Bone and joint infections

Diagnosis and Management of Acute Osteoarticular Infections: Summary of New Guidelines

Acute hematogenous osteomyelitis (AHO) and acute bacterial arthritis (ABA) are among the most common invasive bacterial infections in otherwise healthy children. The diagnosis of AHO and ABA requires a high index of suspicion in children presenting with fever and musculoskeletal pain and judiciously chosen laboratory and imaging studies. Choosing the appropriate empirical antibiotic requires familiarity with local susceptibility patterns, especially for Staphylococcus aureus. Typical antibiotic duration for osteoarticular infection is 2-4 weeks depending on the type of infection, response to therapy, and presence of complications. Transitioning from parenteral to oral antibiotics is guided by clinical and laboratory evidence of resolving infection. This review will provide an overview of the recommendations contained in the 2 recently published guidelines for the management of AHO and ABA.

Comprehensive Analysis of the Spectrum of Osteoarticular Infections in Children

BACKGROUND

Studies of pediatric osteoarticular infections (OAIs) mostly focus on acute hematogenous osteomyelitis (AHO) and acute bacterial arthritis (ABA). A comprehensive descriptive analysis of pediatric OAIs, including subacute, chronic, and non-hematogenous types, is lacking.

METHODS

A detailed analysis of all pediatric OAIs was undertaken at 2 academic centers, Hasbro Children's Hospital, Providence, RI, and Nationwide Children's Hospital, Columbus, OH. Infections were classified as AHO (with or without suppurative arthritis), isolated ABA, subacute or chronic hematogenous osteomyelitis (SCHO), non-hematogenous osteoarticular infection (NHI), or hardware-associated osteoarticular infection (HOI). Clinical, radiological, and laboratory characteristics were compared.

RESULTS

A total of 582 consecutive cases of OAIs were included: 295 AHO (51%), 88 ABA (15%), 76 NHI (13%), 73 HOI (13%), and 50 SCHO (9%). Median age was significantly higher for HOI (14.5 years), NHI (11.8), and SCHO (10.4) than for AHO (9) and ABA (5) (P < .001). Patients with AHO or ABA were more likely (P < .001) to be febrile (each 84%) compared with other groups (45%-56%) and had higher biomarkers of inflammation (white blood cell, erythrocyte sedimentation rate, C-reactive protein). A causative organism was identified in 74% of cases, mostly from tissue specimens (78%). Staphylococcus aureus was the most common organism across infection types (34%-55% of cases), while polymicrobial infection was common in NHI (22%) and HOI (21%). Chronic morbidity complicated infections in 89 (15%) patients, the majority of whom (66%) had SCHO, NHI, or HOI.

CONCLUSIONS

SCHO, NHI, and HOI accounted for a significant proportion of pediatric OAIs and contributed disproportionately to chronic morbidity.

Early Bone Ischemia in Pediatric Acute Hematogenous Osteomyelitis and its Association With Progression to Chronic Osteomyelitis: New Insights From Gadolinium-enhanced Subtraction MRI

BACKGROUND

Acute hematogenous osteomyelitis (AHO), the most common osteoarticular infection in children, carries a significant risk for chronic complications. Predicting chronic complications early in the course of disease is challenging. The underlying pathogenesis of complications is not fully understood.

METHODS

Children who presented to Sultan Qaboos University Hospital, Muscat, Oman between January 2015 and April 2022 for AHO were identified by a search of magnetic resonance imaging (MRI) records. Children between 1 month and 18 years of age who did not meet exclusion criteria, and whose MRI also included gadolinium-enhanced subtraction (GES) sequences were included in the analysis. Outcomes were compared between patients who showed early evidence of bone ischemia and those who did not.

RESULTS

The analysis included 11 children who had GES MRI sequences from among 18 AHO cases in total. Median age was 5 years (IQR, 4-9), and 82% were males. Median duration of symptoms at presentation was 5 days (IQR, 3-7). GES sequences showed early bone ischemia in 6 of 11 (55%) patients. Patients with early bone ischemia were treated with significantly longer durations of IV antibiotics (median 23 vs. 10 days, P = 0.017) and oral antibiotics (median 134 vs. 29 days, P = 0.004), and required more surgical debridements (median 3 vs. 0 debridements, P = 0.017). Chronic osteomyelitis only developed among patients with early bone ischemia (5/6 vs. 0/5, P = 0.015).

CONCLUSIONS

In pediatric AHO, GES MRI sequences revealed early bone ischemia in a significant proportion of patients. Early bone ischemia was strongly associated with progression to chronic osteomyelitis.

Microbiological Spectrum of Osteoarticular Infections and Their Management in Mongolian Children

Introduction. Osteoarticular infections (OI) in children cause considerable morbidity with associated long-lasting sequelae. Comprehensive clinical and microbiological data in Mongolian children are missing. Objectives. To generate epidemiological, clinical and microbiological data on osteoarticular infections (OI) in Mongolian children after the introduction of a standardized management protocol. Methods. A prospective study was done between 2019 and 2022 at the only tertiary pediatric hospital in Mongolia. Results. Forty-two children presented with septic arthritis (SA), 6 with osteomyelitis (OM) and 23 with combined SA and OM. Newborns and young infants (≤3 months) comprised 38.%. A causative organism was identified in 38 children: Staphylococcus aureus (n = 31), Klebsiella spp (n = 3), Enterobacter spp (n = 2), Enterobacter spp + Klebsiella spp (n = 1) and Candida albicans (n = 1). Five children (7%) had sequelae. Mongolian children with OI were younger compared to other cohorts. Conclusion. A standardized protocol for the management of OI in children was taken up well by the patients and treating staff leading to improved pathogen detection, facilitating antimicrobial stewardship in the future.

