Tropical pyomyositis: an update

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.

Bacterial pyomyositis of the extraocular muscles: case report and systematic review

OBJECTIVE

To describe the manifestations and treatment of extraocular muscle (EOM) bacterial pyomyositis.

DESIGN

A systematic review following PRISMA guidelines and a case report.

METHODS

PubMed and MEDLINE databases were searched for case reports and case series of EOM pyomyositis using the term "extraocular muscle" combined "pyomyositis" and "abscess". Patients were included as bacterial pyomyositis of the EOMs when there was a response to antibiotics alone or if a biopsy was consistent with the diagnosis. Patients were excluded when pyomyositis did not involve the EOMs or when diagnostic tests or treatment were not in keeping with the diagnosis of bacterial pyomyositis. An additional patient with bacterial myositis of the EOMs, treated locally, was added to the cases identified in the systematic review. Cases were grouped for analysis.

RESULTS

There are 15 published cases of EOM bacterial pyomyositis including the one reported in this paper. Bacterial pyomyositis of the EOMs typically affects young males and is caused by Staphylococcus species. Most patients present with ophthalmoplegia (12/15; 80%), periocular edema (11/15; 73.3%), decreased vision (9/15; 60%) and proptosis (7/15; 46.7%). Treatment involves antibiotics alone or in combination with surgical drainage.

CONCLUSIONS

Bacterial pyomyositis of the EOM presents with the same signs as orbital cellulitis. Radiographic imaging identifies a hypodense lesion with peripheral ring enhancement within the EOM. An approach to cystoid lesions of the EOMs is helpful in reaching the diagnosis. Cases can be resolved with antibiotics aimed at treating Staphylococcus, and surgical drainage may be required.

Tuberculous pyomyositis presenting as septic arthritis and multiple site pyomyositis

Primary tropical pyomyositis, commonly caused by Staphylococcus aureus, is characterised by suppuration in skeletal muscles, which manifests as single or multiple abscesses. Another rare causative organism is Mycobacterium tuberculosis in endemic areas. Here, we report a case of primary tuberculous pyomyositis presenting as septic arthritis of the right knee and multiple site pyomyositis of the right thigh and chest wall. A tuberculous aetiology was overlooked at first, which resulted in a diagnostic delay. The patient was initially diagnosed, using ultrasonography, MRI and an absence of systemic symptoms of tuberculosis, with bacterial pyomyositis and treated with broad-spectrum antibiotics. However, further investigations performed on knee joint aspirate yielded negative cultures and a positive cartridge-based nucleic acid amplification test, which, along with a non-resolution of his symptoms, suggested a primary tuberculous pyomyositis. He was successfully managed with incision and drainage of the lesions and completion of anti-tubercular therapy.

Spontaneous widespread muscle hematoma complicated by pyomyositis in a case of dengue hemorrhagic fever: a case report from Nepal

Introduction and importance

Most dengue infections are asymptomatic, and some of them develop haemorrhagic manifestations with or without shock. However, dengue can sometimes present with very rare complications like pyomyositis.

Case presentation

A healthy 27-year-old male, presented with a 2-day fever, confirmed to be dengue through a positive non-structural protein 1 test. Despite initial symptomatic management, his condition worsened and he was hospitalized. Leucocyte and platelet counts dropped to the lowest value on the seventh day of illness, followed by the gradual development of chest pain, persistent fever, and severe limb pain. Radiographic evaluation revealed pleural effusion, and multiple intramuscular haematomas complicated by pyomyositis. Pleural effusion resolved on its own. Pyomyositis resolved with 6 weeks of appropriate antibiotics and aspiration of pus.

Clinical discussion

Dengue infection, caused by a dengue virus transmitted through Aedes mosquitoes, is a significant public health concern in many parts of the world. Dengue haemorrhagic fever is a severe form of dengue infection characterized by vascular leakage, thrombocytopenia, and bleeding manifestations. Although musculoskeletal manifestations are common in dengue fever, the occurrence of multiple muscle haematomas and pyomyositis as complications of Dengue haemorrhagic fever is rare. Drainage or aspiration of pus combined with the antibiotics according to the pus culture and sensitivity report is the management strategy.

Conclusion

Prolonged fever with severe musculoskeletal pain and focal tenderness on examination in a dengue patient, warrant radiographic testing (ultrasonography or MRI) considering the differentials of haematoma, myositis, or pyomyositis.

