Pediatric musculoskeletal infection: trends and antibiotic recommendations

Comparison of diagnosis and treatment of MSSA and MRSA osteomyelitis in children: a case-control study of 64 patients

BACKGROUND

We aimed to compare the clinical characteristics of acute osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) in children.

METHODS

We retrospectively analyzed the data of 64 children treated between September 2017 and June 2021. Based on the bacterial culture results, they were divided into MRSA and MSSA infection groups. Both groups were treated with debridement and vacuum-assisted closure for negative pressure drainage. Parameters including clinical manifestations, number of operations, length of hospital stay, inflammatory indicators, and concurrent arthritis were compared between the two groups.

RESULTS

In the MRSA infection group, there was one case each of residual joint stiffness and pathological fracture. Conversely, the MSSA group had two cases of residual joint stiffness. The MRSA infection group was more prone to high fever (t = 3.61, P = 0.001), white blood cell count elevation (t = 2.41, P = 0.022), arthritis (X² = 7.48, P = 0.013), metastatic abscess (X² = 4.78, P = 0.042), and a shorter length of progression from onset to admission (t = - 2.04, P = 0.046); however, it required more surgeries (t = 2.68, P = 0.009) and longer hospital stay (t = 2.04, P = 0.045).

CONCLUSIONS

Pediatric acute osteomyelitis caused by MRSA is more prone to cause high fever and markedly elevated of white blood cell count, and is often accompanied with suppurative infection of adjacent joints and metastatic abscesses, thus requiring more surgeries and longer hospital stay.

Surgical treatment of septic arthritis of the hip in children: arthrotomy compared with repeated aspiration-lavage

PURPOSE

To review two cohorts of children treated by two different protocols (repeated needle aspiration-lavage vs. arthrotomy) for surgical treatment of septic arthritis of the hip (SAH).

METHODS

In order to compare between the two methods, the following parameters were checked: (a) Scar cosmesis was assessed by the Patient and Observer Scar Assessment Scale (POSAS). We considered satisfactory results (no scar discomfort) when POSAS was within 10% of the ideal score; (b) 24-h post-operative pain was evaluated by visual analog scale (VAS); (c) Complication rates of incomplete drainage (re-arthrotomy/therapy modification from aspiration-lavage to arthrotomy). The results were evaluated by the Student t-test or by the chi-square test.

RESULTS

Seventy-nine children (aged 2-14 years) admitted during 2009-2018 and available for at least two years of follow-up were enrolled. The POSAS score (range 12-120 points) at the latest follow-up was higher in the arthrotomy group compared with the aspiration-lavage group (18.10 ± 6.22 versus 12.27 ± 1.40, p < 0.001); 77.4% of patients treated by arthrotomy had no scar discomfort. The 24-h post-intervention VAS (range 1-10) was 5.06 ± 1.29 after arthrotomy and 4.03 ± 1.13 after aspiration-lavage, p < 0.04. Complications were three times more frequent in the aspiration-lavage group (8.8% in the arthrotomy group and 26.7% in the aspiration-lavage group, p = 0.045).

CONCLUSIONS

We conclude that the lower complication rate observed in the arthrotomy group outweighs by far scar cosmesis and post-operative pain advantages in the aspiration-lavage group. Arthrotomy as a drainage method is safer than aspiration-lavage.

Institutional performance and validation of severity of illness score for children with acute hematogenous osteomyelitis

A scoring system has recently been published that uses parameters within the first 4-5 days of hospitalization to determine the severity of illness (SOI) in children with acute hematogenous osteomyelitis (AHO). To our knowledge, no additional studies to date have examined the validity of the SOI score outside of the institution of origin. This study evaluates the performance of the SOI score in a retrospective cohort of cases at our institution. Patients admitted to our institution over the past 5 years with AHO who met inclusion and exclusion criteria were analyzed. Parameters including C reactive protein over the first 96 h of hospitalization, febrile days on antibiotics, ICU admission, and presence of disseminated disease were used to calculate the SOI score for each patient. Pearson and Spearman correlations were used when appropriate. SOI score comparison between groups was achieved with the Kruskal-Wallis and Wilcoxon two-sample tests. Seventy-four patients were analyzed. Significantly higher SOI scores were noted for patients with bacteremia, ICU admission, fever for two or more days on presentation, multiple surgeries, and any complication. Markers of disease severity that significantly correlated with SOI score were total length of stay, LOS, duration of antibiotic course, number of surgical procedures, and case mix index. The SOI score functioned well as higher scores were associated with sicker patients. The SOI score is helpful for determining which patients will require longer hospitalizations and more intense treatment in a setting other than the institution of origin.

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.

Antibiotic-impregnated calcium sulfate for the treatment of pediatric hematogenous osteomyelitis

BACKGROUND

Antibiotic-impregnated calcium sulfate has excellent curative efficacy in chronic osteomyelitis. However, its curative efficacy in pediatric hematogenous osteomyelitis has not been sufficiently studied. The purpose of this study was to evaluate the curative effects of antibiotic-impregnated calcium sulfate in the treatment of pediatric hematogenous osteomyelitis.

METHODS

Overall, twenty-one pediatric patients with hematogenous osteomyelitis treated at our hospital between 2013 and 2018 were included for assessment. The clinical history, clinical manifestation, infection recurrence rate, sinus leakage, incision leakage, pathological fractures, bone growth and surgical procedures were analyzed.

RESULTS

The infection recurrence rate was 0% (0/21) at a minimum of 31 months (range 31 to 91 months) of follow-up. Postoperative incision leakage was found in one pediatric patient. Osteolysis was found in one pediatric patient. Acceleration of bone growth occurred in one pediatric patient. Retardation of bone growth occurred in one pediatric patient. Genu valgus deformity occurred in one pediatric patient.

CONCLUSIONS

Although noninfectious complications occurred, the curative effect of antibiotic-impregnated calcium sulfate in pediatric hematogenous osteomyelitis was satisfactory.

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.

A comparison of the vancomycin calcium sulfate implantation versus fenestration decompression for the treatment of sclerosing osteomyelitis

OBJECTIVE

To compare the clinical efficacy of vancomycin calcium sulfate implantation and fenestration decompression in the treatment of sclerosing osteomyelitis.

