(Bacterial Arthritis; Infectious Arthritis; Pyogenic Arthritis)
Septic arthritis is a serious infection of the joints caused by bacteria. This infection causes the joint to be filled with pus cells. These pus cells release substances directed against the bacteria. However, this action can damage the joint structures, bone, and surrounding cartilage.
Septic arthritis develops when bacteria spreads from the source of infection through the bloodstream to a joint. It can result from:
- Infection due to an injection
- Other infections
Septic arthritis can also be caused from injury or trauma. It can result from:
- A penetration wound
- An injury that affects the joint
- Joint surgery/replacement
Septic arthritis can strike at any age. However, it occurs most often in children aged three and younger. In infants, the hip is a frequent site of infection. In toddlers, it is the shoulders, knees, and hips. In children, the most common bacterial causes are:
- Staphylococcus aureus—staph infection
- Streptococcus species, such as group B strep infection
- Streptococcus pneumoniae—a common bacterial cause of pneumonia
Septic arthritis rarely occurs from early childhood through adolescence. After that, it occurs more often. In adults, it most commonly affects weight-bearing joints, such as the knees. In adults, the most common causes are:
- S. aureus
- Neisseria gonorrhoeae—the bacteria that causes gonorrhea
Joint Damage in Knee
Factors that may increase your chance of developing septic arthritis include:
- Diseases that weaken the immune system, such as HIV, or taking drugs that suppress immunity
- A history of joint problems or having other types of arthritis, gout, or lupus
- A history of IV drug use
- Chronic illnesses, such as anemia, diabetes, sickle cell, and kidney failure
- Joint replacement or organ transplant surgery
- Recent joint injections, such as cortisone or hyaluronic acid
- Skin conditions, such as psoriasis and eczema
Symptoms may include:
Newborn or infants
- Crying when a joint is moved, such as during a diaper change
- Inability to move the limb of a joint
- Swelling and redness
- Persistent crying for any reason
Children and adults
- Intense joint pain
- Joint swelling and redness
- Inability to move a joint or its limb
Your doctor will ask about you or your child’s symptoms and medical history. A physical exam will be done. Your doctor may refer you to a specialist.
Your doctor may need to test your bodily fluids. This can be done with:
- Testing joint fluids
- Blood tests
Images may be taken of your bodily structures. This can be done with:
- MRI scan
Antibiotic therapy is started as soon as a diagnosis is made. In the beginning, antibiotics are given by IV. This is to ensure that the infected joint receives medicine to kill the bacteria. The specific medicines used depend on the type of bacteria that is causing the infection. The remaining course of antibiotics may be given by mouth.
Fluid may be removed from the joint to reduce the likelihood of joint damage. This may be done either by placing a needle in the joint or through surgery.
Rest, preventing the joint from moving, and warm compresses may be used to manage pain. Physical therapy or exercises may also speed recovery.
If you are diagnosed with septic arthritis, follow your doctor's instructions.
To help reduce your chance of getting septic arthritis, get prompt treatment of infections that could lead to septic arthritis.
The Arthritis Foundation
National Institute of Arthritis and Musculoskeletal and Skin Disease
Arthritis Society of Canada
Ernst AA, Weiss SJ, et al. Usefulness of CRP and ESR in predicting septic joints. South Med J. 2010;103(6):522-526.
Howard A, Wilson M. Septic arthritis in children. BMJ. 2010;341:c4407.
Ma L, Cranney A, et al. Acute monoarthritis: what is the cause of my patient's painful swollen joint? CMAJ. 2009;180(1):59-65.
Septic arthritis. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated April 11, 2013. Accessed August 6, 2013.
Septic arthritis. Patient UK website. Available at http://www.patient.co.uk/health/septic-arthritis-leaflet. Updated April 28, 2010. Accessed August 6, 2013.
Last reviewed August 2013 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.