Septic arthritis is another way to say that the joint is infected. Sometimes the condition is called infectious or bacterial arthritis. There is usually an underlying systemic cause of the problem.
A recent history of any kind of infection such as pneumonia or urinary tract infection is the most common cause. Bacteria in one part of the body move via the bloodstream to another part of the body such as the joint. This process is called hematogenous seeding.
Other risk factors include older age (over 80 years old), sexually transmitted infections, diabetes, or chronic joint damage from gout or arthritis. Anyone who has had a joint replacement is at increased risk for joint infection. The infection can occur years after the implant is inserted. Anyone with an indwelling catheter is also at increased risk.
Symptoms may be mild to severe with low-grade fever and slightly swollen glands. There may be a skin rash prior to any joint symptoms. Fingers, knees, shoulders, and ankles are affected most often and usually on both sides.
Damage to the joint can be sudden and severe. Anyone with a recent history of infection who develops any of these symptoms along with joint pain should see a doctor right away. Early treatment with antibiotics is needed to prevent or limit joint destruction. Arthroscopic debridement to cleanse the joint may be needed.