METHOD

A retrospective analysis for 46 cases of sclerosing osteomyelitis were admitted to our department between June 2010 to June 2020. Twenty-one patients were treated with fenestration decompression, twenty-five patients were treated with vancomycin calcium sulfate implantation. The postoperative hospital stay, days of drainage tube placement, visual analogue scale scores, C-reactive protein and erythrocyte sedimentation rate were compared between the two groups.

RESULTS

The visual analogue scale scores of both groups were significantly lower than before treatment (p < 0.05), but the difference between them was not statistically significant. Patients treated by vancomycin calcium sulfate implantation had shorter postoperative hospital stay and days of drainage tube placement compared to those treated by fenestration decompression (p < 0.05). C-reactive protein and erythrocyte sedimentation rate in both groups were significantly lower than before treatment, but the improvement effect of vancomycin calcium sulfate implantation was better (p < 0.05).

CONCLUSION

Both treatment methods can relieve pain effectively. Compared with fenestration decompression, vancomycin calcium sulfate implantation can shorten the treatment time effectively, control the infection better.

Long-Term Impact of a Clinical Care Guideline for Pediatric Acute Musculoskeletal Infections: Are Improved Outcomes Sustainable?

BACKGROUND

Acute hematogenous musculoskeletal infections are a common cause of hospitalization in children. A locally developed clinical care guideline (CCG) for acute musculoskeletal infections was implemented at our quaternary care pediatric hospital in July 2012. The purpose of this study was to evaluate the long-term sustainability of previously described improvements after CCG implementation.

METHODS

Clinical outcomes for children hospitalized with musculoskeletal infections at Children's Hospital Colorado from June 2009 through September 2018 were retrospectively reviewed. Patients were included if they had an International Classification of Diseases, Ninth Revision or International Classification of Diseases, 10th Revision discharge diagnosis of acute osteomyelitis, septic arthritis, or pyomyositis and were between 6 months and 18 years of age at admission. Patients with underlying medical complexity or nonhematogenous musculoskeletal infections were excluded. Patients were categorized by date of admission as either "pre-CCG" (June 2009 to June 2011) or "sustain-CCG" (July 2014 to September 2018). Primary outcomes were hospital length of stay and intravenous antimicrobial length of therapy.

RESULTS

From pre-CCG to sustain-CCG, median length of stay decreased by 1.29 days (5.56 vs 4.27; P < .004) and median length of therapy decreased by 5.04 days (8.33 vs 3.29; P < .0001). Statistical process control charts support that these were sustained improvements many years after CCG implementation. Additional secondary clinical improvements were observed in the sustain-CCG group including faster fever resolution, more consistent blood and source culture acquisition, and decreased central line placement. There was no increase in related readmissions or therapeutic failures in the sustain-CCG group.

CONCLUSIONS

Implementation of a CCG to standardize care for musculoskeletal infections can be sustained many years after implementation.

The Heterogeneity of Pediatric Knee Infections: A Retrospective Analysis

BACKGROUND

Musculoskeletal infection is a major cause of morbidity in the pediatric population. Despite the canonical teaching that an irritable joint and signs of infection likely represent an infected joint space, recent evidence in the pediatric hip has demonstrated that alternative diagnoses are equally or more likely and that combinations of pathologies are common. The knee is the second most commonly infected joint in children, yet there remains a paucity of available data regarding the epidemiology and workup of the infected pediatric knee. The authors hypothesize that there is heterogeneity of pathologies, including combinations of pathologies, that presents as a potentially infected knee in a child. The authors aim to show the utility of magnetic resonance imaging and epidemiologic and laboratory markers in the workup of these patients.

METHODS

A retrospective review of all consults made to the pediatric orthopaedic surgery team at a single tertiary care center from September 2009 through December 2015 regarding a concern for potential knee infection was performed. Excluded from the study were patients with penetrating trauma, postoperative infection, open fracture, no C-reactive protein (CRP) within 24 hours of admission, sickle cell disease, an immunocompromised state, or chronic osteomyelitis.

RESULTS

A total of 120 patients were analyzed in this study. There was marked variability in pathologies. Patients with isolated osteomyelitis or osteomyelitis+septic arthritis were older, had an increased admission CRP, were more likely to be infected with Staphylococcus aureus, required an increased duration of antibiotics, and had an increased incidence of musculoskeletal complications than patients with isolated septic arthritis.

CONCLUSIONS

When considering a child with an irritable knee, a heterogeneity of potential underlying pathologies and combinations of pathologies are possible. Importantly, the age of the patient and CRP can guide a clinician when considering further workup. Older patients with a higher admission CRP value warrant an immediate magnetic resonance imaging, as they are likely to have osteomyelitis, which was associated with worse outcomes when compared with patients with isolated septic arthritis.

LEVEL OF EVIDENCE

Level III-retrospective research study.

Concurrent Local Delivery of Diflunisal Limits Bone Destruction but Fails To Improve Systemic Vancomycin Efficacy during Staphylococcus aureus Osteomyelitis

Staphylococcus aureus osteomyelitis is a debilitating infection of bone. Treatment of osteomyelitis is impaired by the propensity of invading bacteria to induce pathological bone remodeling that may limit antibiotic penetration to the infectious focus. The nonsteroidal anti-inflammatory drug diflunisal was previously identified as an osteoprotective adjunctive therapy for osteomyelitis, based on the ability of this compound to inhibit S. aureus quorum sensing and subsequent quorum-dependent toxin production. When delivered locally during experimental osteomyelitis, diflunisal significantly limits bone destruction without affecting bacterial burdens. However, because diflunisal's "quorum-quenching" activity could theoretically increase antibiotic recalcitrance, it is critically important to evaluate this adjunctive therapy in the context of standard-of-care antibiotics. The objective of this study is to evaluate the efficacy of vancomycin to treat osteomyelitis during local diflunisal treatment. We first determined that systemic vancomycin effectively reduces bacterial burdens in a murine model of osteomyelitis and identified a dosing regimen that decreases bacterial burdens without eradicating infection. Using this dosing scheme, we found that vancomycin activity is unaffected by the presence of diflunisal in vitro and in vivo Similarly, locally delivered diflunisal still potently inhibits osteoblast cytotoxicity in vitro and bone destruction in vivo in the presence of subtherapeutic vancomycin. However, we also found that the resorbable polyester urethane (PUR) foams used to deliver diflunisal serve as a nidus for infection. Taken together, these data demonstrate that diflunisal does not significantly impact standard-of-care antibiotic therapy for S. aureus osteomyelitis, but they also highlight potential pitfalls encountered with local drug delivery.

