Chylous joint effusion: A rare entity that mimics septic arthritis

Abstract

Chylous joint effusions are infrequent conditions characterized by their macroscopic milky appearance. Their detection warrants a work-up to rule out an extensive list of triggers. Also to consider is that at onset they may mimic infectious arthritis. This report describes a young man complaining of post-trauma knee pain and swelling. Both the macroscopic aspect and the biochemical composition of the synovial fluid were consistent with a chylous effusion. It contained large amounts of neutral lipids, and mostly triglycerides. We could exclude infections, as well as other possible causes of the episode and concluded that it had been precipitated by joint injury. Trauma has been formerly identified as causative agent of chylous effusions in other four cases. We outline that the real challenge in these conditions is to make a correct diagnostic approach. Otherwise, they are self-limited and only symptomatic care is needed.