Septic arthritis results from invasion of the synovium by microorganisms, and most infectious organisms can cause arthritis. In children, septic arthritis is usually associated with systemic infections such as pneumonia or meningitis; in young adults, gonococcal arthritis is the most common cause; and in the aged, septic arthritis is usually superimposed on chronic joint disease. Underlying rheumatoid arthritis is common, and Dr. Knights stresses the importance of recognizing septic arthritis as a complication of rheumatoid arthritis.
化脓性关节炎是由微生物侵入滑膜引起的，大多数感染性生物体都可导致关节炎。在儿童中，化脓性关节炎通常与肺炎或脑膜炎等全身性感染有关；在年轻人中，淋菌性关节炎是最常见的病因；而在老年人中，化脓性关节炎通常叠加于慢性关节疾病之上。潜在的类风湿关节炎很常见，奈茨医生强调了将化脓性关节炎识别为类风湿关节炎并发症的重要性。