Declining Prevalence of Methicillin-Resistant Staphylococcus aureus Septic Arthritis and Osteomyelitis in Children: Implications for Treatment

This study sought to assess clinical characteristics and differences in outcomes between children with Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) osteomyelitis or septic arthritis and whether initial antibiotic regimen affects patient outcomes. We analyzed records of children ages 15 days to 18 years admitted between 2009 and 2016 to two tertiary children's hospitals who were diagnosed with an osteoarticular infection and had a microorganism identified. A total of 584 patients met inclusion criteria, of which 365 (62.5%) had a microbiological diagnosis. MSSA was the most common pathogen identified (45.5%), followed by MRSA (31.2%). Compared to MSSA, patients with MRSA had a higher initial C-reactive protein and longer hospitalization. Patients whose initial antibiotic regimens included vancomycin had a longer hospitalization than those initiated on clindamycin without vancomycin, even after removing sicker patients admitted to the pediatric intensive care unit. While MRSA was associated with increased severity of osteoarticular infections compared to MSSA, the incidence of MRSA has been declining at our institution. Patients with longer lengths of stay were more likely to be on vancomycin. Clindamycin should be considered in the initial antibiotic regimen for osteomyelitis and septic arthritis with ongoing surveillance of local microbiology and outcomes.

Mechanisms of Immune Evasion and Bone Tissue Colonization That Make Staphylococcus aureus the Primary Pathogen in Osteomyelitis

PURPOSE OF REVIEW

Staphylococcus aureus is the primary pathogen responsible for osteomyelitis, which remains a major healthcare burden. To understand its dominance, here we review the unique pathogenic mechanisms utilized by S. aureus that enable it to cause incurable osteomyelitis.

RECENT FINDINGS

Using an arsenal of toxins and virulence proteins, S. aureus kills and usurps immune cells during infection, to produce non-neutralizing pathogenic antibodies that thwart adaptive immunity. S. aureus also has specific mechanisms for distinct biofilm formation on implants, necrotic bone tissue, bone marrow, and within the osteocyte lacuno-canicular networks (OLCN) of live bone. In vitro studies have also demonstrated potential for intracellular colonization of osteocytes, osteoblasts, and osteoclasts. S. aureus has evolved a multitude of virulence mechanisms to achieve life-long infection of the bone, most notably colonization of OLCN. Targeting S. aureus proteins involved in these pathways could provide new targets for antibiotics and immunotherapies.

Kingella kingae and Osteoarticular Infections

OBJECTIVES

In this study, we aimed to contrast the bacteriologic epidemiology of osteoarticular infections (OAIs) between 2 patient groups in successive 10-year periods, before and after the extensive use of nucleic acid amplification assays in the diagnostic process.

METHODS

Epidemiologic data and bacteriologic etiologies of all children presenting with OAIs on admission to our institution over 20 years (1997-2016) were assessed retrospectively. The population was divided into 2 cohorts, using the standardized use of polymerase chain reaction as the cutoff point (2007). The conventional cohort included children with OAIs mainly investigated by using classic cultures, whereas the molecular cohort referred to patients also investigated by using molecular assays.

RESULTS

Kingella kingae was the most frequently isolated pathogen, responsible for 51% of OAIs, whereas other classic pathogens were responsible for 39.7% of cases in the molecular cohort. A statistically significant increase in the mean incidence of OAIs was observed, as was a decrease in the mean age at diagnosis after 2007. After 2007, the pathogen remained unidentified in 21.6% of OAIs in our pediatric population.

CONCLUSIONS

Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between 6 and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriologic etiology of OAIs.

Experience With a Care Process Model in the Evaluation of Pediatric Musculoskeletal Infections in a Pediatric Emergency Department

OBJECTIVES

Care process models (CPMs) for certain conditions have improved clinical outcomes in children. This study describes the implementation and impact of a CPM for the evaluation of musculoskeletal infections in a pediatric emergency department (ED).

METHODS

A retrospective pre-post intervention study was performed to analyze the impact of a musculoskeletal infection CPM. Patients were identified retrospectively through electronic order history for imaging of an extremity or joint and recommended laboratory tests. Clinical outcomes evaluated included hospital length of stay (LOS), time to magnetic resonance imaging (MRI), time to administration of antibiotics, hospital admission rate, and 30-day readmission rate.

RESULTS

Musculoskeletal infection evaluations completed in the ED were reviewed from 1 year before implementation (n = 383) and 2 years after implementation (n = 1219) of the CPM. A significant improvement in the time to antibiotic administration for all patients (4.3 vs 3.7 hours, P < 0.05) and for patients with confirmed musculoskeletal infections (9.5 vs 4.9 hours, P < 0.05) was observed after the implementation of the CPM. The overall time to MRI (13.2 vs 10.3 hours, P = 0.29) and hospital LOS (4.7 vs 3.7 days, P = 0.11) were improved for all patients but were not statistically significant. The admission rate and 30-day readmission were similar before and after the implementation of the CPM.

CONCLUSIONS

The implementation of a musculoskeletal infection CPM has standardized the approach to the evaluation and diagnosis of musculoskeletal infections resulting in a significant decrease in the time to administer antibiotics and a downward trend in time to MRI and hospital LOS.

Can a Septic Hip Decision Rule Aid in the Evaluation of Suspected Pediatric Musculoskeletal Infections?

BACKGROUND

Musculoskeletal (MSK) infections can be difficult to diagnose in acute care settings. The utility of clinical decision tools for pediatric MSK infections in an emergency department has not been well studied.

OBJECTIVE

Our aim was to evaluate the performance of a septic hip clinical decision rule (CDR) in the evaluation of pediatric musculoskeletal infections.

