Infectious arthritis

Infectious arthritis, also known as septic arthritis is a joint infection mostly in infants and elderly people. Knees, hips, shoulders and other joints are commonly affected by infectious arthritis.

There are two types of infections:

Acute infections – They account for 95 % of the infectious arthritis cases. Cartilage damage occurs within hours or days.

Chronic infections – They develop gradually over weeks. These infections are seen in people who are at high risk.

The infection can damage the cartilage of the joint. So, prompt treatment is essential to reduce joint damage. If the infection is left untreated, it may lead to joint degeneration and permanent damage. Osteoarthritis may also occur due to chronic infectious arthritis.


Symptoms of infectious arthritis include:

  • Severe pain in the joint
  • Difficulty to move the affected joint
  • Redness
  • Swelling
  • General weakness
  • Fever and chills
  • Loss of appetite

The symptoms may vary depending on the cause or the underlying disease.

Risk factors

History of joint problems such as arthritis, lupus, and gout, history of joint surgery, presence of open wounds, history of cancer and diabetes, having weak immune system, and smoking are some of the risk factors for infectious arthritis. Joint trauma such as animal bites or cuts also increases the risk of infectious arthritis.

Conditions such as Lyme disease, tuberculosis, gonorrhea, and staphylococcus infections also lead to infectious arthritis.


The treatment for infectious arthritis includes the use of medications and surgical joint drainage. Your doctor chooses the medications for effective treatment based on the diagnostic results.

Joint drainage is the procedure involving removal of synovial fluid from the infected joint. Your doctor may drain the joint fluid by inserting a needle or using arthroscopy.

Arthroscopy is a device inserted into the joint through a small incision. Then the suction and the drainage tubes are inserted around the joint to drain the fluid. In some instances such as infection in a hip joint, open surgery is performed to drain the fluid. Antibiotics are given if the underlying cause is bacteria. The treatment lasts for two to six weeks. Nausea, vomiting, and diarrhea are the common side effects that can be seen with the use of antibiotics. Antifungals are prescribed if causative organism is a fungus. If a virus is causing infectious arthritis, no treatment is given.


Infectious arthritis occurs due to bacterial, fungal, or viral infections. Staphylococcus aureus is the common bacterial species that lives on the healthy skin. But when the skin infection or urinary tract infection occurs or when there is a wound, skin puncture, or surgery, it enters the blood stream and results in infection of the joint.


Your doctor may ask you questions about symptoms and perform a physical examination.

Arthrocentesis (joint fluid analysis) is carried out to diagnose infectious arthritis. A sample of synovial fluid (joint fluid) is collected by inserting a needle. The sample is sent to a laboratory for the examination of appearance, consistency, and the presence of white blood cells.

Blood tests are performed to assess the signs of infection. Imaging tests are performed to evaluate the damage to the affected joint. Ultrasonography is performed to identify the pus formation.