Pyomyositis in Children

Arthritis or an Adjacent Fascial Response? A Case Report of Combined Pyomyositis and Aseptic Arthritis

Pyomyositis, accompanied by aseptic arthritis, has been previously documented in several publications. However, none of the authors in the mentioned case reports offered a pathophysiological explanation for this unusual phenomenon or proposed a treatment protocol. We present a case of a healthy, 70-year-old male who was presented to the emergency department 4 days after tripping over a pile of wooden planks and getting stabbed by a nail to his thigh. The right thigh was swollen. Unproportional pain was produced by a light touch to the thigh. A laboratory test and a CT scan were obtained. The working diagnosis was pyomyositis of the thigh and septic arthritis of the ipsilateral knee. The patient underwent urgent debridement and irrigation of his right thigh. An arthroscopic knee lavage was performed as well. Intraoperative cultures from the thigh revealed the growth of Streptococcus pyogenes and Staphylococcus aureus. Cultures from synovial fluid were sterile; thus, septic arthritis was very unlikely. The source of the knee effusion might have been an aseptic inflammatory response due to the proximity of the thigh infection. Anatomically, the quadriceps muscle inserts on the patella, and its tendon fuses with the knee capsule, creating a direct fascial track from the thigh to the knee. The inflammatory response surrounding the infection may have followed this track, creating a domino effect, affecting adjacent capillaries within the joint capsule, and causing plasma leakage into the synovial space, leading to joint effusion. Our suggested treatment is addressing the primary infection with antibiotics and considering adding anti-inflammatory therapy, given our suspicion that this process has an inflammatory component.

Clinical Characteristics and Management of Children and Adolescents Hospitalized With Pyomyositis

BACKGROUND

Pyomyositis, a bacterial muscle infection, is an important differential diagnosis in children and adolescents with musculoskeletal pain. In contrast to tropical regions, it is rarely recognized in temperate countries, but incidence is increasing and major studies are missing.

METHODS

This retrospective multicenter study included patients <18 years of age hospitalized with pyomyositis in 11 Swiss children's hospitals between January 2010 and December 2022. Cases were identified by ICD-10 code (Myositis; M60-M60.9), and data was extracted from electronic hospital records.

RESULTS

Of 331 patients identified, 102 fulfilled the case definition. Patient age at presentation ranged from 2 weeks to 17 years (median 8 years). The majority had no underlying illness and all presented with fever and localized pain. At the respective site of pyomyositis, 100 (98%) had impaired movement and 39 (38%) presented with local swelling. Pelvic (57%) and leg (28%) muscles were mostly affected. Blood or tissue cultures were obtained in 94 (92%) and 59 (57%) patients, respectively. Of those, 55 (58%) blood and 52 (88%) tissue cultures were positive, mainly for Staphylococcus aureus (35 and 19, respectively) and Streptococcus pyogene s (12 and 15, respectively). All patients received antibiotic treatment during hospitalization for a median of 10 days (interquartile range: 7-17), followed by outpatient treatment for a further median of 16 days (interquartile range: 11-22) in 95 (93%) patients. Fifty-nine (57%) patients required surgery.

CONCLUSIONS

Pyomyositis is a challenging diagnosis that requires a high level of awareness. Blood and/or tissue cultures revealed S. aureus and S. pyogenes as the predominant causative agents.

Changing spectrum of primary pyomyositis in North India

Recent data have demonstrated the changing epidemiology of primary pyomyositis worldwide. Our hospital-based retrospective study investigated the clinical and microbiological spectrum of primary pyomyositis between 2013 and 2021 in PGIMER (Chandigarh), India. Over a quarter had predisposing conditions, mainly diabetes mellitus and immunosuppressive therapy. Fever, muscle pain, local swelling and breathlessness were the usual presentations, with quadriceps, iliopsoas and gluteal muscles commonly affected. Staphylococcus aureus was the predominant cause, with c.50% methicillin-resistant strains. Almost two-thirds presented with metastatic infection (stage 3 pyomyositis), frequently with septic lung emboli. Patients with methicillin-sensitive and resistant Staphylococcus aureus had a similar incidence of metastatic infection. In-hospital mortality was c.10% and was strongly associated with a high international normalised ratio. Primary pyomyositis remains a significant problem, with a dramatic increase in community-associated methicillin-resistant Staphylococcus aureus.