METHODS

We performed a retrospective study of children evaluated for an MSK infection in our emergency department from 2014 to 2016. Data collection included demographics, discharge diagnoses, and clinical/laboratory predictors from the CDR. A χ² analysis and Wilcoxon rank-sum tests compared patients with and without MSK infections. Logistic regression analysis examined the predictors for MSK infections. A receiver operating characteristic (ROC) curve was calculated to evaluate the performance of the predictors.

RESULTS

Of 996 evaluations included in the final analysis, 109 (10.9%) had MSK infections. In a multivariable model, an adjusted odds ratio (OR) was significant for fever (OR 3.9, 95% confidence interval [CI] 2.4-6.4), refusal to bear weight/pseudoparalysis (OR 4.4, 95% CI 2.7-7.1), and C-reactive protein (CRP) > 2.0 mg/dL (OR 5.4, 95% CI 3.2-9.1). The probability of infection was 75.1% with five predictors present, 1.9% for zero predictors, and 5.1% if one predictor was present. An ROC curve showed an area under the curve of 0.82, indicating moderate accuracy.

CONCLUSIONS

A septic hip CDR demonstrates a low predicted probability of an MSK infection with zero or one clinical predictor present and moderate predictability with all five predictors. Fever, refusal to bear weight/pseudoparalysis, and CRP > 2.0 mg/dL performed best and should alert providers to consider other MSK infections in addition to septic arthritis.

Validation of a novel molecular diagnostic panel for pediatric musculoskeletal infections: Integration of the Cepheid Xpert MRSA/SA SSTI and laboratory-developed real-time PCR assays for clindamycin resistance genes and Kingella kingae detection

BACKGROUND

Pathogen detection in pediatric patients with musculoskeletal infections relies on conventional bacterial culture, which is slow and can delay antimicrobial optimization. The ability to rapidly identify causative agents and antimicrobial resistance genes in these infections may improve clinical care.

METHODS

Convenience specimens from bone and joint samples submitted for culture to Children's Hospital Colorado (CHCO) from June 2012 to October 2016 were evaluated using a "Musculoskeletal Diagnostic Panel" (MDP) consisting of the Xpert MRSA/SA SSTI real-time PCR (qPCR, Cepheid) and laboratory-developed qPCRs for Kingella kingae detection and erm genes A, B, and C which confer clindamycin resistance. Results from the MDP were compared to culture and antimicrobial susceptibility testing (AST) results.

RESULTS

A total of 184 source specimens from 125 patients were tested. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the Xpert MRSA/SA SSTI compared to culture and AST results were 85%, 98%, 93%, and 95% respectively for MSSA and 82%, 100%, 100%, and 99% for MRSA. Compared to phenotypic clindamycin resistance in S. aureus isolates, the erm A, B, and C gene PCRs collectively demonstrated a sensitivity, specificity, PPV, and NPV of 80%, 96%, 67%, and 98%. In comparison to clinical truth, Kingella PCR had a sensitivity, specificity, PPV, and NPV of 100%, 99.5%, 100%, and 100%.

CONCLUSIONS

This novel MDP offers a rapid, sensitive, and specific option for pathogen detection in pediatric patients with musculoskeletal infections.

Comparison of Methicillin-resistant Versus Susceptible Staphylococcus aureus Pediatric Osteomyelitis

BACKGROUND

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) pediatric osteomyelitis has risen and been associated with a more severe clinical course than methicillin-susceptible Staphylococcus aureus (MSSA) infections. National databases have been underutilized to describe these trends. We compared demographics, clinical course, and outcomes for patients with MRSA versus MSSA osteomyelitis.

METHODS

We queried the 2009 and 2012 Healthcare Cost and Utilization Project Kids Inpatient Database for discharge records with diagnosis codes for osteomyelitis and S. aureus. We explored demographics predicting MRSA and evaluated MRSA versus MSSA as predictors of clinical outcomes including surgery, sepsis, thrombophlebitis, length of stay, and total charges.

RESULTS

A total of 4214 discharge records were included. Of those, 2602 (61.7%) had MSSA and 1612 (38.3%) had MRSA infections. Patients at Southern and Midwestern hospitals were more likely to have MRSA than those at Northeastern hospitals. Medicaid patients' odds of MRSA were higher than those with private insurance, and black patients were more likely to have MRSA compared with white patients. MRSA patients were more likely to undergo multiple surgeries compared with MSSA patients and were more likely to have complications including severe sepsis, thrombophlebitis, and pulmonary embolism. Patients with MRSA had longer lengths of stay than those with MSSA and higher total charges after controlling for length of stay.

CONCLUSION

Review of a national database demonstrates MRSA is more prevalent in the South and Midwest regions and among black patients. MRSA patients have more surgeries, complications, and longer lengths of stay.

LEVEL OF EVIDENCE

Level III.

OPAT: proof of concept in a peripheral Belgian hospital after review of the literature

Since its introduction in the 1970s in the United States, outpatient parenteral antibiotic/antimicrobial therapy (OPAT) has been adopted internationally for long-term intravenous (IV) treatment of stable infectious diseases. The aim is to provide a safe and successful completion of IV antimicrobial treatment at the ambulatory care center or at home without complications and costs associated with hospitalization. OPAT implementation has been accelerated by progress in vascular access devices, newly available antibiotics, the emphasis on cost-savings, as well as an improved patient comfort and a reduced incidence of health care associated infections with a similar outcome. OPAT utilization is supported by an extensive published experience and guidelines of the British Society of Antimicrobial Chemotherapy and the Infectious Diseases Society of America for adults as well as for children. Despite these recommendations and its widespread adoption, in Belgium OPAT is only fully reimbursed and established for cystic fibrosis patients. Possible explanations for this unpopularity include physician unfamiliarity and a lack of uniform funding arrangements with higher costs for the patient. This article aims to briefly review benefits, risks, indications, financial impact for supporting OPAT in a non-university hospital as standard of care. Our experience with OPAT at the ambulatory care center of our hospital and its subsequent recent introduction in the home setting is discussed.

Innate Immunity to Staphylococcus aureus: Evolving Paradigms in Soft Tissue and Invasive Infections

Staphylococcus aureus causes a wide range of diseases that together embody a significant public health burden. Aided by metabolic flexibility and a large virulence repertoire, S. aureus has the remarkable ability to hematogenously disseminate and infect various tissues, including skin, lung, heart, and bone, among others. The hallmark lesions of invasive staphylococcal infections, abscesses, simultaneously denote the powerful innate immune responses to tissue invasion as well as the ability of staphylococci to persist within these lesions. In this article, we review the innate immune responses to S. aureus during infection of skin and bone, which serve as paradigms for soft tissue and bone disease, respectively.