Logistic regression analysis of multiple rapid admission hematological indicators to determine the risk of osteomyelitis in infected children

To analyze the differences of multiple rapid admission hematological indicators between children with acute osteomyelitis (AO) and children with other orthopedic infectious diseases and clarify the characteristics of admission inspection hematological indicators of children with AO. Retrospective analysis of this pilot study was proceeded on 144 children with limbs infectious diseases, who were treated in our hospital. According to their final diagnosis, they were divided into osteomyelitis group (n = 57) and non-osteomyelitis group (n = 87). Case data were collected, including sex, age, body temperature, white blood cell (WBC), C-reactive protein (CRP), etc. The differences in these indexes between the two groups of patients were compared, and then, the index with significant differences was selected for univariate and multivariate logistic regression analysis. There were significant differences between the two groups in age, body temperature, CRP, ESR, fibrinogen, total bilirubin, alanine aminotransferase, aspartate aminotransferase (AST), glutamyl transpeptidase, creatinine, PCT, albumin (ALB), and ALB globulin ratio (A/G) ( P  < 0.05). The results of univariate and multivariate logistic regression analysis showed that the age of ≥5 years (4.592, 1.711-12.324), WBC (>1.5 × 10 9 /L) (0.271, 0.102-0.718), ESR (>50 mm/h) (6.410, 2.291-17.936), PCT (>0.06 µg/L) (3.139, 1.066-9.243), and AST (>40 U/L) (11.174, 1.718-72.666) was an independent risk factor of AO in children with orthopedic infectious diseases ( P  < 0.05). For newly admitted children with orthopedic infectious diseases, if the age ≥ 5 years, WBC ≤ 1.5 × 10 9 /L, ESR > 50 mm/h, PCT > 0.06 µg/L, and AST > 40 U/L, the occurrence of AO should be alerted.

Osteoarticular Infections: Younger Children With Septic Arthritis and Low Inflammatory Patterns Have a Better Prognosis in a European Cohort

BACKGROUND

Osteoarticular infections (OAI) are associated with complications and sequelae in children, whose prediction are of great importance in improving outcomes. We aimed to design risk prediction models to identify early complications and sequelae in children with OAI.

METHODS

This observational study included children (>3 months-17 years old) with acute OAI admitted to a tertiary-care pediatric hospital between 2008 and 2018. Clinical treatment, complications and sequelae were recorded. We developed a multivariable logistic predictive model for an acute complicated course (ACC) and another for sequelae.

RESULTS

A total of 240 children were identified, 17.5% with ACC and 6.0% and 3.6% with sequelae at 6 and 12 months of follow-up, respectively. In the multivariable logistic predictive model for ACC, predictors were fever at admission [adjusted odds ratio (aOR): 2.98; 95% confidence interval (CI): 1.10-8.12], C-reactive protein ≥100 mg/L (aOR: 2.37; 95% CI: 1.05-5.35), osteomyelitis (aOR: 4.39; 95% CI: 2.04-9.46) and Staphylococcus aureus infection (aOR: 3.50; 95% CI: 1.39-8.77), with an area under the ROC curve of 0.831 (95% CI: 0.767-0.895). For sequelae at 6 months, predictors were age ≥4 years (aOR: 4.08; 95% CI: 1.00-16.53), C-reactive protein ≥110 mg/L (aOR: 4.59; 95% CI: 1.25-16.90), disseminated disease (aOR: 9.21; 95% CI: 1.82-46.73) and bone abscess (OR: 5.46; 95% CI: 1.23-24.21), with an area under the ROC curve of 0.887 (95% CI: 0.815-0.959).

CONCLUSIONS

In our model we could identify patients at low risk for complications and sequelae, probably requiring a less aggressive approach.

Appropriate Antibiotic Duration in Pediatric Bone and Joint Infection: A Systematic Review

Background: Optimal duration of antibiotic therapy for childhood bone and joint infection (BJI) remains controversial, despite recent literature in support of shorter courses and early oral switch. We have reviewed the literature to summarize current evidence for reduced duration of antibiotic therapy with particular attention to regional variation in pathogen type and treatment success. Methods: Systematic review was undertaken of studies examining acute pediatric bone and joint infection over the period January 1980-December 2022 for children aged up to 18 years. Cohort studies, systematic reviews, randomized controlled trials, and prospective studies were analyzed for data on treatment success rates and duration of therapy. Results: A total of 34 studies met inclusion criteria reporting treatment duration for 8337 cases of acute BJI. There were five prospective studies, 21 cohort studies, six randomized controlled trials, and three systematic reviews. The shortest duration of therapy tested prospectively was 10 days of combined IV and oral treatment. In the populations examined by this systematic review, there were no increased failure rates as a consequence of shorter therapy. Neonates and children with comorbid or complicated illness were routinely excluded from higher-level studies. Conclusions: There is moderate evidence for shortened duration of therapy with early switch to oral antibiotics in select patients. Studies reporting good success for reduced therapy included healthy patients with uncomplicated disease. Regional disease variation and study protocol heterogeneity limit widespread adoption of short-course treatment. Additionally, the experience of BJI is diverse. Although the majority of children respond well to treatment, there is a subset who demonstrate acute or chronically complicated disease. Further research is needed to define patient and disease factors that contribute to treatment failure. Level of Evidence: Systematic review Level III Key Concepts•In the populations examined in this systematic review, there was no evidence of increased failure rates as a consequence of shorter therapy.•It may be reasonable to recommend short course of IV therapy with early transition to oral medication in those >3 months of age without signs of complicated disease.•Clinicians need to be aware of regional disease variation and patient factors associated with treatment failure.•Pathogen and genetic variability likely contribute to the success of treatment in childhood BJI.

An Update on Pediatric Acute Hematogenous Osteomyelitis in New Zealand - A Decade on

INTRODUCTION

New Zealand (NZ) has high rates of pediatric acute hematogenous osteomyelitis (AHO) with males and children of Pasifika and Māori ethnicity overrepresented.

AIMS

To update the incidence of Pediatric AHO over 10 years, identifying trends in presentation, organisms, treatment, and outcomes.

METHODS

A 10-year retrospective review of children aged 6 weeks to 15 years admitted with Pediatric AHO across two centers from 2008 to 2017. Demographic data, features of presentation, investigations, management, and complications were collected. Incidence was calculated from census data. Data were compared with our osteomyelitis database from the previous decade. (1).

RESULTS

796 cases were identified. The incidence was 18 per 100,000 per annum. The average age was 7.7 years. Pasifika and Māori children are overrepresented (57%). 370 children (51%) came from low socioeconomic areas. Methicillin-sensitive Staphylococcus aureus was the most common pathogen (87%). Methicillin-resistant Staphylococcus aureus (MRSA) rates are low (4.4%). Forty-four (5.5%) children were admitted to the Pediatric Intensive Care Unit (PICU) with 9% mortality. The mean duration of antibiotics was 40 days. 325 children (41%) had surgery. Chronic infection has increased from 1.7% to 5.7%.