A fatal case of paediatric post-traumatic pyomyositis

A 6-year-old girl was brought to the emergency department with a history of an accidental fall a few days earlier. She presented with a fever, cough and constipation. Sars-CoV-2 infection being suspected, she was transferred to a paediatric facility for Covid-positive patients. During the diagnostic process, the clinical picture suddenly deteriorated with the development of bradycardia, tachypnea and altered sensorium. Despite cardiopulmonary resuscitation attempts, the child died about 16 hours after admission to the emergency department. A judicial forensic autopsy was performed that concluded that her death was due to multiple acute pulmonary, cardiac and renal infarctions secondary to septic thromboembolism in the course of post-traumatic bacterial necrotizing pyomyositis of the right ileo-psoas muscle.

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.

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.

A Severe Systemic Infection in a 14-Year-Old Boy That Took Place during the COVID-19 Pandemic

Introduction: Since March 2020, the COVID-19 pandemic has been a global talking point. Access to health care has become more difficult, and such an obstacle increase the risk of inadequate medical care, especially among paediatric patients. Case: This report describes the case of a previously healthy teenager who was staying home for 2 months due to a strict lockdown period in the COVID-19 pandemic and was admitted to hospital for fever, nausea and lumbar pain. He was diagnosed consecutively with meningitis, sepsis, paraspinal abscesses and endocarditis. Further investigation did not reveal any risk factors or immunodeficiency in the patient. Discussion: Sepsis is defined as the presence of systemic inflammatory response syndrome (SIRS) associated with a probable or documented infection. It is the leading cause of death from infection, especially if not recognized and treated quickly. Sepsis may lead to various complications, such as infective endocarditis, meningitis and abscesses. Although such complications may initially be latent, they can promote internal organ dysfunction and the possibility of their presence should be considered in any patient with systemic infection. Any child with a fever should be treated as one with the possibility of developing a severe infection. Conclusion: The presented case shows that even a previously healthy child staying in long-term home isolation can develop a severe infection with multiorgan complications, and the COVID-19 pandemic should not extend the diagnostic process in patients with symptoms of infection.

Pelvic Pyomyositis in Childhood: Clinical and Radiological Findings in a Tertiary Pediatric Center

Pyomyositis (PM) is an infrequent but increasing bacterial infection of the skeletal muscle, with muscles of the pelvis and thigh frequently involved. The diagnosis is often challenging, especially when a deep muscle is affected. We present a single-center pediatric cohort affected by pelvic PM. A retrospective analysis was performed, including children admitted to Meyer Children’s Hospital between 2010 and 2020. Demographic, anamnestic, clinical, laboratory, radiological and management data were collected. Forty-seven patients (range 8 days–16.5 years, 66% males) were selected. Pain (64%), functional limitations (40%) and fever (38%) were the most common presenting symptoms; 11% developed sepsis. The median time to reach the diagnosis was 5 days (IQR 3–9). Staphylococcus aureus was the most common organism (30%), Methicillin-Resistant S aureus (MRSA) in 14%. PM was associated with osteomyelitis (17%), arthritis (19%) or both (45%). The infection was multifocal in 87% of children and determined abscesses in 44% (40% multiple). Pelvic MRI scan, including diffusion-weighted imaging (DWI), always showed abnormalities when performed. Clinical and laboratory findings in pelvic PM are unspecific, especially in infancy. Nevertheless, the infection may be severe, and the suspicion should be higher. MRI is the most useful radiological technique, and DWI sequence could reveal insidious infections.

Primary Pyomyositis Caused by Kingella kingae in a 21-Month-old Infant: A Case Report

The authors report a rare case of an unusual primary pyomyositis of the biceps cruralis assigned to Kingella kingae in a 21-month-old girl. The reported case demonstrated that primary pyomyositis may be encountered during invasive infection due to K. kingae even if this manifestation remains rare. This bacterial etiology must, therefore, be evoked when a primary pyomyositis is observed, and this is in particular in children under 4 years of age.

