Infectious arthritis (septic arthritis) is caused by a bacterial, viral, or fungal infection inside a joint. The infection may be caused by an illness or may spread from an infection in a wound near a joint.
The large joints, such as the hips, knees, shoulders, and elbows, are most often affected. Infectious arthritis usually affects one joint, but it can affect many joints. Symptoms may include:
Immediate treatment with antibiotics and, possibly, surgical drainage of the affected joint can prevent the spread of the infection, the destruction of the joint, and even death.
WebMD Medical Reference from Healthwise