Treatment of subperiosteal abscesses in children: is drainage of the intramedullary canal required?

Acute osteomyelitis can be successfully treated with antibiotics alone. Surgery is utilized after failure of antibiotic treatment or if an abscess is present. Limited evidence exists with regard to whether intramedullary drainage is required in addition to the drainage of the subperiosteal abscess. We reviewed our 9-year experience of treating subperiosteal abscesses identifying 68 patients. Thirty patients underwent both intramedullary and abscess drainage, whereas 38 patients underwent drainage of the abscess alone at the initial procedure. Our analysis demonstrated a statistical significance (P=0.012) and odds ratio of 6.46 in favor of an intramedullary drainage to decrease risk for need for repeat surgical treatment.

Clinical Care Guideline for Improving Pediatric Acute Musculoskeletal Infection Outcomes

BACKGROUND

Acute pediatric musculoskeletal infections are common, leading to significant use of resources and antimicrobial exposure. In order to decrease variability and improve the quality of care, Children's Hospital Colorado implemented a clinical care guideline (CCG) for these infections. The purpose of this study is to evaluate clinical and resource outcomes PRE and POST this CCG.

METHODS

Retrospective chart review evaluated patients admitted to a large pediatric quaternary referral center (CHCO) diagnosed with acute osteomyelitis, septic arthritis, pyomyositis, and/or musculoskeletal abscess prior to and after guideline implementation. Primary outcomes included length of stay and overall antibiotic use, with additional secondary clinical, process, and therapeutic outcomes examined.

RESULTS

82 patients were identified in both the pre-CCG and post-CCG cohorts. There was a reduction in the median of all primary outcomes, including length of stay (0.6 median days decrease, P = .04), length of IV antibiotic therapy (4.9 median days decrease, P < .0001), and days of IV antibiotic therapy (6.4 median days decrease, P = .0004). Our median length of stay post-CCG was 4.9 days, the shortest reported length of stay for pediatric acute musculoskeletal infections to date. Additionally, there was a 24.5 hour reduction in median length of fever (P = .02), faster CRP normalization (P < .0001), 50% decrease in the number of related readmissions (P = .02), 34% decrease in central venous catheters placed (P < .0001), decreased time to first culture (P = .02), and 79% pathogen identification post-CCG (P = .056).

CONCLUSIONS

Implementation of a CCG for acute musculoskeletal infections improves patient, process and resource outcomes.

Community-acquired Methicillin-resistant Staphylococcus aureus Musculoskeletal Infections: Emerging Trends Over the Past Decade

BACKGROUND

The emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has altered the management of pediatric musculoskeletal infections. Yet, institution-to-institution differences in MRSA virulence may exist, suggesting a need to carefully examine local epidemiological characteristics. The purpose of this study was to compare MRSA and methicillin-sensitive S. aureus (MSSA) musculoskeletal infections with respect to prevalence and complexity of clinical care over the past decade at a single children's hospital.

METHODS

We retrospectively reviewed a series of patients presenting to The Children's Hospital of Philadelphia with a diagnosis of osteomyelitis, septic arthritis, or both over a 10-year period. Inclusion criteria were S. aureus (SA) infections proven by positive culture of blood, bone, or joint aspirate. Exclusion criteria were non-SA infectious etiologies. Hospital-acquired infections were also not included to exclusively evaluate acute, community-acquired cases. Data related to hospital course, laboratory values, and number of surgical interventions were collected and compared between MRSA and MSSA cohorts.

RESULTS

In our series of pediatric patients, we identified 148 cases of acute, community-acquired musculoskeletal SA infections (MRSA, n=37 and MSSA, n=111). The prevalence of MRSA musculoskeletal infections increased from 11.8% in 2001 to 2002 to 34.8% in 2009 to 2010. Compared with MSSA, MRSA infections resulted in higher presenting C-reactive protein levels (10.4 vs. 7.8 mg/L, P=0.04), longer inpatient stays (10 vs. 5 d, P<0.01), multiple surgical procedures (n>1) (38% vs. 14%, P<0.01), increased sequelae (27% vs. 6%, P<0.01), and more frequent admissions to the intensive care unit (16% vs. 3%, P<0.01).

CONCLUSIONS

At our institution over the past decade, we found an approximate 3-fold rise in community-acquired pediatric MRSA musculoskeletal infections accompanied by an elevated risk for complications during inpatient management. Awareness of the epidemiological trends of MRSA within the local community may guide parental counseling and facilitate timely and accurate clinical diagnosis and treatment.

LEVEL OF EVIDENCE

Level II-prognostic retrospective study.

Indicative Knee Posture in Children with Osteomyelitis of the Proximal Part of the Tibia with or without an Associated Subperiosteal Abscess: A Report of 3 Cases

CASE

Three patients with documented osteomyelitis of the proximal part of the tibia are described. On examination, all of the patients had an indicative finding of knee flexion to 90°. Because of the concern for septic arthritis, each patient underwent knee aspiration as part of the evaluation.All recovered with conventional infection treatment protocols.

CONCLUSION

High knee flexion beyond what is typical in patients with septic arthritis may indicate osteomyelitis of the proximal part of the tibia. Consideration of this diagnosis may lead to more expedient and efficient care.

Update in Pediatric Musculoskeletal Infections: When It Is, When It Isn't, and What to Do

Musculoskeletal infections, including osteomyelitis, septic arthritis, and pyomyositis, are a substantial cause of morbidity in children and adolescents. The increased virulence of infectious agents and the increased prevalence of antimicrobial-resistant pathogens, particularly methicillin-resistant Staphylococcus aureus, have resulted in a more complicated clinical course for diagnosis and management, which is evidenced by an increased length of hospital stays, incidence of complications, and number of surgical interventions. Musculoskeletal infections are a challenge for surgeons because they vary substantially in their presentation and in their required treatment, which is based on the causative organism, the location of the infection, and the age of the patient. The necessity for a prompt diagnosis is complicated by several diseases that may mimic musculoskeletal infection, including transient synovitis, autoimmune arthritis, and tumors. Recent innovations in diagnosis and management have provided surgeons with new options to differentiate musculoskeletal infections from these rapidly evolving disease pathologies. As diagnostic and treatment modalities improve, collaboration among surgeons from multiple disciplines is required to develop evidence-based clinical practice guidelines that minimize the effect of musculoskeletal infection and optimize clinical outcomes for patients.

