Pediatric musculoskeletal infections.

PURPOSE OF REVIEW: The aim of this article is to review the recent guidelines and literature regarding the diagnosis and the treatment of common pediatric musculoskeletal infections: septic arthritis, osteomyelitis, pyomyositis, and Lyme disease. RECENT FINDINGS: In the last decade, a better understanding of the causative organisms of common bacterial infections, including Kingella , leads to prompt targeted antimicrobial coverage in all musculoskeletal infections. Prompt diagnosis and treatment continues to be the mainstay in the treatment of children with osteoarticular infections. Efforts to improve early detection have lead to improving rapid lab diagnostic testing; however, more advanced diagnostics such as arthrocentesis for septic arthritis and MRI for osteomyelitis and pyomyositis, remain the gold standard. Shorter and narrowed antibiotic courses, with appropriate transition to outpatient oral treatment provide effective infection clearance and reduction in complications of disease. SUMMARY: Advances in diagnostics, including pathogen identification as well as imaging continues to improve our ability to diagnose and treat these infections, although still lack ability to provide definitive diagnosis without more invasive nor advanced techniques.

Multifocal neuropathy and Horner's syndrome due to disseminated pyomyositis in an intravenous drug user.

BACKGROUND: The formation of abscesses with necrosis within large, striated muscles leads to pyomyositis, a condition relatively rarely encountered outside the tropics. Intravenous drug users and other immunocompromised individuals are predisposed toward this infection, which may occur due to local or haematogenous spread of infection to skeletal muscles previously damaged by trauma, exercise, or rhabdomyolysis. METHODS: We report a young male intravenous drug user with rhabdomyolysis due to use of a synthetic opioid, in whom disseminated pyomyositis was detected following evaluation for sciatic and radial neuropathies and Horner's syndrome and review available reports of peripheral nerve dysfunction in the setting of this uncommon infection. We searched online databases to identify all published reports on adult patients with pyomyositis complicated by peripheral nerve dysfunction. CONCLUSIONS: Peripheral nerve dysfunction may rarely occur via local spread of infection or compression from abscesses.

A prospective study on skin and soft tissue infections: a fact-finding mission from a tertiary centre in north India.

OBJECTIVE: Despite the high prevalence and poor outcome of skin and soft tissue infections (SSTIs), very few studies from India have dealt with the subject. We planned a prospective study of inpatients with SSTIs to study the aetiology, clinical presentation (severity) and outcome of patients with SSTIs in our facility. METHOD: Patients with SSTIs involving >5% body surface area (BSA) and/or systemic signs were admitted to the surgery department of a teaching tertiary level hospital in Delhi, India, and were clinically classified into cellulitis, necrotising soft tissue infections (NSTIs), pyomyositis, and abscess. Demographic and clinical variables such as: age; sex; occupation; history of trauma/insect or animal bites; duration of illness; presenting symptoms and signs; comorbid conditions; predisposing factors such as lymphoedema or venous disease; hospital course; treatment instituted; complications; hospital outcome; presence of crepitus, bullae, gangrene, muscle necrosis and compartment syndrome were recorded. The chief outcome parameters were death and length of hospital stay; others, such as abscess drainage, the need for plastic surgical procedures and amputations were also noted. RESULTS: Out of 250 patients enrolled in the study, 145 (58%) had NSTIs, 64 (26%) had abscesses, 15 (6%) had cellulitis and 26 (10%) had pyomyositis. Mortality was observed with NSTIs (27/145, 19%) and with pyomyositis (3/26, 11.5%). Factors affecting mortality by univariate analysis in the NSTI group were: abnormal pulse; hypotension; tachypnea; bullae; increased blood urea and serum creatinine; inotrope or ventilator support (all with p<0.001); local tenderness, gangrene, dialysis support and BSA (9.33±6.44 versus 5.12±3.62; p<0.05 for the last four). No factor was found to be significant on multivariate analysis. Variables associated with hospital stay >12 days were immunocompromise, pus discharge, ulceration or gangrene, and after interventions such as blood transfusion, drainage or skin grafting. CONCLUSION: High prevalence of NSTI and pyomyositis with high mortality was observed in our SSTI patients, often in immunocompetent young individuals. Epidemiological studies focused on virulent strains of Staphylococcus aureus may be required to identify the cause, since Staphylococcal toxins have been implicated in other infections.

A Clinical Prediction Rule for Bacterial Musculoskeletal Infections in Children with Monoarthritis in Lyme Endemic Regions.

