Septic arthritis (also known as infectious arthritis) is caused by an infection in the body. Unlike reactive arthritis (sometimes referred to as post-infectious arthritis), in which inflammation in a particular joint develops following an infection elsewhere in the body, septic arthritis occurs in the same joint as the offending infection. With only about 20,000 cases each year in the United States, septic arthritis is a relatively rare type of arthritis. Infants, people older than 65, and those with compromised immune systems are more likely to be affected by septic arthritis.

The pathophysiology of septic arthritis – or how the disease occurs – is when organisms such as viruses, bacteria, or fungi enter the joint space directly (as in the case of an injury or injection that breaks the skin) or through the bloodstream from another source of infection. Some of the most common causes of septic arthritis include the use of prosthetic joints, Lyme disease, or the bacterium Staphylococcus aureus (staph).

Symptoms of septic arthritis typically include low-grade fever, pain, and impaired range of motion. The hip and knee are most commonly affected and may become swollen, red, and warm.

Prompt identification and treatment is important to prevent permanent damage to the joint. If not treated, the condition may become extremely severe. Septic arthritis in children should be considered an orthopedic emergency.

Your doctor will collect information about how your symptoms developed and do some tests to diagnose septic arthritis. Treatment includes timely drainage of synovial fluid from the infected joint, antibiotic treatment (if the cause is determined to be bacterial), and minimizing movement of the joint to control pain.

While there are no official guidelines on nutrition for septic arthritis, a nutrient-rich diet that can help prevent or fight infection may be beneficial. In addition, reducing potentially inflammatory foods and increasing anti-inflammatory ones may improve the symptoms of and recovery from septic arthritis.