CONCLUSIONS

NZ has high rates of AHO, however, the incidence has decreased from the previous decade. Males, those in low socioeconomic areas, Pasifika and Māori have high disease burden. The use of MRI as a diagnostic modality has increased. Future studies should focus on improving treatment via prospective analysis and reporting long-term morbidity to improve outcomes for children with severe disease and reduce rates of chronic infection.

In vitro Activity of Ceftaroline Against an International Collection of Kingella kingae Isolates Recovered From Carriers and Invasive Infections

BACKGROUND

Improvements in blood culture techniques and molecular-based diagnostics have led to increased recognition of Kingella kingae as an invasive human pathogen causing bacteremia, septic arthritis, osteomyelitis and endocarditis in young children. Serious disease and potentially life-threatening complications of infection due to K. kingae necessitate timely identification and appropriate antimicrobial therapy. Ceftaroline is a fifth-generation broad spectrum cephalosporin that possesses activity against Gram-negative and Gram-positive pathogens similar to third-generation cephalosporins, but also includes methicillin-resistant Staphylococcus aureus . This study reports the in vitro activity of ceftaroline and comparator agents against an international collection of K. kingae isolates.

METHODS

A collection of 308 K. kingae isolates was obtained primarily from children with bacteremia, endocarditis, osteoarticular infections or from asymptomatic pediatric carriers. Isolates were tested for antibiotic susceptibility using Clinical and Laboratory Standard Institute broth microdilution methodology and screened for β-lactamase production using a nitrocefin chromogenic test.

RESULTS

Ceftaroline inhibited all K. kingae isolates at ≤0.06 mg/L (MIC 50/90 , 0.015/0.03 mg/L). Ceftaroline MICs were similar to results with ceftriaxone (MIC 50/90 , 0.015/0.015 mg/L), meropenem (MIC 50/90 , 0.015/0.015 mg/L) and ampicillin-sulbactam (MIC 50/90 , 0.06/0.06 mg/L). Ceftaroline MICs were slightly lower than MICs for cefuroxime and amoxicillin/clavulanate (MIC 50/90 , 0.06/0.12 mg/L). MICs were high for clindamycin (MIC 50/90 , 2/4 mg/L) and oxacillin (MIC 50/90 , 4/8 mg/L). Sixteen isolates (5.2%) yielded a positive nitrocefin test indicating production of β-lactamase; ceftaroline demonstrated equivalent MICs against β-lactamase - positive and β-lactamase - negative strains (MIC 50/90 , 0.015/0.3 mg/L).

CONCLUSIONS

The potent activity of ceftaroline against this large international collection of K. kingae isolates supports further clinical evaluation in children.

Pediatric Emergency MRI

There is an overall increase in the use of imaging in the pediatric emergency room setting, which is accompanied by a reduction in computed tomography examinations performed mainly due to the increased awareness of the risks of ionizing radiation. Advances in MRI technology have led to shortened scan time, decreased motion sensitivity, and improved spatial resolution. With increased access to MRI in the emergency room setting, the goal of this article is to review major applications of MR in pediatric emergency room patients.

Interactions of two enantiomers of a designer antimicrobial peptide with structural components of the bacterial cell envelope

Antimicrobial peptides (AMPs) have great potential in treating multi-drug resistant bacterial infections. The antimicrobial activity of d-enantiomers is significantly higher than l-enantiomers and sometimes selectively enhanced against Gram-positive bacteria. Unlike phospholipids in the bacterial plasma membrane, the role of other bacterial cell envelop components is often overlooked in the mode of action of AMPs. In this work, we explored the structural interactions between the main different structural components in Gram-negative/Gram-positive bacteria and the two enantiomers of a designer AMP, GL13K. We observed that both l-GL13K and d-GL13K formed self-assembled amyloid-like nanofibrils when the peptides interacted with lipopolysaccharide and lipoteichoic acid, components of the outer membrane of Gram-negative bacteria and cell wall of Gram-positive bacteria, respectively. Another cell wall component, peptidoglycan, showed strong interactions exclusively with d-GL13K and formed distinct laminar structures. This specific interaction between peptidoglycans and d-GL13K might contribute to the enhanced activity of d-GL13K against Gram-positive bacteria as they have a much thicker peptidoglycan layer than Gram-negative bacteria. A better understanding of the specific role of bacterial cell envelop components in the AMPs mechanism of action can guide the design of more effective Gram-selective AMPs.

Italian consensus on the therapeutic management of uncomplicated acute hematogenous osteomyelitis in children

BACKGROUND

Acute hematogenous osteomyelitis (AHOM) is an insidious infection of the bone that more frequently affects young males. The etiology, mainly bacterial, is often related to the patient's age, but it is frequently missed, owing to the low sensitivity of microbiological cultures. Thus, the evaluation of inflammatory biomarkers and imaging usually guide the diagnosis and follow-up of the infection. The antibiotic treatment of uncomplicated AHOM, on the other hand, heavily relies upon the clinician experience, given the current lack of national guidelines for the management of this infection.

METHODS

A systematic review of the studies on the empirical treatment of uncomplicated AHOM in children published in English or Italian between January 1, 2009, and March 31, 2020, indexed on Pubmed or Embase search engines, was carried out. All guidelines and studies reporting on non-bacterial or complicated or post-traumatic osteomyelitis affecting newborns or children older than 18 years or with comorbidities were excluded from the review. All other works were included in this study.

RESULTS

Out of 4576 articles, 53 were included in the study. Data on different topics was gathered and outlined: bone penetration of antibiotics; choice of intravenous antibiotic therapy according to the isolated or suspected pathogen; choice of oral antibiotic therapy; length of treatment and switch to oral therapy; surgical treatment.

CONCLUSIONS

The therapeutic management of osteomyelitis is still object of controversy. This study reports the first Italian consensus on the management of uncomplicated AHOM in children of pediatric osteomyelitis, based on expert opinions and a vast literature review.

The role of Kingella kingae in pre-school aged children with bone and joint infections

OBJECTIVES

The Pre-school Osteoarticular Infection (POI) study aimed to describe the burden of disease, epidemiology, microbiology and treatment of acute osteoarticular infections (OAI) and the role of Kingella kingae in these infections.

