Pyomyositis of the pectineus muscle in an adolescent male

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.

The Utility of Musculoskeletal Ultrasonography in Diagnosing Pyomyositis: A Comparison With Surgically and Conservatively Treated Cases

Objective:

The study aimed to determine the accuracy of sonography in diagnosing pyomyositis.

Methods:

A retrospective review of pyomyositis cases in a government hospital between January 1, 2016 and June 30, 2019 was done. All cases underwent a sonogram for the indication of pyomyositis. Positive purulence for surgical cases and improved laboratory parameters for conservative cases were confirmatory for pyomyositis. Comparison with sonographic results using a 2 × 2 contingency table was done to determine sensitivity and specificity.

Results:

A total of 122 cases were included. The sonographic results corresponded with 95% of surgical cases and 89% of conservative cases. A lack of false and true negatives for surgical cases resulted in a sensitivity of 100% (95% confidence interval [CI] = 93%–100%) and a specificity of 0% (95% CI = 0%–71%). In conservative cases, sonography had a sensitivity of 92% (95% CI = 82%–97%) and a specificity of 0% (95% CI = 0%–84%) due to a lack of true negatives.

Conclusion:

Sonography is not limited to primarily as a screening tool but a capable diagnostic imaging choice for pyomyositis, particularly in low-resource settings. The results show the strength of sonography, particularly in the suppurative stage of pyomyositis. [Box: see text]

Purulent infectious myositis (formerly tropical pyomyositis)

Purulent infectious myositis (PIM), formerly known as tropical pyomyositis, is a pyogenic infection of skeletal muscles. Staphylococcus aureus, a normal human skin inhabitant, is the main pathogen involved, but multiple other microorganisms have been implicated. Although usually a progressive febrile disease with pain in the affected muscle(s), severe, life-threatening forms have been described, especially in immunosuppressed patients and children. PIM may elude early diagnosis given the lack of overlying skin changes. Hence, high index of suspicion followed by imaging modalities (ultrasonography when superficial and computed tomography or magnetic resonance imaging with contrast when deep) help confirm the diagnosis. Treatment requires combination of percutaneous or open surgical drainage along with antimicrobial therapy guided by culture results. The rising incidence of cases due to methicillin-resistant Staphylococcus aureus (MRSA) strains, makes the inclusion of vancomycin be recommended. This paper reviews PIM highlighting its global distribution, causative agents, predisposing factors, management, and potential complications.