Primary bacterial intercostal pyomyositis diagnosis: A case report

RATIONALE

Pyomyositis is a microbial infection of the muscles and contributes to local abscess formation. Staphylococcus aureus frequently causes pyomyositis; however, transient bacteremia hinders positive blood cultures and needle aspiration does not yield pus, especially at the early disease stage. Therefore, identifying the pathogen is challenging, even if bacterial pyomyositis is suspected. Herein, we report a case of primary pyomyositis in an immunocompetent individual, with the identification of S aureus by repeated blood cultures.

PATIENT CONCERNS

A 21-year-old healthy man presented with fever and pain from the left chest to the shoulder during motion. Physical examination revealed tenderness in the left chest wall that was focused on the subclavicular area. Ultrasonography showed soft tissue thickening around the intercostal muscles, and magnetic resonance imaging with short-tau inversion recovery showed hyperintensity at the same site. Oral nonsteroidal anti-inflammatory drugs for suspected virus-induced epidemic myalgia did not improve the patient's symptoms. Repeated blood cultures on days 0 and 8 were sterile. In contrast, inflammation of the soft tissue around the intercostal muscle was extended on ultrasonography.

DIAGNOSES

The blood culture on day 15 was positive, revealing methicillin-susceptible S aureus JARB-OU2579 isolates, and the patient was treated with intravenous cefazolin.

INTERVENTIONS

Computed tomography-guided needle aspiration from the soft tissue around the intercostal muscle without abscess formation was performed on day 17, and the culture revealed the same clone of S aureus.

OUTCOMES

The patient was diagnosed with S aureus-induced primary intercostal pyomyositis and was successfully treated with intravenous cefazolin for 2 weeks followed by oral cephalexin for 6 weeks.

LESSONS

The pyomyositis-causing pathogen can be identified by repeated blood cultures even when pyomyositis is non-purulent but suspected based on physical examination, ultrasonography, and magnetic resonance imaging findings.

Rapidly-Progressing Pyomyositis After Chest Contusion in a Patient With Well-Controlled Diabetes Mellitus

Pyomyositis is an uncommon acute bacterial infection of the skeletal muscle. It is sometimes referred to as "tropical pyomyositis" because it has been primarily reported as an endemic disease in tropical regions. In temperate climates, it is mainly diagnosed in immunocompromised persons, such as those with human immunodeficiency virus infection, malignancy, diabetes, and various other medical conditions. Early diagnosis and appropriate antimicrobial therapy for pyomyositis are important, however, it is often missed in its early stage. Herein, we report the case of a patient with obesity and well-controlled diabetes in whom rapid onset pyomyositis developed in only 2 days after chest contusion and induced bacteremia in its early stage. He was successfully treated by antimicrobials without any drainage or surgical intervention. Even in patients with well-controlled diabetes or in healthy persons, pyomyositis should be considered for patients who present with fever and muscle swelling and pain, especially when they have obesity and a history of blunt trauma. It should also be noted that pyomyositis, mimicking muscle contusion or hematoma can appear very early after blunt muscle trauma. Prompt diagnosis and antimicrobial treatment for pyomyositis can lead to a favorable outcome, without surgical drainage.

Impaired muscle stem cell function and abnormal myogenesis in acquired myopathies

Skeletal muscle possesses a high plasticity and a remarkable regenerative capacity that relies mainly on muscle stem cells (MuSCs). Molecular and cellular components of the MuSC niche, such as immune cells, play key roles to coordinate MuSC function and to orchestrate muscle regeneration. An abnormal infiltration of immune cells and/or imbalance of pro- and anti-inflammatory cytokines could lead to MuSC dysfunctions that could have long lasting effects on muscle function. Different genetic variants were shown to cause muscular dystrophies that intrinsically compromise MuSC function and/or disturb their microenvironment leading to impaired muscle regeneration that contributes to disease progression. Alternatively, many acquired myopathies caused by comorbidities (e.g., cardiopulmonary or kidney diseases), chronic inflammation/infection, or side effects of different drugs can also perturb MuSC function and their microenvironment. The goal of this review is to comprehensively summarize the current knowledge on acquired myopathies and their impact on MuSC function. We further describe potential therapeutic strategies to restore MuSC regenerative capacity.