METHODS

Information about children 3-60 months of age who were hospitalized with an OAI to 11 different hospitals across Australia and New Zealand between January 2012 and December 2016 was collected retrospectively.

RESULTS

A total of 907 cases (73%) were included. Blood cultures grew a likely pathogen in only 18% (140/781). The peak age of presentation was 12 to 24 months (466/907, 51%) and Kingella kingae was the most frequently detected microorganism in this age group (60/466, 13%). In the majority of cases, no microorganism was detected (517/907, 57%). Addition of PCR to culture increased detection rates of K. kingae. However, PCR was performed infrequently (63/907, 7%).

CONCLUSIONS

This large multi-national study highlights the need for more widespread use of molecular diagnostic techniques for accurate microbiological diagnosis of OAI in pre-school aged children. The data from this study supports the hypothesis that a substantial proportion of pre-school aged children with OAI and no organism identified may in fact have undiagnosed K. kingae infection. Improved detection of Kingella cases is likely to reduce the average length of antimicrobial treatment.

Clinical features and outcomes in children with bone and joint infections of the ankle or foot

BACKGROUND

The foot and ankle are uncommon sites of bone and joint infections (BJIs) in children. The objectives of the present study were to determine the clinical and bacteriologic features of BJIs and to assess any associated complications and orthopedic sequelae.

METHODS

We performed a retrospective, single-center study of children treated for foot or ankle BJIs between 2008 and 2018 in a French university medical center. A total of 23 children were included. The median age at diagnosis was 9.1 years. Osteomyelitis was noted in 14 cases; it involved the calcaneus in seven cases, the distal fibula in four cases, the first metatarsal in two cases, and the distal tibia in one case. Arthritis affected the ankle in six cases and the cuneiform-cuboidal joint in one case. In two cases, osteoarthritis of the ankle was associated with distal osteomyelitis of the tibia. Clinical, radiological, and bacteriological parameters, surgical procedures, complications, and sequelae were recorded and analyzed.

RESULTS

The median (range) time to diagnosis was 3.18 days (0-10), and trauma was reported in four cases. Fever was present on admission in 18 cases, and the serum C-reactive protein level was elevated in 22 cases. Standard X-rays showed osteolysis in one case and bone sequestration in another. Staphylococcusaureus was identified in 10 cases. Surgery was performed in 17 cases. A subperiosteal abscess that required surgical drainage complicated 10 cases of osteomyelitis. No recurrence was observed. At the last follow-up, the median (range) age was 11.9 years (1.5-19). Sequelae (spontaneous tibia-talus fusion, first metatarsal epiphysis fusion, and varus deformity of the hindfoot) were observed in three cases, all of which were initially complicated by an abscess.

CONCLUSION

Physicians should be aware that pediatric BJIs of the lower limb may involve the foot and ankle. S. aureus is frequently involved. In cases of osteomyelitis, complications are closely associated with subperiosteal abscesses justifying an early diagnosis. These BJIs must be treated rapidly, and the risk of sequelae justifies long-term follow-up.

First case report of Cryptococcus laurentii knee infection in a previously healthy patient

BACKGROUND

The purpose of this case report was to report a case of Cryptococcus laurentii infection in the left knee of a previously healthy 29 year old male patient.

CASE PRESENTATION

After an initial misdiagnosis and 7 months of failed treatment, the patient received nearly a month of treatment with voriconazole (200 mg IV q12 h) and knee irrigation with amphotericin B until the infection was controlled. The treatment continued with fluconazole for nearly 7 months and approximately 5 weeks of antibiotic treatment for a skin bacterial coinfection. In the end, the patient's symptoms disappeared completely, the left knee recovered well, and there was no recurrence of infection.

CONCLUSION

The key points of successful treatment in this case were the thorough debridement, the adequate course of knee irrigation with antifungal drugs and more than 6 months of oral antifungal drugs that were able to eradicate the infection.

Update on Acute Bone and Joint Infections in Paediatrics: A Narrative Review on the Most Recent Evidence-Based Recommendations and Appropriate Antinfective Therapy

Acute bone and joint infections (BJIs) in children may clinically occur as osteomyelitis (OM) or septic arthritis (SA). In clinical practice, one-third of cases present a combination of both conditions. BJIs are usually caused by the haematogenous dissemination of septic emboli carried to the terminal blood vessels of bone and joints from distant infectious processes during transient bacteraemia. Early diagnosis is the cornerstone for the successful management of BJI, but it is still a challenge for paediatricians, particularly due to its nonspecific clinical presentation and to the poor specificity of the laboratory and imaging first-line tests that are available in emergency departments. Moreover, microbiological diagnosis is often difficult to achieve with common blood cultures, and further investigations require invasive procedures. The aim of this narrative review is to provide the most recent evidence-based recommendations on appropriate antinfective therapy in BJI in children. We conducted a review of recent literature by examining the MEDLINE (Medical Literature Analysis and Retrieval System Online) database using the search engines PubMed and Google Scholar. The keywords used were “osteomyelitis”, OR “bone infection”, OR “septic arthritis”, AND “p(a)ediatric” OR “children”. When BJI diagnosis is clinically suspected or radiologically confirmed, empiric antibiotic therapy should be started as soon as possible. The choice of empiric antimicrobial therapy is based on the most likely causative pathogens according to patient age, immunisation status, underlying disease, and other clinical and epidemiological considerations, including the local prevalence of virulent pathogens, antibiotic bioavailability and bone penetration. Empiric antibiotic treatment consists of a short intravenous cycle based on anti-staphylococcal penicillin or a cephalosporin in children aged over 3 months with the addition of gentamicin in infants aged under 3 months. An oral regimen may be an option depending on the bioavailability of antibiotic chosen and clinical and laboratory data. Strict clinical and laboratory follow-up should be scheduled for the following 3–5 weeks. Further studies on the optimal therapeutic approach are needed in order to understand the best first-line regimen, the utility of biomarkers for the definition of therapy duration and treatment of complications.

