What is septic arthritis?
Septic arthritis is an infection in the joint (synovial) fluid and joint tissues.
It occurs more often in children than in adults. The infection usually reaches the
joints through the bloodstream. In some cases, joints may become infected due to an
injection, surgery, or injury.
What causes septic arthritis?
Different types of bacteria, viruses, and fungi can infect a joint. The types that
can cause septic arthritis include:
- Staphylococci. These are common bacteria that often cause skin infections.
- Haemophilus influenzae. These are bacteria that can infect the larynx, trachea, and bronchi.
- Gram negative bacilli. This is a group of bacteria that includes E. coli.
- Streptococci. This is a group of bacteria that can lead to a wide variety of diseases.
- Gonococci. This is the bacterium that causes gonorrhea.
- Viruses. Viruses such as HIV can infect the joints of people of all ages.
The most common type of bacteria that causes septic arthritis is called Staphylococcus
aureus. It is also known as S. aureus. The bacteria can enter the body in a number
of ways, such as:
- A broken bone that goes through the skin (open fracture)
- An infection that spreads from another place on the body, such as the skin or genitals
- An infected wound
- Foreign object that goes through the skin
- Injury that breaks the skin
Who is at risk for septic arthritis?
Risk factors for septic arthritis include:
- A systemic blood-borne infection
- IV drug use
- Past history of septic arthritis
- Rheumatoid arthritis
Other factors that may increase the risk for septic arthritis include:
- Lung or liver disorders
- Old age
- Suppressed immune system
What are the symptoms of septic arthritis?
The most common joints affected by septic arthritis are the knee, hip, shoulder, elbow,
wrist, and finger. Most often, only one joint is affected. Symptoms can occur a bit
differently in each person, but common symptoms include:
- Joint pain
- Joint swelling
The symptoms of septic arthritis can look like other health conditions. Make sure
you see your healthcare provider for a diagnosis.
How is septic arthritis diagnosed?
Early diagnosis of septic arthritis is important. This is to prevent permanent damage
to the joint. The process starts with a medical history and a physical exam. Tests
may also be done, such as:
- Removal of joint fluid. This is done to check for white blood cells and bacteria.
- Blood tests. These are done to look for bacteria.
- Phlegm, spinal fluid, and urine tests. These are done to look for bacteria and find the source of infection.
How is septic arthritis treated?
Treatment will depend on your symptoms, age, and general health. It will also depend
on how severe the condition is.
Septic arthritis often needs treatment right away with antibiotics. This can improve
symptoms within 48 hours. Some infections caused by fungi need treatment with antifungal
medicine. Viral infections are not treated with medicine.
Fluid called pus may be drained from the joint. A buildup of pus can damage the joint.
The pus is drained with a needle, tube, or surgery. It is possible that pus may need
to be drained multiple times from the joint over the course of treatment. Other treatment
- Medicines for pain and fever
- Physical therapy to keep muscle strength
- A splint on the joint to relieve pain
What are the complications of septic arthritis?
Septic arthritis can destroy the joint cartilage. This can cause permanent damage
to the joint.
When should I call my health care provider?
If your symptoms get worse or you have new symptoms, let your healthcare provider
Key points about septic arthritis
- Septic arthritis is an infection in the joint (synovial) fluid and joint tissues.
- Different types of bacteria, viruses, and fungi can infect a joint.
- Symptoms include fever, joint pain, swelling, redness, and warmth.
- Quick treatment with antibiotics is needed to halt the risk of joint damage.
- Other treatments include medicines for pain and fever, drainage of the joint, physical
therapy, and a splint.
Tips to help you get the most from a visit to your healthcare provider:
- Know the reason for your visit and what you want to happen.
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you.
- Know why a new medicine or treatment is prescribed, and how it will help you. Also
know what the side effects are.
- Ask if your condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if you do not take the medicine or have the test or procedure.
- If you have a follow-up appointment, write down the date, time, and purpose for that
- Know how you can contact your healthcare provider if you have questions.