Gram negative pyomyositis: Two case reports and a review of the literature

Pyomyositis due to Gram negative bacteria is rare. Here we describe two cases in immunocompromised hosts. Both were bacteremic with a Gram-negative bacterium and had impaired immunity related to prolonged and ongoing chemotherapy for hematologic malignancies. Both eventually cleared the infection with a combination of local drainage and systemic antibiotics. This unusual diagnosis should be considered in an immunocompromised patient with muscle pain and fever.

Ultrasound-Guided Conservative Treatment of Pyomyositis Due to Metamizole-Induced Agranulocytosis

Metamizole-induced agranulocytosis is a rare adverse drug reaction with common infectious complications. In this context, pyomyositis of the extremities has not yet been described. Usually, pyomyositis is treated with a combination of antibiotics and surgical intervention. Sonography is described as diagnostic tool for pyomyositis but without defined concrete characteristics for follow-up. This case report describes a widespread pyomyositis due to a metamizole-induced agranulocytosis, which was treated conservatively, using sonography for surveillance.

A 6-Year Update on the Diversity of Methicillin-Resistant Staphylococcus aureus Clones in Africa: A Systematic Review

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of hospital-associated (HA) and community-associated (CA) infections globally. The multi-drug resistant nature of this pathogen and its capacity to cause outbreaks in hospital and community settings highlight the need for effective interventions, including its surveillance for prevention and control. This study provides an update on the clonal distribution of MRSA in Africa.

Methods

A systematic review was conducted by screening for eligible English, French, and Arabic articles from November 2014 to December 2020, using six electronic databases (PubMed, EBSCOhost, Web of Science, Scopus, African Journals Online, and Google Scholar). Data were retrieved and analyzed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines (registered at PROSPERO: CRD42021277238). Genotyping data was based primarily on multilocus sequence types (STs) and Staphylococcal Cassette Chromosome mec (SCCmec) types. We utilized the Phyloviz algorithm in the cluster analysis and categorization of the MRSA STs into various clonal complexes (CCs).

Results

We identified 65 studies and 26 publications from 16 of 54 (30%) African countries that provided sufficient genotyping data. MRSA with diverse staphylococcal protein A (spa) and SCCmec types in CC5 and CC8 were reported across the continent. The ST5-IV [2B] and ST8-IV [2B] were dominant clones in Angola and the Democratic Republic of Congo (DRC), respectively. Also, ST88-IV [2B] was widely distributed across the continent, particularly in three Portuguese-speaking countries (Angola, Cape Verde, and São Tomé and Príncipe). The ST80-IV [2B] was described in Algeria and Egypt, while the HA-ST239/ST241-III [3A] was only identified in Egypt, Ghana, Kenya, and South Africa. ST152-MRSA was documented in the DRC, Kenya, Nigeria, and South Africa. Panton-Valentine leukocidin (PVL)-positive MRSA was observed in several CCs across the continent. The median prevalence of PVL-positive MRSA was 33% (ranged from 0 to 77%; n = 15).

Conclusion

We observed an increase in the distribution of ST1, ST22, and ST152, but a decline of ST239/241 in Africa. Data on MRSA clones in Africa is still limited. There is a need to strengthen genomic surveillance capacity based on a "One-Health" strategy to prevent and control MRSA in Africa.

A case report: septic shock due to (tropical) pyomyositis and multiple metastatic embolisms caused by Panton Valentine Leukocidin-positive methicillin-sensitive staphylococcus aureus in a 12-year-old boy

CASE REPORT

A 12-year-old boy, of Congolese roots and without medical history, first presented to our Emergency Department 3 days after blunt trauma of the left ankle. The boy represented on two more occasions in the next 3 days due to ongoing pain. On the last occasion he presented with severe hypoglycaemia. He was diagnosed with severe septic shock, secondary to subperiosteal abscess formation / osteomyelitis of the ankle. The patient was transferred to the paediatric intensive care unit where appropriate medical care was provided, including broad-spectrum antibiotic therapy, high dose vasopressor / inotropic support, surgical debridement of abscesses and below-knee amputation.