Septic Arthritis of the Pediatric Wrist: A Case Report and Review of the Literature

Septic arthritis of the wrist in pediatric patients is a rare diagnosis and is not well described in the literature. We present a case of a 4-month old patient with monoarticular septic arthritis of the wrist treated with surgical drainage and antibiotics. Although a rare diagnosis, septic arthritis of the wrist should be considered in patients with pseudoparalysis of the upper extremity and systemic signs of inflammation. Prompt diagnosis and treatment is critical to prevent permanent damage to the joint. Further data is needed to describe the epidemiology, microbiology, diagnostic findings and treatment of septic arthritis of the pediatric wrist.

Knee orthopedic problems in newborns and infancy: a review

PURPOSE OF REVIEW

We present the reader with insight on the most common disorders of the knee in newborns and infants. Knee issues in this population may confuse the first contact physicians due to certain peculiarities of the immature immune system, small size and underdevelopment of joint anatomy. Data presented here are recent and significant, and something to bear in mind when caring for children of this age.

RECENT FINDINGS

With the advent of new diagnostic methods, a shift in the causative agent of pediatric knee infections has been noted. Minimally invasive methods such as arthrocentesis and arthroscopy are successfully employed in treatment of knee problems in newborns and infants. A trial of conservative therapy in congenital patellar instability can give good results, and obviate the need for surgery in some cases. Various syndromes that affect the knee have specific characteristics that need to be recognized early to avoid problems in the future.

SUMMARY

Although rare, knee problems in infants can and do occur. Their cause varies significantly and good outcomes require a multidisciplinary approach. Early diagnosis, referral and initiation of treatment protocols can significantly influence the fate of the joint and with it the patients' functional status for life.

[Evaluation of the impact of the Spanish consensus document on the approach to osteoarticular infections in Spain through the Paediatrics Osteoarticular Infections Network (RIOPED)]

INTRODUCTION

In 2014 the Consensus Document produced by the Spanish Paediatric Societies (SEIP-SERPE-SEOP) was published to help in the diagnosis and treatment of osteoarticular infections (OAI). In 2015 the RIOPed was considered as a multidisciplinary national network for the investigation into OAI. The aim of this study was to assess the level of adaption to the recommendations established in the Consensus during one year of follow-up.

MATERIAL AND METHODS

A prospective, national multicentre study was carried out in 37 hospitals between September 2015 and September 2016. The study included patients >16years-old with a diagnosis of OAI, confirmed by microbiological isolation, or probable: septic arthritis (SA) with >40,000 white cells in synovial fluid, or osteomyelitis (OM)/spondylodiscitis (SD) with a compatible imaging test. The results were compared with those obtained in a retrospective study conducted between 2008 and 2012.

RESULTS

A total of 235 cases were included, of which 131 were OM, 79 SA, 30 OA, and 15 SD. As regards the complementary tests that the Consensus considered mandatory to perform, radiography was carried out on 87.8% of the cases, a blood culture on 91.6%, and culture of the synovial fluid in 99% of SA. A magnetic resonance (MR) was performed on 71% of the OM cases. The choice of intravenous empirical antibiotic treatment was adapted to the recommendations in 65.1% of cases, and in 62.3% for the oral treatment. Surgery was performed in 36.8% of SA cases (85.7% arthrotomy), with a significant decrease compared to the retrospective study (P=.014). Only 58.5% of cases followed the recommendations on the duration of the treatment; however, a lower duration of intravenous treatment was observed.

CONCLUSIONS

In general, the level of adaptation to the recommendations that were set by the Expert Group, is good for the complementary tests, and acceptable as regards the choice of antibiotic treatment, although inadequate in almost 40% of cases. A decrease in hospital stay was achieved.

Kingella kingae as the Main Cause of Septic Arthritis: Importance of Molecular Diagnosis

BACKGROUND

Kingella kingae is an emergent pathogen causing septic arthritis (SA) in children.The objective of this study was to analyze the etiology of SA in children before and after the implementation of universal 16S rRNA gene polymerase chain reaction and sequencing (16SPCR) in synovial fluid.

METHODS

Children ≤14 years with acute SA from a Madrid cohort (2002-2013) were reviewed. Differences in etiology were analyzed before (period 1) and after (period 2) the implementation of bacterial 16SPCR in 2009. A comparison in epidemiology, clinical syndromes, therapy and outcome between infections caused by K. kingae and other bacteria was performed.

RESULTS

Bacteria were detected from 40/81 (49.4%) children, with a higher proportion of diagnosis after 16SPCR establishment (period 2, 63% vs. period 1, 31.4%; P = 0.005). The main etiologies were Staphylococcus aureus (37.5%) and K. kingae (35%), although K. kingae was the most common microorganism in P2 (48.3%). Children with K. kingae SA were less likely to be younger than 3 months (0 vs. 42.3%; P < 0.001), had less anemia (21.4 vs. 50%; P = 0.010), lower C-reactive protein (3.8 vs. 8.9 mg/dL; P = 0.039), less associated osteomyelitis (0 vs. 26.9%; P = 0.033), shorter intravenous therapy (6 vs. 15 days; P < 0.001), and had a nonsignificant lower rate of sequelae (0 vs. 30%; P = 0.15) than children with SA caused by other bacteria. However, they tended to have higher rate of fever (86 vs. 57%; P = 0.083).

CONCLUSIONS

K. kingae was frequently recovered in children with SA after the implementation of bacterial 16SPCR, producing a milder clinical syndrome and better outcome. Therefore, the use of molecular techniques may be important for the management of these children.

Staphylococcus aureus osteoarticular infections in children: an 8-year review of molecular microbiology, antibiotic resistance and clinical characteristics

PURPOSE

To investigate the clinical, phenotypic and genotypic characteristics of Staphylococcus aureus strains causing osteoarticular infections in a large paediatric series.

METHODOLOGY

Medical records of children who were hospitalized with the diagnosis of community-associated S. aureus (CA-SA) osteomyelitis and/or septic arthritis in the two major tertiary paediatric hospitals of Athens during an 8-year period (2007-2015) were reviewed, and S. aureus isolates were analysed regarding antimicrobial resistance, detection of pathogenicity genes and genotyping using SCCmec, agr typing, PFGE and MLST.

