Septic arthritis (infectious arthritis)

Septic arthritis is a type of joint inflammation caused by an infection.

A medical diagram showing details of septic arthritis

Also called infectious arthritis, septic arthritis is a condition that can affect any joint, but typically occurs when one of the larger joints of the body (commonly the hip or knee) becomes infected.  

Septic arthritis causes include bacteria, viruses and fungi with the bacterial type being most prevalent – usually the result of a streptococcal or staphylococcal infection that spreads from elsewhere in the body. 

Risk factors for the development of septic arthritis include: 

  • Pre-existing joint issues such as rheumatoid arthritis, osteoarthritis, gout or joint trauma
  • Having a compromised immune system or using immunosuppressive drugs
  • Skin conditions or open wounds that allow bacteria access to the body

What are its symptoms?

Septic arthritis symptoms usually develop rapidly, over a few days or even just a few hours. Signs of septic arthritis include:

  • Severe discomfort and pain of the affected joint. Pain is worse with movement
  • Swelling and redness of the joint. The joint may also feel warm to the touch
  • General signs of infection such as fever, chills, malaise, and irritability in children

How is it diagnosed? 

Diagnosis of septic arthritis frequently relies on a test called an arthrocentesis. This test involves collecting a sample of the joint’s synovial fluid via needle aspiration. This is then examined for bacteria and other signs of infection, such as a high white blood cell count. 

Blood tests can also be used to determine whether your white blood cells are elevated or not. Imaging tests such as X-ray will be the next step, as these can allow medical professionals to see the extent of damage to the joint and make informed decisions about the best treatment options. 

What are your treatment options? 

Intravenous (IV) antibiotics are the mainstay of septic arthritis treatment, as these drugs are used to eliminate bacterial infections (the main cause of septic arthritis). It’s essential to begin treatment as quickly as possible, before the joint becomes irreversibly damaged. 

In most cases, the infected synovial fluid (the fluid that prevents friction between joints) will need to be drained with a needle and syringe or via a flexible drainage tube (a procedure called arthroscopy). Some joints may be difficult to drain using these procedures, in which case open surgery is necessary. This can also be used to remove damaged areas of the joint or replace a badly damaged joint entirely.

Can it be prevented?

The organisms that cause septic arthritis are common, so prevention of this condition needs to be focused on strengthening your ability to fight them off before they are able to infect a joint. This means treating all open wounds before they become infected and where infection has set in, treating it promptly and taking any medication exactly as instructed by your doctor.

It also means managing chronic conditions effectively and leading a healthy and well-balanced lifestyle and not smoking (a known lifestyle factor that can compromise immunity).

IMAGE CREDIT: 123rf.com

The accuracy of this information was checked and approved by physician Dr Thomas Blake in July 2016