PANTON VALENTINE LEUKOCIDIN TOXIN AND PYOMYOSITIS TROPICALIS

The causative organism was a methicillin-susceptible S. aureus, which upon further identification was a carrier of the PVL (Panton Valentine leukocidin) toxin. This pathogen is responsible for severe musculoskeletal infections. In children these infections are often associated with more severe clinical course requiring a higher need for surgical intervention and longer hospital stay.Tropical pyomyositis is a disease caused by Staphylococcus aureus, often seen in tropical countries, and classically presented with muscle abscesses. Young males between the ages of 10-40 years old are the most susceptible, and often present with a history of blunt trauma. Treatment generally requires a combination of an anti-staphylococcal agent, and an anti-toxic agent blocking bacterial protein-synthesis of PVL. Source control by surgical debridement also plays a major role in the treatment of PVL-infection. Despite agressive treatment, mortality still varies from 0.5% to 2%.

Severe thoracic pyomyositis in a patient with systemic lupus erythematosus

Pyomyositis may mimic deep vein thrombosis and be misdiagnosed in patients with systemic lupus erythematosus (SLE). We report here on patient with SLE with severe thoracic pyomyositis presented with right upper arm swelling and fever. The patient fully recovered after a serial surgical debridement and antibiotic therapy. Pyomyositis, as well as deep vein thrombosis, should be considered during the differential diagnosis of patients with SLE experiencing fever and unilateral limb oedema. CT and identification of causal pathogens are crucial in the diagnosis of pyomyositis. Early effective antibiotic treatment as well as surgical intervention can together bring about a better outcome.

Neglected tropical rheumatic diseases

The complexities of dealing with rheumatic diseases in tropical countries are diverse and likely due to limited health care infrastructure, lack of diagnostic and therapeutic facilities, impact of dominant prevailing diseases, and the challenges of differentiating from infectious and non-infectious disease mimics. Several tropical diseases present with musculoskeletal and rheumatic manifestations and often pose a diagnostic dilemma to rheumatologists. The diagnosis is often delayed or the disease is misdiagnosed, leading to poor patient outcomes. Endemic tropical diseases like tuberculosis and leprosy have myriad rheumatic presentations and remain important differentials to consider in patients with rheumatic manifestations. Infection with human immunodeficiency virus is a great masquerade and can mimic manifestations of multiple diseases. The role of viral infections in triggering and perpetuating autoimmunity is well known and chikungunya arthritis is a classic example of the same. This review highlights the rheumatic manifestations of tropical diseases and aims to create awareness among the caregivers. Key Points • It is crucial to be aware and identify infectious diseases presenting with rheumatic manifestations in the tropics. • Presentations akin to classic rheumatic syndromes such as rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus and vasculitis are common.

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.

Imaging review of normal anatomy and pathological conditions involving the popliteus

Popliteus is an integral component of the posterolateral corner of the knee. We review the anatomy and various pathologies affecting the popliteus.

Tropical pyomyositis in scrub typhus: a rare association

Tropical pyomyositis manifests as single or multiple abscesses inside skeletal muscles and it has a higher prevalence in immunocompromised patients. Scrub typhus, a zoonotic disease is caused by Orientia tsutsugamushi and the clinical manifestations range from simple febrile illness to organ threatening complications. Here, we present a rare case of an immunocompetent young man diagnosed as tropical pyomyositis in association with scrub typhus. Imaging of both thighs revealed multiple intramuscular abscesses. Blood and aspirated pus were culture negative. Patient was treated aggressively with parenteral antibiotics (linezolid, clindamycin and meropenem) and surgical debridement. But, fever did not subside and total leucocyte count remained persistently high. After serological confirmation of scrub typhus, the patient was put on oral doxycycline and he had a dramatic improvement within next few days. To the best of our knowledge, this is probably the first reported case of tropical pyomyositis in association with scrub typhus.

Septic emboli from pyomyositis

Pyomyositis commonly presents with fever, muscle pain and abscess formation involving deep soft-tissue compartments. Staphylococcus aureus is the main causative organism and diagnosis is usually established clinically, supported by imaging, but confirmation may be achieved by histopathological examination. Broad-spectrum antibiotic therapy and surgical debridement are the cornerstone of treatment. Its prognosis is good but, as in all soft-tissue infections, it depends on early intervention, directed antibiotics and, if indicated, prompt surgery. In this paper, we describe a case of pelvic pyomyositis complicated with bacteraemia and bilateral septic pulmonary emboli in a young man in Colombia.