Causes of Knee Effusions - Differential Diagnosis Framework Knee Effusion Red Flags: 1. Fever/Chills/Joint pain/Night sweats/Weight loss - DDX: - Infection - Systemic disease - Malignancy 2. Non-weight bearing after injury 3. Loss of signal pulses 4. Loss of sensation distal to the knee Infectious Knee Effusions - Septic Arthritis: - Staphylococcal (40%) - Streptococcal (28%) - Gm - bacilli (19%) - Mycobacterium (8%) - Gm - cocci (3%) - Gram + bacilli (1%) - Anaerobes (1%) - Watch out for: - Gonorrhea - Lyme’s disease - Syphilis - Tuberculosis - Brucellosis - Viruses: HIV, Chikungunya - Herpes virus: CMV, HSV, Varicella, EBV - Parvovirus - Hepatitis B, C - Rubella - Alphavirus - Fungi: Sporotrichosis, Coccidiomycosis, Candidiasis Inflammatory Knee Effusions: - Gout - Pseudo gout - Osteoarthritis - Overuse syndrome - Spondyloarthritis: - Reactive arthritis - Inflammatory bowel disease - Rheumatoid arthritis - Juvenile RA/Idiopathic arthritis - SLE - Behcet Disease Post-Infectious Knee Effusions: - Seronegative Reactive Syndrome - Acute rheumatic fever - Poststreptococcal reactive arthritis Traumatic Knee Effusions: - Ligamentous injuries - Meniscal injury - Intra-articulation fracture - Patellar dislocation Malignant Knee Effusions: - Hematologic - Leukemia - Ewing’s sarcoma - Giant cell tumor - Osteosarcoma - Eosinophils granuloma - Synovial sarcoma - Chondroblastoma - Benign Tumors: - Aneurysmal bone cyst - Osteochondroma Hematologic Knee Effusions: - Hemarthrosis - Hemophilia - Synovium - Oral anticoagulant therapy - Sickle cell disease Dr. Ravi Singh @rav7ks #Knee #Effusions #causes #differential #diagnosis #msk #physicalexam
