Metástasis séptica en quiste de Baker como complicación tras radiofrecuencia de cornetes

Abstract

Introduction: A Baker’s cyst (BC) or popliteal cyst is a distention of the gastrocnemius–semimembranous bursa of the knee. It is usually asymptomatic and associated to known knee pathology. The incidence of BC is between 5% and 38% and increases with aging. Its most frequent complication is rupture. Infection of a BC is an uncommon complication usually associated with septic arthritis. Ultrasound examination is appropriate for identifying and measuring the cyst and MRI is the gold-standard imaging study to confirm the presence and the complications of a BC. Cyst puncture under ultrasound guidance decompresses the cyst and allows to obtain material for cultures. The most common organism isolated is S. aureus. Infected BC requires prolonged antibiotic therapy because of the risk of septic arthritis. Method: A 64-year-old man presented with chronic nasal obstruction secondary to inferior turbinate hypertrophy. His personal history includes arterial hypertension, hypercholesterolemia and right knee arthroscopic surgery for meniscus tears 15 years ago. Radiofrequency turbinoplasty was performed without incident. Nasal packing was not necessary and topical antibiotic ointment (bacitracin and neomycin) was prescribed. Two days later, the patient presented with sudden right popliteal pain asociated with swelling, erythema and fever. An ultrasound was performed showing a complicated Baker's cyst (7x3 cm). Drainage of purulent material was performed and cultures were positive for methicillin-sensitive S. aureus (MSSA). MSSA bacteremia after turbinoplasty was suspected, so echocardiogram was requested to rule out infective endocarditis, but no lesions were observed. Given the associated risk of septic arthritis, treatment with intravenous cloxacillin 12mg/24h for 2 weeks and then levofloxacin 500mg/24h for 4 weeks was prescribed. The patient evolved favorably and is currently asymptomatic. Conclusions: Infected Baker's cyst incidence is very low with few reports in the literature. Possible sources of entry of pathogens should be studied, in our case, bacteriemia was most likely secondary to radiofrequency turbinoplasty.