Repurposing the Nonsteroidal Anti-inflammatory Drug Diflunisal as an Osteoprotective, Antivirulence Therapy for Staphylococcus aureus Osteomyelitis

Staphylococcus aureus osteomyelitis is a common and debilitating invasive infection of bone. Treatment of osteomyelitis is confounded by widespread antimicrobial resistance and the propensity of bacteria to trigger pathological changes in bone remodeling that limit antimicrobial penetration to the infectious focus. Adjunctive therapies that limit pathogen-induced bone destruction could therefore limit morbidity and enhance traditional antimicrobial therapies. In this study, we evaluate the efficacy of the U.S. Food and Drug Administration-approved, nonsteroidal anti-inflammatory (NSAID) compound diflunisal in limiting S. aureus cytotoxicity toward skeletal cells and in preventing bone destruction during staphylococcal osteomyelitis. Diflunisal is known to inhibit S. aureus virulence factor production by the accessory gene regulator (agr) locus, and we have previously demonstrated that the Agr system plays a substantial role in pathological bone remodeling during staphylococcal osteomyelitis. Consistent with these observations, we find that diflunisal potently inhibits osteoblast cytotoxicity caused by S. aureus secreted toxins independently of effects on bacterial growth. Compared to commonly used NSAIDs, diflunisal is uniquely potent in the inhibition of skeletal cell death in vitro Moreover, local delivery of diflunisal by means of a drug-eluting, bioresorbable foam significantly limits bone destruction during S. aureus osteomyelitis in vivo Collectively, these data demonstrate that diflunisal potently inhibits skeletal cell death and bone destruction associated with S. aureus infection and may therefore be a useful adjunctive therapy for osteomyelitis.

Acute Hematogenous Osteomyelitis in Children

This article discusses the most common organisms associated with acute hematogenous osteomyelitis in children. Magnetic resonance imaging is extremely important in evaluating the extent of the disease process. Osteomyelitis due to methicillin-resistant Staphylococcus aureus can be extremely difficult to treat and eradicate. It spreads quickly and causes local tissue necrosis. It is also associated with other serious sequelae such as deep venous thrombosis and septic pulmonary emboli. A multidisciplinary approach is needed to treat these infections. Hospital stays are often lengthy, complications are frequent, and patients are often critically ill. [Pediatr Ann. 2016;45(6):e204-e208.].

The limping child

Limping is a symptom of varied diagnoses in children and adolescents and can present a difficult diagnostic challenge for primary care clinicians. A careful and systematic evaluation can shorten the long list of potential diagnoses to direct appropriate diagnostic tests to determine the cause of the problem. Trauma and infections are the most common causes of limping. Inflammatory conditions, developmental diagnoses,and overuse injuries are other causes. Although rare, malignancies such as osteosarcoma and blood cell cancers must also be considered as potential causes of limping in children and adolescents.• Limping presents a diagnostic challenge due to the number of possible causes.• On the basis of consensus, diagnostic laboratory tests that include complete blood count, erythrocyte sedimentation rate,C-reactive protein, and blood cultures should be ordered if suspicion is high for infectious etiology.• On the basis of consensus, orthopedic emergencies are vascular compromise, compartment syndrome, and open fractures.• On the basis of moderate evidence and consensus, compartment syndrome in children presents with the three "As" analgesia,anxiety, and agitation. (4)• On the basis of strong evidence and consensus, septic arthritis asa diagnosis increases with the number of Kocher criteria present(temperature >38.5°C, white blood cell count >12,000/mL[12109/L], erythrocyte sedimentation rate >40 mm/h, and inability to bear weight). (8)• On the basis of moderate evidence and consensus, laboratory studies are not always definitive for diagnosis of juvenile idiopathic arthritis. (13)• On the basis of consensus, it is always important to examine the joint above and the joint below the area of the chief compliant,specifically when looking at slipped capital femoral epiphysis and Legg-Calvé-Perthes disease.

Clinical and laboratory parameters associated with multiple surgeries in children with acute hematogenous osteomyelitis

BACKGROUND

In the era of methicillin-resistant Staphylococcus aureus, surgical intervention seems to be increasingly common as an adjunct to treatment for pediatric acute hematogenous osteomyelitis (AHO). The purpose of this study is to identify objective clinical and laboratory parameters that are associated with repeated surgical intervention during the acute phase of treatment.

METHODS

Fifty-seven children who were consecutively evaluated and treated for AHO at a single institution during 2009 were studied retrospectively. Objective clinical and laboratory parameters related to length of hospitalization were recorded for each child. Univariate analysis was performed with ordinal logistic regression, χ, Fisher exact, and Wilcoxon rank-sum and 2-value tests to identify independent variables associated with the occurrence of surgery in children with AHO. Multivariate logistic regression was used to identify parameters associated with repeated surgical intervention.

RESULTS

Sixteen children were treated with antibiotics alone and no surgery. There were 41 children who had at least 1 surgery and 12 who underwent ≥2 surgeries. Multiple logistic regression showed that a swollen extremity (P=0.002), initial C-reactive protein (CRP) value >9.9 mg/dL (P=0.02), and respiration rate >27 breaths/min (P=0.02) were significantly associated with the occurrence of at least 1 surgery. The best model to identify the occurrence of repeated surgical intervention in children with AHO included: ≥4 febrile days on antibiotics; and the CRP values at admission (>19.8 mg/dL), 48 hours after the initial surgery (>21.5 mg/dL), and 96 hours after the initial surgery (>15.3 mg/dL).

