Virginia Via Research Day Book 2026

Medical Student Research Case Reports

32 INFECTIOUS NECROTIZING MYOSITIS: A CASE ILLUSTRATING THE NEED FOR HIGH CLINICAL SUSPICION

Ashley Borseth, OMS-III, Sean Thuesen, DO, Dr. Tyler Willson, MD Corresponding author: aborseth@vcom.eduu VCOM-Virginia, Blacksburg, Virginia Virginia Tech Carilion Clinic School of Medicine, Roanoke, Virginia Context: Necrotizing myositis is a rare, life threatening condition often derived from autoimmune or infectious etiologies. Early diagnosis is essential to provide proper intervention. Report of Case: Here, we report a 64-year-old female with diabetes, hypertension, hyperlipidemia, and chronic kidney disease who presented with presumed worsening cellulitis following a recent camping trip. The patient was afebrile, had a heart rate of 98 beats per minute, and was hypertensive at 153/66 mmHg. Physical exam revealed erythema of the left thigh without palpable crepitus. Initial laboratory work up revealed a leukocytosis of 27.7 K/uL with elevated inflammatory markers, which included a c-reactive protein of 22.73 mg/dL and an erythrocyte sedimentation rate of 129 mm/HR. Venous lactate was elevated at 2.3 mmol/L. Due to the patient’s reported history of contrast-induced nephropathy, non contrast computed tomography (CT) of the left thigh was obtained and found nonspecific circumferential soft tissue thickening without fascial fluid collection. General surgery was consulted, and broad-spectrum antibiotics were initiated due to concern for necrotizing fasciitis based on their initial evaluation and an elevated LRINEC score of 9. After careful monitoring over

a couple days, the surgical team thought necrotizing fasciitis was less likely given the absence of rapid skin changes and disproportionate pain, and did not elect to proceed with surgical intervention. Despite antibiotic treatment, the patient’s white blood cell count remained elevated, prompting a non-contrast magnetic resonance imaging (MRI) scan, which revealed evidence of dermatomyositis. Antibiotics were discontinued, and muscle biopsy was obtained. The patient was discharged home with a presumed diagnosis of an autoimmune necrotizing process. At follow-up, the patient presented with worsening swelling of the left thigh, and physical exam identified fluctuance and induration. Clinical presentation during the second admission was consistent with a developing abscess rather than an autoimmune process previously suggested by muscle biopsy. A repeat MRI confirmed a new 25-cm complex abscess of the thigh that was treated with surgical debridement and antibiotics. Comments: A review of literature was conducted to compare presentation, diagnostics, and management of necrotizing myositis. Consistent with established reports of both autoimmune and infectious etiologies,

this case reflects the pattern of systemic inflammation and nonspecific early findings. The unusual discrepancy between muscle biopsy and the patient’s clinical presentation delayed appropriate management. The diagnosis of an autoimmune necrotizing process, without clinical worsening, would traditionally lead to corticosteroid therapy, whereas an infectious etiology would require urgent surgical debridement and antibiotics. In this case, suboptimal imaging and limited sensitivity of LRINEC scoring contributed to postponement of correct treatment. The patient’s clinical trajectory also suggests that early infectious myositis may have contributed to the subsequent formation of the complex thigh abscess. Initial imaging was nonspecific, though the muscle inflammation may have been the origin for deeper infection later revealed on MRI. Conclusion: This case is notable for its uncommon discordance between a muscle biopsy revealing an autoimmune process, followed by the rapid emergence of abscess formation. Here, we highlight the diagnostic challenges when imaging and clinical evolution do not align in a case of infectious myositis.

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70 Edward Via College of Osteopathic Medicine (VCOM)