An Overview of Septic Arthritis Causes
The cause of
septic arthritis is a bacterial infection within a joint or joints. These bacteria cause inflammation within the joint that can ultimately lead to damage to the cartilage (the slippery coating at the end of bones), underlying bone, and joint capsule.
Causes of Septic Arthritis by Age
In infants under one year of age, the most common cause of septic
arthritis is
Staphylococcus aureus or Group B Strep.
Haemophilus influenzae and
Staphylococcus aureus are the most common causes of septic arthritis in children under five years of age.
Staphylococcus aureus is the most common cause in children five years of age and older. For adults, the most common cause of septic arthritis is an infection with
Neisseria gonorrhoeae (the bacteria that cause
gonorrhea).
Mycobacterium tuberculosis, which causes tuberculosis (TB), can also cause septic arthritis. Infection with the bacteria that causes
Lyme disease (
Borrelia burgdorferi) is another possible cause of septic arthritis.
Septic Arthritis Risk Factors
Arthritis research scientists have shown that people with certain risk factors are more likely than others to develop septic arthritis. A risk factor is anything that increases a person's chances of developing a disease. Having risk factors for septic arthritis does not guarantee that a person will develop the condition; it just increases his or her chances of developing it.
- Age (infants and young children are at greatest risk for the condition)
- Infection in another part of the body, especially infection within bone (known as osteomyelitis)
- Alcoholism or IV drug abuse
- Immunosuppressive medicines
- Chronic arthritis
- Rheumatoid arthritis, gout, or osteoarthritis
- Previous joint damage
- A history of recent steroid injections into the joint
- Having recently undergone certain procedures, such as a knee replacement, hip replacement, or knee arthroscopy.