CONCLUSIONS

Children with AHO who have sustained marked elevation of CRP values during the first 96 hours after surgery and who remain febrile while on antibiotics have an increased likelihood of repeated surgical intervention and should be evaluated carefully for additional surgical treatment.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Methicillin-resistant staphylococcus aureus bone and joint infections in children

Methicillin-resistant Staphylococcus aureus has been a clinically significant pathogen in orthopaedics for more than a decade. Research shows that these infections are more virulent and that treatment requires greater use of hospital resources. A multidisciplinary approach involving emergency department physicians, radiologists, interventional radiologists, MRI technicians, pediatricians, infectious disease specialists, anesthesiologists, and orthopaedic surgeons is necessary to optimize outcomes and minimize costs. Early use of MRI helps delineate the extent of infection, aids in the consideration of surgery, and provides valuable information for surgical planning. Healthcare providers need to stay vigilant during the course of the disease to detect other sites of infection or complications of methicillin-resistant S aureus, such as deep vein thrombosis and septic pulmonary emboli. Patients with infections near growth centers require long-term monitoring to ensure the absence of growth disturbances. Physicians should help educate patients and families on prevention strategies and be aware of guidelines for students to return to school and athletes to return to play.

Good practice recommendations for paediatric outpatient parenteral antibiotic therapy (p-OPAT) in the UK: a consensus statement

There is compelling evidence to support the rationale for managing children on intravenous antimicrobial therapy at home whenever possible, including parent and patient satisfaction, psychological well-being, return to school/employment, reductions in healthcare-associated infection and cost savings. As a joint collaboration between the BSAC and the British Paediatric Allergy, Immunity and Infection Group, we have developed good practice recommendations to highlight good clinical practice and governance within paediatric outpatient parenteral antibiotic therapy (p-OPAT) services across the UK. These guidelines provide a practical approach for safely delivering a p-OPAT service in both secondary care and tertiary care settings, in terms of the roles and responsibilities of members of the p-OPAT team, the structure required to deliver the service, identifying patients and pathologies that are suitable for p-OPAT, ensuring appropriate vascular access, antimicrobial choice and delivery and the clinical governance aspects of delivering a p-OPAT service. The process of writing a business case to support the introduction of a p-OPAT service is also addressed.

Independent analysis of a clinical predictive algorithm to identify methicillin-resistant Staphylococcus aureus osteomyelitis in children

BACKGROUND

The number of serious, life-threatening musculoskeletal infections in children due to methicillin-resistant Staphylococcus aureus (MRSA) infections is increasing. The early identification of the bacteria causing osteomyelitis is critical to determine the appropriate antibiotic treatment. A recent study proposed a clinical algorithm to predict which infections were caused by MRSA by stratifying basic clinical values at the time of admission for children with osteomyelitis. The purpose of this study is to apply that predictive algorithm on an independent patient population to determine its wider applicability.

METHODS

This was a retrospective chart review at a tertiary care children's hospital. All children who were treated for a culture-positive osteomyelitis were identified over a 3-year period. The previously reported predictors, determined by multivariate regression analysis, of MRSA infection (temperature >38°C, hematocrit <34%, white blood cell count >12,000/µL, and C-reactive protein >13 mg/L) were determined for each patient. The number of positive predictors was then correlated with the percentage of cases that were MRSA positive.

RESULTS

A total of 58 patients with culture-positive osteomyelitis were identified from 2008 to 2010. Sixteen of the infections were caused by MRSA (overall 26%). The percentage of patients with MRSA osteomyelitis according to the number of risk factors were as follows: all 4 risk factors, 50% (1 out of 2 patients); 3 risk factors, 42% (5 out of 12 patients); 2 risk factors, 21% (4 out of 19 patients); 1 risk factor, 50% (6 out of 12 patients); and 0 risk factor, 0% (0 out of 13 patients).

CONCLUSIONS

The previously reported clinical predictive algorithm had a relatively poor diagnostic performance in this independent patient population. Specifically, the percentages of MRSA were the same for 1 risk factor compared with 4 (50%). Differences in bacteria strain, host responses, and a variety of other confounding variables could be responsible for these differences. Specific genetic markers may be the best early test to identify MRSA infections in the future.

LEVEL OF EVIDENCE

Level III-case-control series.

The impact of evidence-based clinical practice guidelines applied by a multidisciplinary team for the care of children with osteomyelitis

BACKGROUND

Care of children with osteomyelitis requires multidisciplinary collaboration. This study evaluates the impact of evidence-based guidelines for the treatment of pediatric osteomyelitis when utilized by a multidisciplinary team.

METHODS

Guidelines for pediatric osteomyelitis were developed and were implemented by a multidisciplinary team comprised of individuals from several hospital services, including orthopaedics, pediatrics, infectious disease, nursing, and social work, who met daily to conduct rounds and make treatment decisions. With use of retrospective review and statistical analysis, we compared children with osteomyelitis who had been managed at our institution from 2002 to 2004 (prior to the implementation of the guidelines), referred to as Group I in this study, with those who were managed in 2009 according to the guidelines, referred to as Group II.

RESULTS

Two hundred and ten children in Group I were compared with sixty-one children in Group II. No significant differences between the two cohorts were noted for age, sex, incidence of methicillin-resistant Staphylococcus aureus infection (18.1% in Group I compared with 26.2% in Group II), incidence of methicillin-sensitive Staphylococcus aureus infection (23.8% in Group I compared with 27.9% in Group II), bacteremia, or surgical procedures. Significant differences (p < 0.05) between cohorts were noted for each of the following: the delay in magnetic resonance imaging after admission (2.5 days in Group I compared with one day in Group II), the percentage of patients who had received clindamycin as the initial antibiotic (12.9% in Group I compared with 85.2% in Group II), the percentage of patients who had had a blood culture before antibiotic administration (79.5% in Group I compared with 91.8% in Group II), the percentage of patients who had had a culture of tissue from the infection site (62.9% in Group I compared with 78.7% in Group II), the percentage of patients in whom the infecting organism was identified on tissue or blood culture (60.0% in Group I compared with 73.8% in Group II), the number of antibiotic changes (2.0 changes in Group I compared with 1.4 changes in Group II), and the mean duration of oral antibiotic use (27.7 days in Group I compared with 43.7 days in Group II). When compared with Group I, Group II had clinically important trends of a shorter total length of hospital stay (12.8 days in Group I compared with 9.7 days in Group II; p = 0.054) and a lower hospital readmission rate (11.4% in Group I compared with 6.6% in Group II; p = 0.34).