STUDY OBJECTIVE: Children with a bacterial musculoskeletal infection (MSKI) require prompt identification and treatment. In Lyme disease endemic areas, children with an MSKI can present similarly to those with Lyme arthritis. Our goal was to derive a clinical prediction rule to accurately identify children at a low risk for an MSKI. METHODS: We enrolled children with monoarthritis presenting to 1 of 6 Pedi Lyme Net centers and performed a procalcitonin (PCT) and a first-tier Lyme C6 enzyme immunoassay (EIA) test. Our primary outcome was an MSKI (septic arthritis, osteomyelitis, or pyomyositis). Using recursive partitioning with k-fold cross validation, we derived a clinical prediction rule to identify children at a low risk of an MSKI. We calculated the accuracy of our novel rule in a derivation cohort. RESULTS: Of the 735 children in the derivation cohort with an available research biosample, 39 (5%) had an MSKI (18 had septic arthritis, 20 had osteomyelitis, and 1 had pyomyositis), 260 (37%) had Lyme arthritis, and 436 (53%) had other inflammatory arthritis. Children with a PCT level of more than or equal to 0.50 ng/mL and those with a C-reactive protein (CRP) level of more than or equal to 0.6 mg/dL with a negative Lyme C6 EIA were classified as not low risk for an MSKI. Of the 451 (61%) children categorized as low risk, none had an MSKI (sensitivity 100%, 95% confidence interval 91.0% to 100%; specificity 74.2%, 95% confidence interval 70.5% to 77.6%). CONCLUSION: A novel clinical decision rule that includes PCT, CRP, and a first-tier Lyme EIA was highly sensitive for MSKIs. Although broader external validation is required, the application of this rule may safely reduce invasive testing, procedures, and treatment for low risk children.

Transient synovitis of the hip: Current practice and risk of misdiagnosis.

INTRODUCTION: Transient synovitis (TS) is a common and benign cause of hip pain in children, but must be distinguished from more serious entities such as septic arthritis, osteomyelitis, and pyomyositis. Our objectives were to determine the risk of missed bacterial musculoskeletal infection and rates of diagnostic testing in children diagnosed with TS. METHODS: We performed a cohort study using the Pediatric Heath Information System of children 1-10 years diagnosed with TS in the ED. We determined rates of missed bacterial musculoskeletal infection (defined as a new diagnosis of septic arthritis, osteomyelitis, or pyomyositis within 14 days of initial ED visit). We described the initial diagnostic evaluation and ED management of children diagnosed with TS and variability between sites. RESULTS: We analyzed 6419 encounters from 37 hospitals. 62 (1.0%, 95%CI: 0.7-1.2%) children were diagnosed with a missed bacterial musculoskeletal infection. Children with missed infection were younger than those without (median age 2.6 vs. 4.6 years, p < 0.01). Serum laboratory testing was performed in 76% of encounters with minimal variation across sites. There was significant variation in the rates of hip ultrasound by site (2 to 92%), which has increased in use over time (from 42% in 2016 to 62% in 2021). CONCLUSION: In this large observational study, missed bacterial musculoskeletal infection in children diagnosed with TS was rare but more common in younger children. The optimal combination of bloodwork and radiographic testing, especially ultrasound, to distinguish TS from more serious disease remains unclear.

Point-of-Care Ultrasound Identifies Pyomyositis Secondary to Intramuscular Testosterone Injection: Report of Two Cases.

BACKGROUND: Intramuscular (i.m.) injections are a commonly utilized route for medication delivery. Intramuscular-associated soft tissue infections are rare and can include pyomyositis and i.m. abscess. Intramuscular testosterone injections have not been previously implicated in causing pyomyositis. Point-of-care ultrasound is an important bedside tool that can identify pyomyositis and differentiate this infection from more common entities such as cellulitis. CASE REPORTS: We present two cases of i.m. testosterone-associated pyomyositis. In both cases, the physical examination features were consistent with simple cellulitis. However, point-of-care ultrasound evaluation revealed changes consistent with pyomyositis in each case. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although uncommon, i.m. injections such as testosterone carry a risk of soft tissue infection. As demonstrated in the above cases, ultrasound can be helpful in making the differentiation between simple cellulitis and pyomyositis. The emergency physician should be cognizant of this complication of therapeutic i.m. injections, as well as the diagnostic efficacy of point-of-care ultrasound in evaluating the extent and location of the soft tissue infection.

