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

A case of extraocular muscle pyomyositis in an elderly patient with diabetes mellitus

Pyomyositis is a bacterial infection of skeletal muscle leading to abscess formation. Younger males are predominantly involved, but pyomyositis may occur in all ages and sexes. Underlying systemic disease or accompanying immunocompromised states may increase the risk of pyomyositis. This is a report of a 72-year-old, male, with uncontrolled diabetes mellitus, presenting initially as a case of orbital cellulitis. Magnetic resonance imaging confirmed the presence of an abscess in the left lateral rectus. Antibiotic therapy was promptly initiated, and drainage of the abscess was performed via a transconjunctival approach. Pyomyositis resolved post-surgery and medical therapy. Residual exotropia was noted at the eighth month of follow-up necessitating subsequent strabismus surgery. Nine months post-treatment, left lateral rectus pyomyositis did not recur.

Tropical pyomyositis

Tropical pyomyositis is a serious infectious disease characterised by the formation of abscesses in the skeletal muscles and is primarily caused by Staphylococcus aureus, with an increasing incidence in non-tropical regions. The disease primarily affects men and young adults, often following minor trauma, with an increasing incidence in immunocompromised individuals. Immunocompromised hosts are more likely to be affected by Gram-negative organisms, Mycobacterium tuberculosis, opportunistic infections such as fungal pathogens, non-tuberculous mycobacteria, and Nocardia species. Diagnosis is complicated by non-specific symptoms and the low yield of blood cultures, so imaging studies such as Magnetic Resonance Imaging (MRI) are required for accurate identification. Treatment focuses on controlling the source through drainage, tailored antibiotic therapy, and supportive care, especially in patients with complications such as multi-organ dysfunction. Given the complex clinical manifestations, heightened awareness and a collaborative approach to education and resource provision are critical to improving outcomes in patients with tropical pyomyositis.

Dysphagia and Trismus After Tooth Extraction : Clinical Conondrum

Clinicians should consider disorders of masticatory muscle including lateral pterygoid muscle as a differential diagnosis in patients presenting with dysphagia and trismus after tooth extraction.

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.

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.

Subscapularis pyomyositis, a rare cause of shoulder pain, in a patient without apparent risk factors: A case report

INTRODUCTION

Pyomyositis, previously tropical, now seen more in temperate zones, particularly in those with HIV, cancer, or diabetes. Even healthy individuals, like athletes, can get it post-exercise or minor injuries. Our patient, in a desert-like area, adds an interesting aspect. Diagnosing is challenging due to deep tissue occurrence and subtle symptoms, leading to delayed detection and higher risks of morbidity.

PRESENTATION OF CASE

A 45-year-old female patient presented with acute left shoulder pain and functional impairment, exacerbated by movement. Clinical examination revealed tenderness upon deep palpation in the left upper posterior thoracic region and restricted range of motion of the affected shoulder.

DISCUSSION

Initial assessments at medical facilities suggested musculoskeletal strain and lower cervical disc prolapse despite normal X-ray results. MRI scans confirmed a developing abscess in the left subscapularis muscle, with intraoperative findings revealing extensive purulent fluid and necrotic tissue. Four surgeries drained the abscess and treated fat necrosis, with tailored antibiotics administered. Subsequent arthroscopy showed fibrous tissue, swelling, and inflammation. At the 3-month check-up, she had fully recovered, experiencing no pain or complications, and had almost regained full range of motion.

CONCLUSION

Shoulder pyomyositis presents diagnostic challenges, causing delayed treatment. This case highlights the importance of considering pyomyositis in severe shoulder pain cases, even without typical risk factors or inconclusive X-rays. Timely recognition, surgical drainage, tailored antibiotics, and physical therapy are crucial. An interdisciplinary approach with orthopaedic surgery, infectious disease specialists, radiology, and physical therapy is vital for comprehensive management, improving outcomes, and reducing complications.

