Arthrocentesis in the Emergency Department

Abstract

Arthrocentesis in the Emergency Department Abstract. Acute joint swelling is a common presentation to the emergency department. Although routine investigations like clinical exam, labs and eventually x-ray are usually obtained, definitive diagnosis must be established since timely recognition of septic arthritis in particular is crucial. Definitive diagnosis is achieved by performing an arthrocentesis of the affected joint. While arthrocentesis of larger joints and large effusions (e. g. knee) are relatively easy to perform using the landmark-technique, smaller and less accessible joints (shoulder, elbow, hip) are more difficult to access and it is therefore recommended to use ultrasound guidance. Compared with the landmark-technique, ultrasound-guided arthrocentesis is more successful and less painful. Synovial fluid should be analyzed for cell count with differential, crystals as well as for microbiological analysis such as Gram-stain and culture. Once the diagnosis of septic arthritis has been established, irrigation of the joint should be performed by orthopedic surgery. Antibiotic therapy should be withheld until the sampling of synovial fluid has been completed. After exclusion of septic arthritis, acute arthritis due to crystal arthropathy (CPPD or gout) is treated with either glucocorticoid-infiltration of the joint or with nonsteroidal anti-inflammatory drugs. In this article, the different technical aspects of arthrocentesis are discussed, including asepsis, landmark- and ultrasound-guided access, preanalytics and interpretation of the laboratory results.