CONCLUSIONS

Evidence-based treatment guidelines applied by a multidisciplinary team resulted in a more efficient diagnostic workup, a higher rate of identifying the causative organism, and improved adherence to initial antibiotic recommendations with fewer antibiotic changes during treatment. Additionally, there were trends toward lower hospital readmission rates and a shorter length of hospitalization.

Osteomyelitis and septic arthritis in children: current concepts

PURPOSE OF REVIEW

The cause, epidemiology, diagnosis, and treatment of osteoarticular infections have changed considerably in recent years. The current review includes the most up to date literature on pediatric septic arthritis and osteomyelitis.

RECENT FINDINGS

There is controversy over whether osteoarticular infection rates are increasing or decreasing. Changes in epidemiology may be related to improved methods of diagnosis. The pathogens responsible for osteoarticular infections in children have changed with alterations in immunization practices, emergence of resistant bacteria, and changes in patterns of immune modulating diseases and medications in children. Special culture techniques and PCR may help to identify pathogens that are difficult to culture. Surgical debridement is typically required for joint infections and chronic osteomyelitis, whereas acute osteomyelitis can typically be treated with medication alone. Needle aspiration/irrigation alone has been described as an alternative to surgical incision/drainage for septic arthritis, but this practice has not been widely adopted. Intravenous antibiotic therapy for 2-4 days followed by 20 days of oral therapy is effective for treating uncomplicated cases of osteomyelitis, whereas 2-4 days of intravenous antibiotics followed by 10 days of oral therapy is sufficient for septic arthritis. Steroids have shown some improved short-term clinical outcomes in patients with septic arthritis.

SUMMARY

Up to date knowledge of emerging pathogens, utilization of modern diagnostic techniques and implementation of new shorter treatment regimens can optimize the treatment of pediatric septic arthritis and osteomyelitis.

[Staphylococcus aureus infections in the intensive care unit: clinical and epidemiological characteristics]

INTRODUCTION

There has been an increase in invasive Staphylococcus Aureus infections over the last few years, which have required admission to the pediatric intensive care unit (PICU).

PATIENTS AND METHODS

All patients with S. aureus infection who were admitted to PICU were enrolled in a retrospective study (January 2006-June 2010). The patients were classified into 2 groups: community-acquired infection (Group 1) and nosocomial infection (Group 2). We recorded epidemiological data, type of S. aureus (methicillin-susceptible S. aureus [MSSA], methicillin-resistant S. aureus [MRSA]), risk factors, site of infection, presence of hemodynamic instability, respiratory support, and mortality.

RESULTS

A total of 51 patients were enrolled, 21 belonging to Group 1 and 30 to Group 2. The median age was lower in Group 1 (1.6 years vs 3.2 years; P=.009). MSSA was isolated in 88% of cases. MRSA was detected in 6/51 (12%) of cases, which were isolated in the later study period (January 2009-June 2010). The risk factors for infection were: immunosuppression, venous catheter, institutionalization, mechanical ventilation, previous surgery, previous trauma and chronic osteomyelitis. A large majority (83%) of the patients with MRSA infection had risk factors. The type of infection was varied, with respiratory tract infection being the most common (75%). Hemodynamic instability was observed in 43% of patients. Most patients (86%) required respiratory support. One patient in Group 1 died of necrotizing pneumonia caused by MSSA.

CONCLUSIONS

Infections by S. aureus in children are severe and have a high morbidity. Respiratory infection was the most common in our series. Isolation of MSSA is common in these infections, although, an increase in the number of infections by MRSA was observed during the latter part of the study.

Pathologic fractures in children with acute Staphylococcus aureus osteomyelitis

BACKGROUND

Osteomyelitis is a common pediatric musculoskeletal infection. This infection can weaken the normal bone structure, resulting in the risk of a pathologic fracture. The purpose of this study was to evaluate the risk factors for pathologic fracture in children with Staphylococcus aureus osteomyelitis.

METHODS

Seventeen children who were treated for a pathologic long-bone fracture secondary to Staphylococcus aureus osteomyelitis between January 2001 and January 2009 at a tertiary-care pediatric hospital were identified. These patients were compared with a control group consisting of forty-nine children with Staphylococcus aureus osteomyelitis without a fracture who were matched for age, sex, and methicillin susceptibility. A retrospective review of the clinical records, magnetic resonance imaging (MRI) studies, and microbiologic findings was performed.

RESULTS

Patients who developed a fracture presented with osteomyelitis at a mean age of 8.8 years (range, two to seventeen years). Fifteen of the seventeen patients had methicillin-resistant Staphylococcus aureus (MRSA) isolates, and two had methicillin-susceptible Staphylococcus aureus (MSSA). The mean time from disease onset to fracture was 72.1 days (range, twenty to 150 days). The duration of hospitalization, number of surgical procedures, duration of antibiotic treatment, and total number of complications differed significantly between the two groups. MRI studies at the time of admission demonstrated a significantly greater prevalence of subperiosteal abscess and greater circumferential size of such an abscess in the patients with a fracture. A sharp zone of abnormally diminished enhancement of the marrow was also more common in these patients. The USA300-0114 pulsotype was more commonly associated with an elevated likelihood of fracture.

CONCLUSIONS

Staphylococcus aureus osteomyelitis is a serious infection that may predispose children to pathologic fractures. Protected weight-bearing and activity restriction are recommended in children with Staphylococcus aureus osteomyelitis who have the risk factors demonstrated in this study.

Approach to a child with monoarthritis

Arthritis in childhood is common. The pattern, presentation and duration of arthritis help differentiate between the various possible diagnoses. When only one joint is involved, i.e., monoarthritis, it may be difficult to make a diagnosis as there are many possibilities both acute and chronic in nature. A detailed history and clinical examination is important to reach a correct diagnosis and the single most important investigation when a child presents acutely is a joint aspiration to rule out septic arthritis that may destroy the joint in hours. Inflammatory markers, antinuclear antibody testing, test for tuberculosis and imaging (in specific cases) play an important role in the diagnosis of a child that presents with a chronic monoarthritis. In this article we provide a clinical approach to the diagnosis of monoarthritis in a child.