RESULTS

During the study period, 123 children with CA-SA osteoarticular infections were identified, and methicillin-resistant S. aureus (MRSA) accounted for 44 of these (35.8 %). Children with MRSA infection had a significantly higher admission rate to the ICU (5.7  vs 0 %, P=0.04) and longer duration of hospitalization (21.6 vs 16.7 days, P=0.04). Sixty-eight isolates [42 (methicillin-sensitive S. aureus) MSSA and 26 MRSA] were available for molecular analysis. All MRSA strains were mecA-positive and most carried the SCCmec IV cassette (23/26, 88 %) and belonged to the PFGE type C (24/26, 92.3 %), agr type 3 (24/26, 92.3 %) and the MLST ST80 clone (24/26, 92.3 %). In contrast, MSSA strains showed polyclonality by PFGE and agr typing. Regarding pathogenicity genes, MRSA vs MSSA isolates showed higher detection rates of PVL (96.2 vs 4.8 %, P<0.0001) and fib (80.8 vs 50 %, P=0.02).

CONCLUSIONS

In our study a considerable number of S. aureus osteoarticular infections were due to CA-MRSA isolates, most of which belonged to the ST80 clone and had a higher incidence of specific virulence factors, entailing higher ICU admission rates and a longer duration of hospitalization.

Outpatients with acute osteoarticular infections had favourable outcomes when they received just oral antibiotics without intravenous antibiotics

AIM

The traditional approach for acute paediatric osteoarticular infections (OAI) has comprised initial intravenous antibiotics followed by prompt oral antibiotics. We assessed how providing just oral antibiotics compared to the traditional two-step approach.

METHODS

This prospective study was performed at the Hospital La Paz, Madrid, Spain, from September 2015 to September 2016. We compared 25 outpatients, with good general health and a mean age of 25 months who received just oral antibiotics, with 228 hospitalised children of a similar age who received intravenous and oral antibiotics from other hospitals in the Spanish Network of Osteoarticular Infections.

RESULTS

The groups were comparable in terms of age, sex, fever, erythrocyte sedimentation rate value, C-reactive protein and diagnosis. The oral group comprised 15 with osteomyelitis, seven with septic arthritis, two with osteoarthritis and one with spondylodiscitis. This group had a lower percentage of Staphylococcus aureus (8% vs 26%, p = 0.06) and higher proportion of Kingella kingae (24% vs 9%, p = 0.017) than the intravenous group. There were complications (24%) and follow-up sequelae (6%) in the intravenous group, but none in the oral group.

CONCLUSION

Outpatients with OAI who were in good general health had favourable outcomes when they received oral antibiotics without intravenous antibiotics.

Pediatric Methicillin-Resistant Staphylococcus aureus Osteoarticular Infections

Osteoarticular infections (OSI) are a significant cause of hospitalizations and morbidity in young children. The pediatric patient with OSI presents unique challenges in diagnosis and management due to higher morbidity, effect on growth plate with associated long-lasting sequelae, and challenges in early identification and management. Methicillin-resistant Staphylococcus aureus (MRSA), first described in the 1960s, has evolved rapidly to emerge as a predominant cause of OSI in children, and therefore empiric treatment for OSI should include an antibiotic effective against MRSA. Characterizing MRSA strains can be done by antimicrobial susceptibility testing, detection of Panton–Valentine leukocidin (PVL) gene, staphylococcal cassette chromosome mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). Worldwide, community-onset methicillin-resistant staphylococcal disease is widespread and is mainly associated with a PVL-producing clone, ST8/USA300. Many studies have implied a correlation between PVL genes and more severe infection. We review MRSA OSI along with the pertinent aspects of its pathogenesis, clinical spectrum, diagnosis, and current guidelines for management.

Risk factors associated with complications/sequelae of acute and subacute haematogenous osteomyelitis: an Italian multicenter study

BACKGROUND

Acute/subacute haematogenous osteomyelitis (AHOM/SAHOM) are potentially devastating diseases. Updated information about the epidemiology, management and outcome of AHOM/SAHOM is needed to minimize the risk of complications and sequelae.

METHODS

A multicenter study was performed to evaluate retrospectively the management and outcome of AHOM/SAHOM in Italy. Data from children aged >1 month, and hospitalized between 2010 and 2016, in 19 pediatric centers, were analyzed.

RESULTS

300 children with AHOM and 98 with SAHOM were included. Median age was 6.0 years (IQR: 2.0-11.0). No clinical difference was observed with the exception of fever at onset (63.0% vs. 42.9%; P < 0.0001), and a more common spinal involvement in SAHOM (6.7% vs 20.4%; P < 0.001). Fifty-Eight Staphylococcus aureus strains were isolated; 5 (8.6%) were MRSA. No Kingella kingae infection was documented. No different risk for complication/sequela was observed between AHOM and SAHOM (38.3% vs. 34.7%; OR:0.85; 95%CI: 0.53-1.38; P = 0.518). Duration and type of antibiotic therapy were not associated with risk of complication/sequelae.

CONCLUSION

AHOM and SAHOM displayed some differences, however occurrence and risk factors for complications and sequelae are similar, and the same empiric treatment might be recommended.

Neonatal Cervical Osteomyelitis With Bilateral Upper Limb Paresis

Neonatal cervical osteomyelitis is extremely rare, with only a few cases having been reported. We report a neonate with cervical osteomyelitis and extensive inflammation of the surrounded tissues that caused nerve root compression and upper limb paresis.

The Use of an "Internal Fixator Technique" to Stabilize Pathologic Fractures Developing Secondary to Osteomyelitis

BACKGROUND

There is no consensus on the materials and the techniques to use in fixing pathologic fractures secondary to osteomyelitis. This study reports the results of the fixation of pathologic fractures secondary to osteomyelitis using the "internal fixator technique."

METHODS

The internal fixator technique was performed on 11 children and adolescents with fractures secondary to osteomyelitis between 2003 and 2010. A retrospective chart review was conducted to record the following: age, sex, the anatomic region of infection, the time delay from symptom onset to fracture, the classification of chronic osteomyelitis, the Cierny-Mader classification, the causative organism, surgeries, the length of hospitalization, the location and the pattern of fracture, the duration of infection, the length of follow-up, and complications.