Meticillin-susceptible Staphylococcus aureus pyomyositis and cellulitis in right thigh of a 15-year-old boy: a case study.

Pyomyositis is a purulent infection of striated muscle and postoperative management remains the mainstay. If delayed primary wound closure is not managed in a timely manner, it often results in recurrent infection and sinus tract creation. Cavity wounds with sinus formation are known to complicate treatment, are problematic to manage and persist for long periods of time. The aim of this case report is to present the challenges in the assessment and management of a sinus tract with deep cavity wound, between the vastus lateralis and biceps femoris muscles, originating from liquefaction of a haematoma. Our review of the literature revealed limited research evidence in the management of deep cavity wounds. This is a rare case where the sinus tract route which leads to the rim-shaped cavity is embedded deep between the muscles, posing a high risk of recurrent infection from the premature closure of the wound tract. Successful management was attributed to: the accuracy in the initial wound assessment; appropriate dressing plans; the rationale for each action; and an outcome goal as each treatment progressed. Daily dressing change and reassessment of the wound was required to ensure progress and to address any complications in a timely manner. Finally, concerns of the patient and their family and regular discussions on the treatment plans are important to encourage adherence with management goals.

Invasive Hypervirulent Klebsiella pneumoniae Syndrome Originating from an Anorectal Abscess as Opposed to a Pyogenic Liver Abscess.

An immunocompetent 49-year-old man presented with swelling and pain in the lower region of his left leg that had lasted for 4 weeks. The diagnosis was severe pyomyositis and osteomyelitis in the lower left leg caused by hypervirulent Klebsiella pneumoniae (hvKP) along with multiple metastatic infections in the kidneys, lungs, and brain originating from an anorectal abscess. A virulence-gene analysis revealed that the isolated K. pneumoniae harbored rmpA, entB, ybtS, kfu, iutA, mrkD, and allS-virulence genes and belonged to the K1 capsular serotype. After repeated abscess drainage procedures, intravenous ceftriaxone was administered for more than 10 weeks, and the patient's infection was controlled. We focused on the clinical features of hvKP originating from an anorectal abscess without a pyogenic liver abscess. We suggest that hvKP be considered a causative pathogen of pyomyositis and osteomyelitis resulting in multiple metastatic infections in an immunocompetent patient, and more information on the unexpected multiple metastatic infections should be obtained from a virulence analysis of K. pneumoniae.

Factors associated with pyomyositis: A systematic review and meta-analysis.

OBJECTIVES: Pyomyositis, an acute bacterial infection of skeletal muscle usually resulting in abscess formation, is well recognised in tropical regions where it can account for up to 4% of adult surgical admissions. It is increasingly being reported from high-income temperate countries. Pyomyositis occurs across all ages and in both sexes. Mortality ranges from 1% to 23%. Many risk factors have been suggested. We aimed to identify factors associated with pyomyositis. METHODS: We undertook a systematic review and meta-analysis, using PubMed, EMBASE, Scopus and the Cochran Library and hand-searching published papers. The random-effects model meta-analysis was used to calculate pooled estimated odd ratios with the corresponding 95% confidence interval. RESULTS: All studies in the systematic review (n = 25) and the meta-analysis (n = 12) were hospital-based. Seven only included children. Relatively few studies have been published in the last decade, the majority of which are from high-income temperate settings. Staphylococcus aureus was the main organism isolated. Males under the age of 20 predominated, and mortality of up to 20% was reported. Factors associated with pyomyositis were HIV infection (OR = 4.82; 95% CI: 1.67-13.92) and fulfilling an AIDS surveillance definition (OR = 6.08; 95% CI: 2.79-13.23). CONCLUSIONS: Our meta-analysis indicated significant associations between pyomyositis infection and HIV/AIDS. Major gaps in our understanding of the epidemiology, pathogenesis, clinical presentation, and outcome remain, highlighting the need for further research and more systematic studies. Pyomyositis merits consideration as a neglected tropical disease.

Pseudomonas aeruginosa Pyomyositis in a Child With Acute Lymphoblastic Leukemia: A Case Report and Review of Literature.

BACKGROUND: We report the case of an 11-year-old girl with a recent diagnosis of common B-cell acute lymphoblastic leukemia who presented with Pseudomonas aeruginosa pyomyositis of the left lower limb during severe neutropenia associated with the induction phase of chemotherapy. OBSERVATIONS: Presenting signs included fever, leg pain, and refusal to walk. Popliteal knee ultrasonography was unremarkable, whereas magnetic resonance imaging showed 2 intramuscular fluid collections requiring surgically drainage. CONCLUSION: A review of medical literature showed that pyomyositis is an infrequent complication in children with hematological malignancies, and most cases are due to Staphylococcus aureus, whereas Pseudomonas aeruginosa appears to be rarely involved.

