• Also Known As:
  • Infectious Arthritis
  • Bacterial Arthritis
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What is septic arthritis?

Septic arthritis, also called infectious arthritis, is an infection in a joint cavity. The infection may spread from another part of the body or it can be introduced directly to the joint during an injury, injection or surgery. Most commonly, septic arthritis results from bacterial infections caused by staphylococci, streptococci or Neisseria gonorrhoeae, but it may also be caused by a fungal or viral infection.

The condition is typically acute, quickly causing severe pain in a single joint. Symptoms include inflammation and swelling, redness, joint immobility, and in some cases fever and chills. Occasionally, symptoms may evolve more slowly and become chronic. Septic arthritis can affect any joint but is most frequently found in the knee, hip, shoulder, wrist, elbow, and finger joints. Usually only one joint will be affected, but in some cases there may be more than one. This condition needs to be diagnosed and treated quickly because it can destroy joints in a short period of time.

Septic arthritis can occur in people who have had a recent traumatic joint injury, had joint surgery or joint replacement, or had a blood infection (bacteremia or septicemia). Prosthetic joint infections are becoming increasingly common. Additional risk factors for septic arthritis include having certain underlying illnesses like diabetes or anemia, a weakened immune system or the presence of an indwelling catheter. Conditions such as gout, osteoarthritis, or rheumatoid arthritis may also predispose someone to septic arthritis. Approximately 45% of the people reported to have developed septic arthritis are over the age of 65. Those with skin conditions such as psoriasis, eczema, or skin infections are also at increased risk. In younger, sexually active adults, the most common cause is Neisseria gonorrhoeae.

Sometimes the microorganisms that cause Lyme disease, HIV, viral hepatitis, parvovirus B19, mumps, or rubella can infect a joint. Chronic septic arthritis, which tends to be less painful and slower to develop, is less common and tends to be caused by microorganisms such as Mycobacterium tuberculosis, which causes tuberculosis (TB), and Candida albicans, a yeast infection.


About Septic Arthritis


Laboratory testing related to septic arthritis is important to identify the microbe causing the infection, to determine which antimicrobial therapy will be effective, to monitor the effectiveness of treatment, and to evaluate the physical status of the affected joint(s).

Laboratory tests:

  • Synovial (joint) fluid analysis – to detect the presence of inflammatory cells or crystals that may indicate either an infectious or non-infectious cause (just as gout) for joint pain and symptoms
  • Culture of joint fluid – to detect the presence of bacteria, mycobacteria, or yeast in the joint in order to determine the antimicrobials to which they are susceptible and to evaluate the effectiveness of treatment
  • Blood culture – to determine if a microbe is present in the blood
  • Complete blood count (CBC) – to determine the presence and number of red and white blood cells that would indicate reaction to an infection to help evaluate and monitor the condition
  • Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) – to detect inflammation; useful in following response to therapy

Non-laboratory tests:

  • X-ray of joint(s) – to help evaluate joint damage; may not show abnormalities until significant damage exists


Treatment for septic arthritis is given to eliminate the infection, reduce inflammation and associated fluid pressure on the joint, minimize joint damage, and maintain and/or recover joint mobility. Prompt treatment is essential to prevent the destruction of joints, which can occur within days or hours.

The primary treatment is joint drainage and appropriate antimicrobial therapy, which may require intravenous antibiotics.

Fluid is usually aspirated from the affected joint(s) to relieve pressure and to analyze in order to identify the specific microbe causing the infection. In some cases, surgery may be needed to drain the infected joint fluid.

The choice of medication prescribed will depend on the susceptibility of the microorganism to a panel of antibiotics tested and how effective the antimicrobials are at getting into the infected joint space. The health care provider may not wait, however, for the laboratory results before starting treatment to reduce the chances of joint destruction. With some organisms, such as mycobacteria, multiple drugs may need to be taken for extended periods of time. Viral infections will usually resolve without any antiviral therapy.

Patients may also be treated for inflammation and pain with a nonsteroidal anti-inflammatory drug (NSAID), and physical therapy may be recommended.

View Sources

Sources Used in Current Review

Brusch, John L., MD., Septic Arthritis. 2016. Available online at http://emedicine.medscape.com/article/236299-overview. Accessed July 24, 2017.

Carpenter, Christopher R., MD, et. al. 2011. Evidence-based Diagnostics: Adult Septic Arthritis. Academic Emergency Medicine. 18(8). Available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229263/. Accessed July 24, 2017.

Goldenberg, Don. L., MD. UpToDate. 2017. Patient education: Joint infection (Beyond the Basics). Available online at https://www.uptodate.com/contents/joint-infection-beyond-the-basics?view=print. Accessed July 24, 2017.

U.S. National Laboratory of Medicine. 2017. Infectious Arthritis. Available online at https://medlineplus.gov/infectiousarthritis.html. Accessed July 24, 2017.

Sources Used in Previous Reviews

MayoClinic.com. Septic arthritis. Available online at http://www.mayoclinic.com/health/bone-and-joint-infections/DS00545. Accessed June 2013.

Brusch JL, et al. Septic Arthritis. Medscape Reference. Available online at http://emedicine.medscape.com/article/236299-overview. Accessed June 2013.

MedlinePlus Medical Encyclopedia. Septic arthritis. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000430.htm. Accessed June 2013.

Horowitz, DL et al. Approach to Septic Arthritis. Am Fam Physician. Sep 15;84(6):653-660. Available online at http://www.aafp.org/afp/2011/0915/p653.html. Accessed June 2013.

Boston Children’s Hospital. Septic (Infectious Arthritis). Available online at https://childrenshospital.org/az/Site1065/mainpageS1065P1.html. Accessed June 2013.

NYU Langone Meical Center. Septic Arthritis. Available online at http://medicine.med.nyu.edu/conditions-we-treat/conditions/septic-arthritis. Accessed June 2013.

AccessMedicine. Chronic Septic Arthritis. Available online at http://www.accessmedicine.ca/content.aspx?aID=2321500&searchStr=Septic+arthritis. Accessed June 2013.

Peng, S. (2005 April 20, Updated). Non-gonnococcal (septic) bacterial arthritis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000430.htm.

Mayo Clinic Staff (2006 July 31). Septic arthritis. MayoClinic.com [On-line information]. Available online at http://www.mayoclinic.com/health/bone-and-joint-infections/DS00545.

(2003 February 1, Reviewed/Revised). Infectious Arthritis. Merck Manual Home Edition [On-line information]. Available online at http://www.merck.com/mmhe/print/sec05/ch065/ch065c.html.

MedlinePlus Medical Encyclopedia. Septic arthritis. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000430.htm. Accessed October 2010.

The Merck Manual of Medical Information – Second home Edition. Infectious Arthritis. Available online at http://www.merck.com/mmhe/print/sec05/ch065/ch065c.html. Accessed October 2010; revised February 2008.