Piriformis Pyomyositis Presenting as Migratory Hip to Knee Pain: A Case Report

CASE The authors report a case of piriformis pyomyositis in a teenage female patient with fever and left hip pain. Her pain migrated to the knee with concurrent near resolution of hip pain. Imaging revealed an abscess in the left piriformis with pus tracking along the sciatic nerve sheath. This was complicated by internal iliac vein thrombosis and an embolus to the lung. Open drainage was performed, followed by outpatient intravenous cloxacillin and oral warfarin, with complete resolution of symptoms. CONCLUSION Piriformis pyomyositis is a rare condition with varying presentations. The threshold for suspicion should be low even in healthy young individuals.