculoskeletal infections

OBJECTIVES

Identifying the causative bacterial pathogen for children with acute hematogenous musculoskeletal infections (MSKIs) allows for improved care. The purpose of our study was to determine if clinical markers could predict which patients will have a causative pathogen found on source culture alone, thus being highest yield to undergo operative diagnostic procedures.

METHODS

A single-center, retrospective cohort study was performed. Medical records for patients between 6 months and 18 years of age admitted between July 2014 and September 2018 with a discharge diagnosis of acute osteomyelitis, septic arthritis, or pyomyositis were reviewed. Patients were stratified based on results of blood and source cultures. Predictors of interest were screened on a univariable basis with significant predictors retained in a multivariate analysis.

RESULTS

There were 170 patients included. No predictors were significantly associated with increased odds of having a causative pathogen found on source culture alone. Degree of C-reactive protein elevation and history of fever were associated with decreased odds of being source culture positive, OR (95% CI); 0.92 (0.87, 0.98) and 0.39 (0.19, 0.81), respectively.

CONCLUSIONS

Predictive modeling failed to identify children with MSKIs whose causative pathogen was found by source culture alone. It is difficult to predict which MSKI patients will be highest yield for operative diagnostic procedures.

Characteristics of Children With Culture Negative Acute Hematogenous Musculoskeletal Infections

BACKGROUND

Identifying the causative pathogen for acute hematogenous musculoskeletal infections (MSKIs) allows for directed antimicrobial therapy and diagnostic confidence. However, 20% to 50% of children with acute MSKIs remain culture negative. The objective of this study was to compare characteristics of culture negative MSKI patients to those where a pathogen is identified.

METHODS

Electronic medical records of children admitted between July 2014 to September 2018 to a single quaternary care pediatric hospital with acute MSKIs were retrospectively reviewed. Clinical and demographic characteristics were compared between culture positive and culture negative MSKIs.

RESULTS

A total of 170 patients were included of whom 43 (25%) were culture negative. All culture negative patients had at least 1 culture type obtained, and the majority (84%) had both blood and source cultures performed. When compared with patients with a causative pathogen identified, culture negative patients were younger (2.3 vs. 9.8 y), smaller (13.5 vs. 31.6 kg), less likely to be febrile on arrival (56% vs. 77%), less likely to have an abscess on imaging (23% vs. 48%), and were more likely to have uncomplicated septic arthritis (35% vs. 8%). No critically ill patient was culture negative. Seven culture negative patients had additional Kingella kingae testing performed, none of which were positive.

CONCLUSIONS

Despite targeted and standardized efforts to identify causative bacteria, 25% of children with acute MSKIs never have a pathogen identified. Culture negative patients are younger, less febrile, are less likely to have an abscess, and more likely to have isolated septic arthritis.

LEVEL OF EVIDENCE

This is a retrospective cohort study interested in identifying patient characteristics that predict rate of culture positivity for acute MSKIs. This study meets criteria for Level II evidence.

Late sequelae of osteoarticular infections in pediatric patients: A single-center study

To review the orthopedic sequelae of pediatric patients diagnosed with osteoarticular infections (OAIs) and identify significant differences between those with and without sequelae. Medical charts between 2010 and 2016 from a tertiary-care pediatric hospital were reviewed to collect demographic and clinical data for this retrospective case series. The main inclusion criteria were: 1. age (≤10 years old); 2. absence of sickle cell anemia and immunocompromising disease or medication; 3. a minimum follow-up of 12 months with radiographs; and 4. diagnosis of osteomyelitis of long bones and/or septic arthritis. The following late sequelae were observed and aggregated: osteal deformations that led to limb-length discrepancies (LLD) superior to 5 mm, abnormal articular angulations of more than 5°, and symptomatic chondropathies visible on imaging studies after 1 year. The patients were divided into 2 subgroups: with and without sequelae. Chi-Squared tests were used for categorical variables and Mann–Whitney U tests for continuous data to identify statistically significant differences between the 2 subgroups. Among 401 patients with osteomyelitis and/or septic arthritis, 50 (12.5%) were included (24 girls and 26 boys). There were 36 (72%) cases of osteomyelitis, 8 (16%) cases of septic arthritis, and 6 (12%) cases of combined infection (3 acute/subacute and 3 chronic cases). Five (10%) patients had orthopedic sequelae at the latest follow-up. The total duration of antibiotic treatment (P = .002), infectious disease follow-up (P = .002), and the presence of sequestra (P = .005) were significantly different between subgroups. There were no statistically significant differences between the 2 subgroups for the other variables, but some trends could be discerned. Only 4/50 patients developed a sequestrum, 2 of which were in the orthopedic sequelae subgroup. Furthermore, initial C-reactive protein (CRP) values were higher in the sequelae subgroup, as were the CRP values at hospital discharge. The orthopedic follow-up was also longer in the sequelae subgroup. Finally, the delay between the onset of symptoms and the beginning of antibiotic treatment was longer in the sequelae group. Patients with orthopedic sequelae had a longer antibiotic treatment and infectious disease follow-up, and were more likely to have presented with a sequestrum. Level of evidence: IV – case series.