RESULTS

The patients included 7 male and 4 female patients with a mean age of 8.7 (range, 6 to 13) years. Pathologic fractures were as follows: 7 femur and 4 tibia. Nine of them were in the metaphysis and 2 others were located in the diaphysis. The time delay from symptom onset to fracture was 3.36 (1 to 9) months. The anatomic region of infection was the diaphysis in 2 cases and the metaphysis in 9 cases. Fractures patterns were short oblique and transverse. The length of hospitalization was a mean of 7 days. The duration of infection ranged from 1 to 12 (mean, 4.38) months. The mean duration of follow-up was 57.09 (range, 36 to 73) months from the initial presentation. Only 2 patients developed shortening, for which no additional intervention was performed.

CONCLUSIONS

This case series demonstrates that the "internal fixator technique" is an acceptable alternative to the management of pathologic fractures of the femur or the tibia in children and adolescents with unresolved acute and chronic osteomyelitis. Infections were resolved in all cases and fractures were sufficiently stabilized to allow union with a low complication rate.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Epidemiology and Management of Acute Haematogenous Osteomyelitis in a Tertiary Paediatric Center

Background: Paediatric acute hematogenous osteomyelitis (AHOM) is a serious disease requiring early diagnosis and treatment. To review the clinical presentation, management and organisms responsible for AHOM, and to explore risk factors for complicated AHOM, a large cohort referring to a single center over a 6-year period was evaluated. Methods: Data from children with AHOM, hospitalized between 2010 and 2015, and aged > 1 month, were retrospectively collected and analyzed. Results: 121 children (median age 4.8 years; 55.4% males) were included. Fever at onset was present in 55/121 children (45.5%); the lower limb was most frequently affected (n = 68/121; 56.2%). Microbiological diagnosis (by culture and/or polymerase chain reaction (PCR)) was reached in 33.3% cases. Blood and pus/biopsy culture sensitivities were 32.4% and 46.4%, respectively. PCR sensitivity was 3.6% (2/55) on blood, and 66.6% (16/24) on pus/biopsy sample. Staphylococcus aureus was the most commonly identified pathogen (n = 20); no methicillin-resistant Staphylococcus aureus (MRSA) was isolated, 10.0% (n = 2) strains were Panton-Valentine-Leukocidin (PVL) producer; 48.8% (59/121) cases were complicated. At univariate analysis, factors associated with complicated AHOM were: recent fever episode, fever at onset, upper limb involvement, white blood count (WBC) ≥ 12,000/µL, C reactive protein (CRP) ≥ 10 mg/L, S. aureus infection. At multivariate analyses S. aureus infection remained the only risk factor for complicated AHOM (aOR = 3.388 (95%CI: 1.061–10.824); p-value = 0.039). Conclusions: In this study microbiological diagnosis was obtained in over one third of cases. Empiric treatment targeting methicillin-sensitive Staphylococcus aureus seems to be justified by available microbiological data.

Group A Streptococcal Suppurative Arthritis and Osteomyelitis of the Shoulder With Brachial Plexus Palsy in a Newborn

Osteoarticular infections in the newborn period are rare. A serious complication is paralysis of the affected extremity resulting from either pain or direct involvement of the nerve. We report a newborn with combined osteomyelitis and suppurative arthritis caused by Streptococcus pyogenes presenting with right brachial plexus palsy.

Bacteremia in children: epidemiology, clinical diagnosis and antibiotic treatment

The diagnosis of bacteremia in children is important and it can be clinically challenging to recognize the signs and symptoms. The reported rates of bacteremia are higher in young children but with the increasing vaccine coverage, there has been a decrease in bacteremia due to the three vaccine preventable bacteria (Streptococcus pneumoniae, Haemophilus influenzae group b and Neisseria meningitidis). Notably, there have been increases in healthcare-associated bacteremias with a rise in Staphylococcus aureus and Gram negative bacteremias. This review provides a brief overview of the clinical diagnosis of bacteremia in children, focusing on the epidemiology, clinical characteristics, risk factors, antibiotic treatment, outcomes and preventative measures to reduce the incidence of bacteremia and improve morbidity and mortality.

Metaphyseal osteomyelitis in children: how often does MRI-documented joint effusion or epiphyseal extension of edema indicate coexisting septic arthritis?

BACKGROUND

Joint effusions identified by MRI may accompany osteomyelitis and determining whether the joint effusion is septic or reactive has important implications on patient care.

OBJECTIVE

Determine the incidence of epiphyseal marrow edema, joint effusions, perisynovial edema and epiphyseal non-enhancement in the setting of pediatric metaphyseal osteomyelitis and whether this may be used to predict coexisting septic arthritis.

MATERIALS AND METHODS

Following IRB approval, we retrospectively evaluated children who underwent MRI and orthopedic surgical consultation for suspected musculoskeletal infection between January 2011 and September 2013. Criteria for inclusion in the study were microbiologically/pathologically proven infection, MRI prior to surgical intervention, long bone involvement and age 0-18 years. MRI exams were independently reviewed by two faculty pediatric radiologists to confirm the presence of appendicular metaphyseal osteomyelitis, to evaluate extent of edema, to determine subjective presence of a joint effusion and to assess perisynovial edema and epiphyseal non-enhancement. Any discrepant readings were reviewed in consensus. Charts and operative notes were reviewed to confirm the diagnosis of osteomyelitis and septic arthritis.

RESULTS

One hundred and three joints with metaphyseal osteomyelitis were identified (mean age: 7.1 years; M:F 1.3:1), of whom 53% (55/103) had joint effusions, and of those, 75% (41/55) had surgically confirmed septic arthritis. The incidence of coexisting septic arthritis was 40% in the setting of epiphyseal edema, 74% in epiphyseal edema and effusion, 75% with perisynovial edema, 76% with epiphyseal non-enhancement and 77% when all four variables were present. Of these, the only statistically significant variable, however, was the presence of a joint effusion with a P-value of <0.0001 via Fisher exact test. Statistical significance for coexisting septic arthritis was also encountered when cases were subdivided into intra-articular vs. extra-articular metaphyses (P-value  =  0.0499). No statistically significant difference was found between patients younger than 24 months and those older than 24 months.

CONCLUSION

Patients with joint effusions identified by MRI, in the setting of metaphyseal osteomyelitis, should be presumed to have septic arthritis until proven otherwise. Epiphyseal extension of edema, perisynovial edema and epiphyseal non-enhancement in the setting of metaphyseal osteomyelitis are not helpful predictors in differentiating reactive and pyogenic joint effusions. Osteomyelitis at a site with an intra-articular metaphyses, however, is more likely to have concurrent septic arthritis.