Fulminant Necrotizing Pyomyositis Tropicans

Pyomyositis tropicans is a purulent invasive infection of the striated muscle tissues, usually caused by Gram-positive bacteria Staphylococcus aureus and Streptococcus in immunocompromised patients. We hereby report a case of fulminant necrotizing pyomyositis that occurred in a 16-year-old immunocompetent patient, and it is the first one of its kind to the best of our knowledge. The patient underwent imaging which suggested extensive intramuscular abdominal wall abscess formation, for which the patient underwent multiple surgical debridements of the lateral thoracic wall. Subsequent cultures grew Escherichia coli as the causative organism. Postoperatively, the patient went into catastrophic, irreversible septic shock ending in an eventual fatality.

Extensive pyomyositis secondary to paronychia-related MRSA infection: A case report

RATIONALE

Pyomyositis is characterized by an insidious and multifactorial inflammatory process, which is often caused by hematogenous pathogen. Predisposing risk factors include immunodeficiency, diabetes, malignancy, or trauma. The spectrum of clinical presentation depends on disease severity, typically presented by fever and hip pain. We hereby present a case with extensive pyomyositis secondary to chronic paronychia infection.

PATIENT CONCERNS

A 14-year-old immunocompetent male presented with fever and hip pain. The patient was initially surveyed for common infectious etiologies prior to the presentation of acute limping, which led to image confirmation of extensive pyomyositis.

DIAGNOSIS

The patient presented with acute pain in the right hip accompanied by headache, myalgia of the right leg, and intermittent fever for a week. Physical examination disclosed limping gait, limited range of motion marked by restricted right hip flexion and right knee extension, and chronic paronychia with a nail correction brace of the left hallux. Diagnosis of pyomyositis was confirmed by magnetic resonance image. Methicillin-resistant strains of Staphylococcus aureus was isolated from the patient's blood and urine cultures within 2 days of collection. The same strain was also isolated from the pus culture collected via sonography-guided aspiration.

INTERVENTIONS

Antibiotics treatment with oxacillin, teicoplanin, daptomycin, and fosfomycin were administered. Sonography-guided aspiration and computed tomography-guided pigtail drainage were arranged, along with nail extraction of his left hallux paronychia prior to discharge. Oral antibiotics fusidic acid was prescribed. Total antibiotics course of treatment was 4 weeks.

OUTCOMES

The patient gradually defervesced and was afebrile after drainage. Followed limb doppler sonography showed regression of the abscess at his right lower limb. Gait and range of motion gradually recovered without sequelae.

LESSONS

Ambulation and quality of life are greatly affected by the inflammatory process of pyomyositis. Detailed evaluation of predisposing factors should be done, even in immunocompetent individuals. Timely diagnosis is vital to successful treatment.

Primary Pyomyositis in Children is No More a Rare Condition: Presentation of 2 Clinical Cases

Primary pyomyositis is a bacterial muscle infection which may lead to abscess formation and severe complications. Although this condition has long been considered "tropical" and rare, mostly affecting immunocompromised patients, cases of pyomyositis have recently raised significantly among healthy children in temperate climates. With these 2 cases we highlight the importance of an early recognition of this condition, allowing an immediate treatment and reducing complications.

Utility of Inflammatory Markers in Hospitalized Children With Skin Erythema

BACKGROUND

There is overlap in the clinical presentations of superficial skin infections (eg, cellulitis) and deeper infections (eg, osteomyelitis). Inflammatory markers are frequently obtained in hospitalized patients with cellulitis. However, it is unknown whether inflammatory markers discriminate between superficial and deeper infections.

METHODS

We performed a retrospective review of children hospitalized with erythema on the skin and diagnoses of cellulitis, bursitis, myositis, osteomyelitis, and/or tenosynovitis. Patients were grouped into superficial infection (cellulitis and bursitis) and deeper infection (myositis, tenosynovitis, osteomyelitis). We compared C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values between the two groups and constructed receiver operating characteristic curves to determine optimal cutoff values.

