Infectious Arthritis

Septic arthritis, also called as infectious arthritis, is characterized by joint inflammation due to a bacterial or fungal infection that usually affects the large joints of the body such as knee or hip. Normally, fluid lubricating a joint, called synovial fluid, is aseptic in nature. But with septic arthritis, microbes can grow in the affected joint fluid and make the condition worse.

Based on the duration and severity of the septic arthritis, it is categorized as:

  • Acute septic arthritis: It is more common, may develop suddenly and is considered more severe. The bacteria generally involved are staphylococcus or streptococcus.
  • Chronic septic arthritis: It is less common, develops slowly and is less severe. The involved microorganisms are mycobacterium tuberculosis and candida albicans.

Septic arthritis may affect individuals of any age. Children below 3 years (infants) are often affected by septic arthritis as compared to children of age 3 to adolescence. Infants generally show more infection in the hip region.

Causes and risks factors

Septic arthritis may be caused due to infection of microorganisms such as bacteria, viruses, and fungi. The infection may spread either through the bloodstream, or by injury or even during surgery. Among the different causes, bacterial infection is the most common.

Risks factors for developing septic arthritis includes various conditions such as artificial joint implants, intravenous (IV) injection, immunosuppressant drugs, joint injury, joint arthroscopy or other surgery and also certain chronic diseases such as diabetes, rheumatoid arthritis, and sickle cell anaemia.


The common symptoms associated with septic arthritis are:

  • Fever
  • Redness in the affected joint
  • Swelling in the joint
  • Joint pain that may get worse with movement

In severe cases, patients may not be able to move the limb of the infected joint, called as pseudo paralysis.


The diagnosis of septic arthritis includes examination of synovial fluid of the affected joint, blood culture, and X-rays.


Septic arthritis treatment includes specific antibiotics to treat the infection. Additional measures such as rest, keeping the joint motionless, elevating the joint and applying cold compresses may reduce symptoms. Certain exercises are also recommended for the recovery of the affected joint.

In cases of excessive accumulation of synovial fluid in the affected joint it is drained through a sterile needle. In severe cases, surgery may be employed for draining the infected joint fluid.