Community-acquired bone and joint infections in children: a 1-year prospective epidemiological study

BACKGROUND

The incidence of childhood bone and joint infections (BJIs) is not well known, but is useful for identifying epidemiological differences and improving practice.

OBJECTIVE

To determine the incidence of BJI in previously well children and describe their clinical, laboratory and radiological characteristics.

DESIGN

A multicentre, population-based, prospective study performed from July 2008 through June 2009.

SETTING

Region of northern France with a population of 872 516 children <16 years old.

PATIENTS

All previously well children admitted in the region with septic arthritis, acute osteomyelitis or spondylodiscitis, diagnosed according to consensus criteria and after blinded radiological review.

MAIN OUTCOME MEASURES

The corrected incidence of BJI, determined with a capture-recapture method that used this prospective database and the discharge summary database.

RESULTS

58 cases were identified (median age: 3.6 years, range: 1 month-15.8 years; male to female ratio: 1.6). The completeness of the prospective database was 90%. The corrected incidence of any BJI was 7.1/100 000 children (95% CI 5.3 to 8.9). Thirty patients had septic arthritis (52%, incidence: 3.7/100 000; 95% CI 2.4 to 4.9), 24 osteomyelitis (41%, incidence 3.0/100 000; 95% CI 1.8 to 4.1), 4 spondylodiscitis (7%) and 0 osteoarthritis. Micro-organisms were identified from 15 patients (26%), with Staphylococcus aureus the most frequent organism. Radiological findings were characteristic of infection in 44% of BJI.

CONCLUSIONS

The corrected incidence of BJI in northern France, according to consensus diagnostic criteria, was 7.1/100 000 children <16 years of age.

Increasing pyomyositis presentations among children in Queensland, Australia

BACKGROUND

Pyomyositis, usually associated with tropical climates, occurs less commonly in temperate regions and is most often caused by Staphylococcus aureus. Several community-acquired methicillin-resistant S. aureus (CA-MRSA) clones have emerged in Queensland since the beginning of the century, and they now account for a significant proportion of invasive staphylococcal infection. This study aims to describe trends in the rate of presentation, and the clinical and diagnostic features of pyomyositis, and to determine if trends are attributed to the emergence of CA-MRSA or other factors.

METHODS

A 10-year retrospective cohort study of all patients presenting to Mater Children's Hospital in Brisbane, Queensland, with pyomyositis between July 2002 and July 2012, was conducted. Data were collected for clinical features, microbiology, diagnostic tests, management and outcome. Trends in incidence, and clinical and diagnostic features of pyomyositis were analyzed.

RESULTS

Thirty-four cases of pyomyositis were identified. There was a male predominance (79%), and the vertebro-pelvic muscles were most often affected. The rate of pyomyositis increased significantly during the study period from a rate of 2.04 cases per 10,000 emergency department admissions in the first quarter of the study, to 8.73 cases per 10,000 in the final quarter (peak rate 13.5 cases per 10,000 in 2008). A causative organism was identified in 22 cases, most commonly methicillin-susceptible S. aureus with CA-MRSA identified in 4 cases. Patients who required surgical intervention had longer hospital admission, longer time to resolution of inflammatory markers and a higher risk of complication at follow-up.

CONCLUSION

This study demonstrates an increasing incidence of pyomyositis in a temperate region, which is not attributable to the emergence of CA-MRSA. The reasons for this change in incidence are not clear.

[SEIP-SERPE-SEOP Consensus document on the treatment of uncomplicated acute osteomyelitis and septic arthritis]

This is a Consensus Document of the Spanish Society of Paediatric Infectious Diseases (Sociedad Española de Infectología Pediatrica), Spanish Society of Paediatric Rheumatology (Sociedad Española de Reumatología Pediátrica) and the Spanish Society of Paediatric Orthopaedics (Sociedad Española de Ortopedia Pediátrica), on the treatment of uncomplicated acute osteomyelitis and septic arthritis. A review is presented on the medical and surgical treatment of acute osteoarticular infection, defined as a process with less than 14 days of symptomatology, uncomplicated and community-acquired. The different possible options are evaluated based on the best available scientific knowledge, and a number of evidence-based recommendations for clinical practice are provided.

Preceding trauma in childhood hematogenous bone and joint infections

Preceding trauma may play a role in the etiology and pathogenesis of hematogenous bone and joint infections. Among 345 children with an acute hematogenous bone and/or joint infection, 20% reported trauma during a 2-week period leading to infection. Blunt impact, bruises, or excoriations were commonly reported. The rate was similar to that in the general pediatric population obtained from the literature. In the study group, patients with and without trauma were similar in age, serum C-reactive protein and erythrocyte sedimentation rate, length of hospitalization, and late sequelae. Preceding minor trauma did not prove to be significant as an etiological or as a prognostic factor.

X-linked agammaglobulinemia combined with juvenile idiopathic arthritis and invasive Klebsiella pneumoniae polyarticular septic arthritis

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations in the Bruton's tyrosine kinase (BTK) gene. XLA can also present in combination with juvenile idiopathic arthritis (JIA), the major chronic rheumatologic disease in children. We report herein the first known case of a juvenile patient diagnosed with XLA combined with JIA that later developed into invasive Klebsiella pneumoniae polyarticular septic polyarthritis. An additional comprehensive review of XLA combined with JIA and invasive K. pneumoniae septic arthritis is also presented. XLA was identified by the detection of BTK mutations while the diagnosis of JIA was established by clinical and laboratory assessments. Septic arthritis caused by invasive K. pneumoniae was confirmed by culturing of the synovia and gene detection of the isolates. Invasive K. pneumoniae infections can not only result in liver abscesses but also septic arthritis, although this is rare. XLA combined with JIA may contribute to invasive K. pneumoniae infection.

Clinical management of septic arthritis in cattle

Synovial fluid, ultrasound, and radiographic imaging are common diagnostic tools for septic arthritis. Mycoplasma septic arthritis is suspected in calves with clinical signs of otitis and pneumonia. Commonly affected joints are carpus, stifle, and tarsus. Treatment strategy must include long-term antibiotics, anti-inflammatories, and joint lavage. Knowledge of communication and boundaries for commonly affected joints is essential to perform joint lavage and arthrotomy.