RESULTS

Among 168 children hospitalized with skin erythema, 122 patients had superficial and 46 patients had deeper infections. Mean CRP and ESR were significantly higher in patients with deeper infections (CRP: 8.3 [±9.6] mg/dL versus 2.8 [±3.5] mg/dL; P < .001; ESR: 48.3 [±28.6] mm/h versus 21.8 [±16.0] mm/h; P < .001). Neither WBC nor fever was significantly different between groups. CRP ≥2 mg/dL and ESR ≥30 mm/h were associated with deeper infections (CRP: odds ratio: 4.77; 95% confidence interval: 2.24-10.15; ESR: odds ratio: 7.93; 95% confidence interval: 3.46-17.67). When CRP and ESR were below these cutoffs, the negative predictive value was 89%.

CONCLUSIONS

Among patients presenting with skin erythema, CRP ≥2 mg/dL and ESR ≥30 mm/hr were significantly associated with deeper infection, whereas values below these cutoffs were reassuring against deeper infection. Future study of inflammatory markers in skin and soft tissue infections may help develop tailored testing strategies.

Etiology, Characteristics, and Outcomes of Community-Onset Pyomyositis in Korea: A Multicenter Study

Background

Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate.

Materials and Methods

We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with community-acquired (CA) and healthcare-associated (HCA) PM.

Results

One hundred eleven organisms were isolated from 96 (68.6%) patients with PM. Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S. aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01).

Conclusion

Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Rhizopus Infection in a Preterm Infant: A Novel Use of Posaconazole

Posaconazole is a triazole antifungal with activity against Rhizopus, but data on its use and pharmacokinetics in preterm infants are scarce. In this case, a 24 4/7-week neonate's Rhizopus infection is successfully treated with debridement and combination antifungal therapy with amphotericin B, micafungin and enteral posaconazole. This is the first reported posaconazole use in a preterm neonate with Rhizopus.

Pyomyositis in the United States 2002-2014

OBJECTIVES

Primary pyomyositis is a bacterial infection of skeletal muscle first recognized in tropical regions of the world but needing characterization in temperate climates.

METHODS

This population-based study used the Healthcare Utilization Project/Nationwide Inpatient Sample database to characterize the trends of pyomyositis admissions in the United States from 2002-2014 using ICD-9 diagnostic codes.

RESULTS

We found a concerning more than three-fold increase in the incident pyomyositis admissions over our study period. The median length of stay was over twice as long compared to other hospitalized patients. Patients with pyomyositis were younger and more likely to be male and Black. There were more cases in the West and South compared to Midwest and Northeast. Age-adjusted odds ratios revealed significant association of pyomyositis with HIV, types 1 and 2 diabetes mellitus, hematologic malignancy, organ transplant, malnutrition, chronic kidney disease, obesity, and rheumatoid arthritis. The most commonly identified bacterial diagnosis was Staphylococcus aureus. Pseudomonas species were the most commonly identified gram-negative bacteria.

CONCLUSION

This nationwide review of pyomyositis in the United States suggests a concerning increase in incidence and provides information on the trends, demographics, risk factors, and causative organisms for pyomyositis in the United States.

Multifocal Οsteomyelitis Localization after Pyomyositis in Children: Importance of Timely Response

Pyomyositis is a rare bacterial infection that used to prevail in tropical areas for the past century. Nowadays though, more and more cases are reported in high-temperature climate areas. Diagnosis is often delayed due to the variance in clinical presentation, the challenging nature of physical examination of a child, and lack of specific laboratory investigating tools. When the diagnosis is delayed, the outcome may be unpredictable. Multifocal localization through hematogenous or direct spread that may affect the skeletal bone tissue is common. Timely diagnosis and response is a race against septic shock.

We present a case series of seven children diagnosed with pyomyositis due to Staphylococcus aureus. High or less clinical suspicion has obviously affected the final outcome since two patients who were not treated in time were subjected to a life-threatening hazard. Five patients who were diagnosed and treated within the first three days after initiation of their symptoms had a predictable and good outcome without complications.