Primary Bacterial Pyomyositis in Children: A Systematic Review.

BACKGROUND: Tropical pyomyositis has had a recent increase in the United States, Europe, and other nontropical areas. The purpose of this study was to provide an accurate description of the demographics, presenting features, sites of involvement, microbiology, imaging modalities, medical and surgical management, complications, and predictors of clinical course. METHODS: We searched PubMed, Cochrane, Web of Science Collection, Scopus, and Embase databases yielding 156 studies. Of these, 23 articles were selected for statistical analysis. RESULTS: The average age at presentation was 8.4±1.9 years with males more commonly affected. Fever, painful limp, and localized pain were the most common presenting symptoms. Pelvis, lower extremity, trunk and spine, in descending order, were the most commonly affected locations. Iliopsoas, obturator musculature, and gluteus musculature were the most commonly affected muscle groups. The mean time to diagnosis was 6.6±3.05 days. Staphylococcus aureus was the most common offending organism. The mean length of hospital stay was 12.0±4.6 days. Medical management alone was successful in 40% of cases (143/361) with an average duration of 9.5±4.0 and 22.7±7.2 days of intravenous and oral antibiotics, respectively. Surgical management consisted of open drainage in 91.3% (199/218) or percutaneous drainage in 8.7% (19/218) of cases. Painful limp, fever, and larger values of white cell count and erythrocyte sedimentation rate were associated with an increased need for surgery. Obturator and calf muscle involvement were strongly associated with multifocal involvement. There were 42 complications in 41 patients (11.3%). Methicillin-resistant S. aureus was associated with an increased risk of complications. The most common complications were osteomyelitis, septicemia, and septic arthritis. CONCLUSIONS: Primary pyomyositis should be considered in cases suggesting pediatric infection. Magnetic resonance imaging is the most commonly used imaging modality; however, ultrasound is useful given its accessibility and low cost. Medical management alone can be successful, but surgical treatment is often needed. The prognosis is favorable. Early diagnosis, appropriate medical management, and potential surgical drainage are required for effective treatment. LEVEL OF EVIDENCE: Level IV-systematic review.

Multifocal extraocular muscle pyomyositis: A case report and review of literature.

Pyomyositis is a rare condition which occurs most often in large skeletal muscles. Pyomyositis of extraocular muscles is a very rare entity. The authors describe a case of 2 sites of pyomyositis of extraocular muscles. A 20-year-old man presented with right periocular pain, redness, and proptosis for 1 week.Computed tomography showed well-circumscribed masses with enhancing rims in the medial and inferior rectus muscles. The patient underwent orbital drainage surgery and received an intravenous antibiotic. Haemoculture and pus culture could not identify an organism. Systemic steroid was administered after the infection was controlled, in regard to scar prevention.

Tropical pyomyositis: an update.

Tropical pyomyositis (TP) is a life-threatening bacterial infection of the skeletal muscle that occurs particularly among children, young adults and those with immunocompromised conditions. The appropriate diagnosis and treatment are often delayed due to its non-specific signs, leading to fatal consequences. Staphylococcus aureus, especially methicillin-susceptible S. aureus, is responsible for most TP cases. However, other bacteria (i.e. streptococci, Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., Candida spp., Mycobacterium spp.) have been reported. This narrative review provides an update on the epidemiology and clinical course of TP. A special focus is laid on the role of toxins (i.e. Panton-Valentine Leucocidin and α-toxin) in the pathogenesis of TP and their implication for the clinical management of infection.

La pyomyosite tropicale (TP) est une infection bactérienne potentiellement mortelle du muscle squelettique qui survient particulièrement chez les enfants, les jeunes adultes et les personnes immunodéprimées. Le diagnostic et le traitement appropriés sont souvent retardés en raison de ses signes non spécifiques, entraînant des conséquences fatales. Staphylococcus aureus, en particulier S. aureus sensible à la méthicilline, est responsable de la plupart des cas de TP. Cependant, d'autres bactéries (ex: streptocoques, Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., Candida spp., Mycobacterium spp.) ont été rapportées. Cette revue narrative fournit une mise à jour sur l'épidémiologie et l'évolution clinique du TP. Un accent particulier est mis sur le rôle des toxines (la Leukocidine de Panton-Valentine et l'α-toxine) dans la pathogenèse du TP et leur implication pour la prise en charge clinique de l'infection.