Dry and liquid formulations of IBT-V02, a novel multi-component toxoid vaccine, are effective against Staphylococcus aureus isolates from low-to-middle income countries

Staphylococcus aureus is the leading cause of skin and soft tissue infections (SSTIs) in the U.S. as well as more serious invasive diseases, including bacteremia, sepsis, endocarditis, surgical site infections, osteomyelitis, and pneumonia. These infections are exacerbated by the emergence of antibiotic-resistant clinical isolates such as methicillin-resistant S. aureus (MRSA), highlighting the need for alternatives to antibiotics to treat bacterial infections. We have previously developed a multi-component toxoid vaccine (IBT-V02) in a liquid formulation with efficacy against multiple strains of Staphylococcus aureus prevalent in the industrialized world. However, liquid vaccine formulations are not compatible with the paucity of cold chain storage infrastructure in many low-to-middle income countries (LMICs). Furthermore, whether our IBT-V02 vaccine formulations are protective against S. aureus isolates from LMICs is unknown. To overcome these limitations, we developed lyophilized and spray freeze-dried formulations of IBT-V02 vaccine and demonstrated that both formulations had comparable biophysical attributes as the liquid formulation, including similar levels of toxin neutralizing antibodies and protective efficacy against MRSA infections in murine and rabbit models. To enhance the relevancy of our findings, we then performed a multi-dimensional screen of 83 S. aureus clinical isolates from LMICs (e.g., Democratic Republic of Congo, Palestine, and Cambodia) to rationally down-select strains to test in our in vivo models based on broad expression of IBT-V02 targets (i.e., pore-forming toxins and superantigens). IBT-V02 polyclonal antisera effectively neutralized toxins produced by the S. aureus clinical isolates from LMICs. Notably, the lyophilized IBT-V02 formulation exhibited significant in vivo efficacy in various preclinical infection models against the S. aureus clinical isolates from LMICs, which was comparable to our liquid formulation. Collectively, our findings suggested that lyophilization is an effective alternative to liquid vaccine formulations of our IBT-V02 vaccine against S. aureus infections, which has important implications for protection from S. aureus isolates from LMICs.

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.

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.

Pyomyositis of the Biceps Brachii in a Young Adult Male

Pyomyositis is a skeletal muscle infection mainly found in tropical regions. It commonly affects larger muscles, especially those of the hips. MRI tends to be the gold standard for diagnosis. Staphylococcus aureus remains the predominant causal organism in most cases of pyomyositis. Immunocompromised patients are more likely to be susceptible to this infection. In our case, an immunocompetent 27-year-old male in rural southwest Virginia was found to have a large abscess in his upper arm. Contrast-enhanced CT scan was acquired prior to drainage, leading to the diagnosis of pyomyositis. Empiric treatment with IV vancomycin 1 g q 24 hours and piperacillin/tazobactam 3.375 mg q 8 hours, prompt incision and drainage, and negative pressure wound VAC led to a complete resolution of the infection.

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.

Physiotherapeutic Protocol and ZnO Nanoparticles: A Combined Novel Treatment Program against Bacterial Pyomyositis

Myositis tropicans or pyomyositis is a muscle inflammation resulting from a bacterial infection of skeletal muscle (commonly caused by Staphylococcus aureus) that usually leads to hematogenous muscle seeding. The present study was designed to estimate the role of ZnO-NPs and a physiotherapeutic program in the management of induced biceps femoris atrophy in rats through histological, biochemical, and radiological examinations at different time intervals. At the beginning, several bacterial strains were evaluated through a proteolytic enzyme activity assay and the highest activity was recorded with the Staphylococcus aureus strain. ZnO-NPs were synthesized with the arc discharge method with an average size of 19.4 nm. The antibacterial activity of ZnO-NPs was investigated and it was revealed that the prepared ZnO-NPs showed a minimum inhibitory concentration of 8 µg/mL against the tested bacterium. The cytotoxicity of the prepared ZnO-NPs was tested in C2C12 myoblast cells, and it was elaborated that CC50 was 344.16 µg/mL. Biceps femoris pyomyositis was induced with a potent strain (Staphylococcus aureus); then, a physiotherapeutic program combined with the prepared ZnO-NPs treatment protocol was applied and evaluated. The combined program claimed antibacterial properties, preventing muscle atrophy, and resulted in the most comparable value of muscle mass.

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.