Panton-Valentine leucocidin is the key determinant of Staphylococcus aureus pyomyositis in a bacterial GWAS

Pyomyositis is a severe bacterial infection of skeletal muscle, commonly affecting children in tropical regions, predominantly caused by Staphylococcus aureus. To understand the contribution of bacterial genomic factors to pyomyositis, we conducted a genome-wide association study of S. aureus cultured from 101 children with pyomyositis and 417 children with asymptomatic nasal carriage attending the Angkor Hospital for Children, Cambodia. We found a strong relationship between bacterial genetic variation and pyomyositis, with estimated heritability 63.8% (95% CI 49.2–78.4%). The presence of the Panton–Valentine leucocidin (PVL) locus increased the odds of pyomyositis 130-fold (p=10^-17.9). The signal of association mapped both to the PVL-coding sequence and to the sequence immediately upstream. Together these regions explained over 99.9% of heritability (95% CI 93.5–100%). Our results establish staphylococcal pyomyositis, like tetanus and diphtheria, as critically dependent on a single toxin and demonstrate the potential for association studies to identify specific bacterial genes promoting severe human disease.

Certain bacteria that normally live on the skin or in the nose without causing problems can sometimes lead to diseases elsewhere in the body. For example, the bacterium Staphylococcus aureus can cause blood infections or a severe and painful infection of the muscle called pyomyositis, which is very common in children who live in the tropics.

Scientists believe that pyomyositis happens when S. aureus bacteria in the blood stream infect the muscles. Some strains of this bacteria are more likely to cause such infections, but why is unclear. One potential cause is a toxin produced by some S. aureus bacteria called Panton-Valentine leucocidin (PVL). So far, studies looking at whether PVL-producing bacteria are more likely to cause pyomyositis have had conflicting results.

Now, Young et al. show that the gene for PVL is always present in S. aureus strains that cause pyomyosistis in Cambodian children, but is rarely found in S. aureus taken from the noses of their healthy counterparts. In the experiments, bacteria were collected from 101 children with pyomyositis and from the noses of 417 healthy children at the Angkor Hospital for Children in Cambodia over a 5-year period. The DNA in these bacteria were compared using very sensitive genetic techniques. The comparisons showed having the gene for PVL increased the odds of having pyomyositis 130-fold, showing that this one toxin likely accounts for much of the risk of developing this disease.

If more studies confirm the link between PVL and pyomyositis, developing vaccines that block the gene for PVL might be one way to protect children in the tropics from developing this infection. Treating children with pyomyositis with antibiotics that reduce the production of the PVL toxin may also be helpful.

Group A Streptococcal Pyomyositis in a Previously Healthy Six-year-old Girl

A six-year-old previously healthy girl was seen in an outpatient pediatric clinic in the western United States for thigh pain. The pain was accompanied by an initial fever and was most severe after periods of prolonged rest. During the evaluation, her exam rapidly progressed with severe episodic pain and tenderness of the right anteromedial thigh. Magnetic resonance imaging (MRI) demonstrated signal enhancement at the insertion of the right obturator externus muscle. Blood culture was positive for Group A Streptococcus. She was diagnosed with pyomyositis of the right obturator externus and was successfully treated with antimicrobials. This case demonstrates a rare case of streptococcal pyomyosits, in a temperate climate, without known predisposing factor or injury. We review the epidemiology of streptococcal pyomyositis in temperate climates and discuss the presentation of pyomyositis in children.

Panton-Valentine Leukocidin Producing Staphylococcus Aureus Facial Pyomyositis Causing Partial Cavernous Sinus Thrombosis

We present a case of subtotal cavernous sinus thrombosis secondary to Panton-Valentine leukocidin-associated Staphylococcus aureus pyomyositis of the muscles of mastication in a previously healthy child, who was successfully managed with no residual disease. He was found to have a factor V Leiden heterozygous mutation. We highlight the propensity of Panton-Valentine leukocidin Staphylococcus aureus to induce venous thrombosis at any site but with potential for more severe consequences in the head. We highlight pyomyositis as a differential for periorbital cellulitis and discuss the significance of the factor V Leiden mutation.