Point-of-care ultrasound in diagnosing pyomyositis: a report of three cases

Abstract

Background: Pyomyositis is a bacterial infection of skeletal muscle that often results in deep intramuscular abscesses. The absence of external dermatologic manifestations in the early stages of pyomyositis makes this a challenging diagnosis. In addition, physical examination findings can be difficult to distinguish from more common processes, such as soft-tissue cellulitis. Clinicians can fail to diagnose this serious disease in a timely manner, resulting in delayed treatment and potential clinical deterioration from sepsis. Although advanced imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI) provide excellent detail, ultrasound (US) can also be used to detect this disease. US can be performed expeditiously at the bedside and is less expensive than CT or MRI. It allows the clinician to examine the deeper tissue planes of muscle, in which purulent fluid collections will develop as pyomyositis advances.

Case report: Three patients presenting with leg pain were evaluated with point-of-care (POC) US and diagnosed with pyomyositis. The early diagnosis of this condition prompted rapid treatment with administration of appropriate antibiotics and involvement of orthopedic surgery. Aspiration of fluid allowed for detailed fluid analysis and bacterial cultures. Additional diagnostic imaging was performed, confirming the initial US diagnosis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: POC US can be helpful in identifying and further delineating intramuscular abscesses and can subsequently lead to expedited and appropriate care in patients who present with extremity pain, but lack significant dermatologic changes.

Keywords: intramuscular abscess; muscle infections; point-of-care ultrasound; pyomyositis.