Pyomyositis and muscle abscess due to Salmonella enteritidis in a patient with Behçet's syndrome: a case report.

Salmonella infections usually present with gastrointestinal manifestations including enterocolitis especially in immunocompromised patients. Haematogenous dissemination and abscesses are very rare complications of Salmonella species. This case report documents a patient with Behçet's syndrome (BS) who has pyomyositis due to Salmonella species. A 43-year-old male patient with BS presented to the outpatient rheumatology clinic with bilateral acute-onset lower extremity pain. However, over a short time the pain gradually increased and was accompanied by fever. The magnetic resonance scans demonstrated pyomyositis and muscle abscess in the adductor and obturator muscles. The cultures showed Salmonella enteritidis infection. The patient was successfully treated with antibiotic therapy. This case is important since it is one of the first in the literature to report an adult patient with BS and Salmonella pyomyositis.

Point-of-Care Ultrasound to Diagnose Pyomyositis in a Child.

We report a case of a patient presenting with fever, right lower leg swelling, and pain who was found to have a fluid collection between muscle planes noted on point-of-care ultrasound. Point-of-care ultrasound raised the clinician's concern for deep musculoskeletal infection, leading to prompt initiation of antibiotics and magnetic resonance imaging.

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.

Staphylococcus aureus-Associated Musculoskeletal Infections.

Musculoskeletal infections caused by Staphylococcus aureus are among the most difficult-to-treat infections. S. aureus osteomyelitis is associated with a tremendous disease burden through potential for long-term relapses and functional deficits. Although considerable advances have been achieved in diagnosis and treatment of osteomyelitis, the management remains challenging and impact on quality of life is still enormous. S. aureus acute arthritis is relatively seldom in general population, but the incidence is considerably higher in patients with predisposing conditions, particularly those with rheumatoid arthritis. Rapidly destructive course with high mortality and disability rates makes urgent diagnosis and treatment of acute arthritis essential. S. aureus pyomyositis is a common disease in tropical countries, but it is very seldom in temperate regions. Nevertheless, the cases have been increasingly reported also in non-tropical countries, and the physicians should be able to timely recognize this uncommon condition and initiate appropriate treatment. The optimal management of S. aureus-associated musculoskeletal infections requires a strong interdisciplinary collaboration between all involved specialists.

Concurrent methicillin-resistant Staphylococcus aureus septicemia and pyomyositis in a patient with dengue hemorrhagic fever: a case report.

BACKGROUND: Concurrent presence of dengue hemorrhagic fever (DHF), tropical pyomyositis and septicemia due to methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy person has never been reported. These three conditions even individually are potentially fatal. "Here we describe a case of a patient contracting dengue and developing DHF along with concurrent pyomyositis likely to be due to MRSA, leading to MRSA septicemia with abscesses formed by MRSA". CASE PRESENTATION: A 44-year old previously healthy Sinhalese man presented on day 3 of the illness with fever, headache, arthralgia and myalgia and watery loose stools. His pulse rate was 76/min, blood pressure was 110/80 mmHg, while cardiovascular, respiratory and abdomen examination findings were unremarkable. The test for the dengue NS1 antigen was positive on the same day. We have diagnosed dengue and started managing him symptomatically as per the current national guidelines. The patient developed DHF with bilateral pleural effusion and ascitis. On the day 5 he developed severe myalgia, tenderness and non pitting edema of lower limbs especially in the thighs. His creatine kinase levels were high and an ultrasound scan confirmed myositis of both thighs. We suspected myositis due to dengue but investigated for possible simultaneous sepsis as well. On day 9 his blood culture became positive for MRSA. Considering the sensitivity of the bacteria intravenous vancomycin and ciprofloxacin was administered for 21 days. He developed a small abscess at the site of the first intravenous access and a large one above the ankle on the left. On day 12 the latter was drained and the pus culture yielded MRSA sensitive to the same antibiotics. The rapid test for dengue IgM was negative initially but later a positive MAC-ELISA test entrenched dengue infection. After improvement he was sent home on day 33 of the illness. He has developed two other abscesses in the proximity of the drained one and they were drained on day 57. The patient recovered. CONCLUSIONS: When dengue patients develop symptoms and signs of myositis, prompt investigations for pyomyositis and the treatment can save lives.