Within a few days of onset can destroy cartilage.
Bacteria enter the joint and lodge on the synovial membrane which causes an acute inflammatory response.
Bacteria organisms enter the synovial fluid since synovial tissue has no basement membrane and a purulent joint results.
Staphylococci and streptococci are the most common nongonococcal bacterial joint infection isolates.
Majority of cases are monoarticular and occur most frequently in larger peripheral joints, such as the knee.
The knee accounts for approximately 50% of cases.
Classical presentation is of an acutely swollen, painful joint with limited range of motion.
Chills and fever are common, but may be absent.
Arthrocentesis is a mandatory process when septic arthritis is suspected.
Synovial fluid is evaluated with white blood cell count differential, Gram stain, and culture to confirm diagnosis and help in treatment plan.
Early in the process x-ray examinations are normal and MRI imaging findings are imprecise.
Diagnosis confirmed by positive synovial fluid Gram stain or culture.
Mortality of in-hospital septic arthritis 7-15%, despite antibiotic use.
Increased incidence in rheumatoid arthritis and in the presence of joint prostheses.
Risk factors include individuals over the age of 80 years, recent joint surgery, hip or knee prostheses or skin infections, rheumatoid arthritis and HIV infection
Differential diagnosis of acute monoarthritis include: infection-(bacterial, fungal, mycobacterial, viral and spirochetal), rheumatoid arthritis, gout, pseudogout, apatite related arthropathy, reactive arthritis, systemic lupus erythematosus, Lyme arthritis, sickle cell disease, dialysis related amyloidosis, transient synovitis of the hip, plant thorn synovitis, hemarthroses, metastatic carcinoma, pigmented villonodular synovitis, neuropathic arthropathy, osteoarthritis and intra-articular injury.