Emergency department diagnosis of a quadriceps intramuscular loculated abscess/pyomyositis using dynamic compression bedside ultrasonography.

INTRODUCTION: A 73-year-old man with a past medical history of myelodysplastic syndrome and recent chemotherapy presented to the emergency department with a 1-week history of progressively increasing left thigh pain and swelling. His physical examination revealed left anterolateral diffuse thigh swelling with no erythema or warmth to palpation. The anterolateral quadriceps was markedly tender to palpation. Emergency department bedside dynamic compression ultrasonography that was performed on the left anterolateral thigh revealed a quadriceps intramuscular abscess with loculated yet movable pus. CONCLUSION: Bedside dynamic compression ultrasonography can assist the emergency or critical care physician in the diagnosis of quadriceps intramuscular abscess or pyomyositis.