Septic Arthritis
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Overview
Plain-Language Overview
Septic arthritis is a serious joint infection that affects the body's musculoskeletal system. It occurs when bacteria or other germs enter a joint, causing intense pain, swelling, and redness. The infection can rapidly damage the joint, leading to loss of movement and long-term problems if not treated quickly. The most commonly affected joints are the knee, hip, and shoulder. This condition mainly impacts the joint's ability to function properly and can cause fever and general illness. Early recognition and treatment are crucial to prevent permanent joint damage.
Clinical Definition
Septic arthritis is an acute infection of a synovial joint characterized by the invasion of the joint space by pathogenic microorganisms, most commonly Staphylococcus aureus. The infection leads to an intense inflammatory response with accumulation of purulent synovial fluid, causing rapid joint destruction if untreated. It typically presents with monoarticular joint pain, swelling, erythema, and decreased range of motion, often accompanied by systemic signs such as fever. Risk factors include preexisting joint disease, immunosuppression, and recent joint surgery or injection. The condition is a medical emergency due to the risk of irreversible cartilage damage and systemic sepsis.