Differential Diagnosis Based on Synovial Fluid Classification*†
Type of Effusion | Possible Causes |
|---|---|
Hemorrhagic | Anticoagulants Hemangioma Neurogenic (neuropathic) arthropathy Pigmented villonodular synovitis Thrombocytopenia (rarely) Trauma with or without fracture Tumor |
Infectious | Various organisms depending on patient characteristics (see table Organisms That Commonly Cause Acute Infectious Arthritis) |
Inflammatory | Acute crystal synovitis (gout and calcium pyrophosphate arthritis [pseudogout]) Partially treated or less virulent bacterial infections Systemic lupus erythematosus (mild inflammation) Synovial infarction (eg, caused by sickle cell disease) |
Noninflammatory | Hypertrophic pulmonary osteoarthropathy (including clubbing) Metabolic diseases causing osteoarthritis Neurogenic (neuropathic) arthropathy Osteochondritis dissecans Osteonecrosis (including osteonecrosis caused by sickle cell disease) Subsiding or early inflammation Trauma |
Also see table Classification of Synovial Effusions. This differential diagnosis is only a partial listing. | |
† Some disorders span classifications (eg, neuropathic arthropathy can be hemorrhagic or noninflammatory; systemic sclerosis can be inflammatory or noninflammatory). | |