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Cathryn Caton, MD, MS Medical University of South Carolina May 23, 2013. Arthrocentesis. Objectives. Define arthrocentesis Review reasons for procedure Review contraindications for procedure Describe procedural technique Review fluid analysis and related diagnoses. Definition.
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Cathryn Caton, MD, MS Medical University of South Carolina May 23, 2013 Arthrocentesis
Objectives • Define arthrocentesis • Review reasons for procedure • Review contraindications for procedure • Describe procedural technique • Review fluid analysis and related diagnoses
Definition • Procedure in which a sterile needle and syringe is used to draw fluid from a joint
Why do an arthrocentesis? • To diagnose and establish the cause of monoarthritis or polyarthritis • Presence of joint infection • Cause of arthritis eg. Gout • To provide therapeutic relief for joint effusions
Procedural Technique • Factors taken into account • Needle size • Syringe size • Skin sterilization • Local anesthesia
Procedural Technique • Needle size – • 22 gauge probably adequate • Smaller for smaller joints • Larger if effusion is large knee collection eg 20 gauge • Syringe size – 5ml, larger if needed • Can be done under ultrasound guidance • Best strategy is to use one needle size and one syringe size
Procedural Technique • Skin preparation – three separate concentric outward spirals with an agent such as chlorhexidine prep • Local anesthesia – lidocaine, ethyl chloride spray. • Option to use no anesthesia
What to do once fluid is obtained? • Fluid analysis should include – • cell count with differential • Cultures • gram stain • Crystal – should be done promptly to avoid disintegration and false negative results
Normal Synovial Fluid • Highly viscous • Clear • Essentially acellular • Protein concentration approx. 1/3 of plasma • Glucose concentration similar to plasma
Categories of Joint Effusions • Noninflammatory – • Degenerative joint disease • Trauma • Osteonecrosis • Neuropathic arthropathy • Early or subsiding inflammation • Hypertrophic osteoarthropathy • Rheumatic fever • SLE • Sarcoidosis • Scleroderma
Categories of Joint Effusions • Inflammatory – • RA • Acute crystal-induced synovitis • Reactive arthritis • Ankylosingspondylitis • Psoriatic arthritis • Arthritis associated with inflammatory bowel disease • Rheumatic fever • SLE • Sarcoidosis
Categories of Joint Effusions • Septic effusions – • Bacteria • Mycobacteria • Fungus • Hemorrhagic – • Hemophilia • Anticoagulation • Scurvy • Trauma • Tumor • Neuropathic arthropathy
Categories of Joint Effusions Sterile processes such as reaction to intraarticular injections, flares of RA, leukemic infiltration and gout can cause synovial fluid elevations >100K
Key Messages • Know indication for procedure • Know what analysis should be performed on fluid obtained • Know how to interpret fluid results
References • Krey PR, Bailen DA. Synovial fluid leukocytosis. A study of Extremes. Am J Med 1979; 67:436 • Zuber TJ. Knee Joint Aspiration and Injection. Am Fam Phys 2002; 66:1497 • Mimoz O, Karim A. Chlorhexidine compared with povidone-iodine as skin preparation before blood culture. A randomized, controlled trial. Ann Intern Med 1999; 131:834 • Shmerling RH, Delbanco TL. Synovial fluid tests. What should be ordered? JAMA 1990; 264:1009. • Guidelines for the initial evaluation of the adult with acute musculoskeletal symptoms. American College of Rheumatology Ad Hoc Committee on Clinical Guidelines. Arthritis Rheum 1996; 39:1