Common Causes And Risk Factors For Septic Arthritis

April 26, 2023

Septic arthritis is a painful joint infection that occurs when germs travel through the bloodstream from other parts of the body and settle in the joint, or when a deep injury delivers germs directly to the joint. Older adults and infants are at a higher risk of developing septic arthritis. It's most common for knees to be affected, but the shoulders, hips, and other joints can also be infected. Left untreated, septic arthritis can cause fast and severe damage to the bone and cartilage inside the joint. Treatment is done by draining the joint through surgery or a needle. A course of antibiotics might also help treat the infection. There are a number of causes and risk factors regarding septic arthritis. Uncover the details about them now.

Various Types Of Infections

Septic arthritis can develop because of various types of infections, including fungal, viral, and bacterial infections. Staph infections, a common bacterial infection, are most often cited as the cause. These infections are unusually common because the bacteria can live and survive on both healthy and infected skin, so individuals are at risk of developing an infection regardless of their overall health. Usually, septic arthritis develops when infections from elsewhere in the body spread via the bloodstream, lodging in the joint. These might include common infections like urinary tract infections or skin infections. Joints are lined by a material called synovium, which isn't designed to protect itself against infections. Since the joint is so susceptible to infection, the body responds with an inflammatory and strong immune response that contributes to the joint damage through increased pressure and swelling.

Weakened Immune System

Individuals with a weakened immune system have a higher chance of developing septic arthritis. Patients with kidney problems, liver problems, diabetes, immune-weakening viruses, and individuals taking immunosuppressants are in this increased risk category. Joints are already susceptible to germs and infection even in cases where the individual is healthy. When the joint becomes infected and the immune system can't destroy the infection, the condition just continues to worsen. The infection eats away at the joint and surrounding tissues. Joint cavities are small and enclosed, so infections can cause a huge amount of damage in very little time. While immune responses can contribute to joint damage, individuals with weakened immune systems will have infections that spread more rapidly. Delayed treatment can cause permanent joint damage and degeneration.

Joint Trauma

In less common cases, a surgery, drug injection, or puncture wound around or inside the joint can allow germs to enter the joint cavity. It's unusual for individuals to experience injuries that cause such direct access to the joint, which is why this method of infection is much rarer than infection from the bloodstream. Experiencing joint trauma puts individuals at a higher risk of developing septic arthritis, even if the wound doesn't appear to be on the joint itself. While deep punctures are the most common methods of infection, it's possible shallow wounds might also lead to germ transmission. The risk also increases if the cause of the injury was unsanitary. For example, animal bites or punctures from dirty needles can transmit germs much more easily than clean cuts. If an individual is injured around or on their joint, it's important for them to clean and bandage the wound as soon as possible. They should also monitor it closely for signs of infection.

Rheumatoid Arthritis

Rheumatoid arthritis is a condition where the immune system creates antibodies that attack joint tissue. Normally, antibodies are supposed to attack viruses, infections, and other invasive substances. The mistaken system-attacking antibodies make this condition an autoimmune disease, a class of illnesses caused by immune system malfunctions. Typical treatments for rheumatoid arthritis include immune-suppressing medications. Like with patients whose immune systems are weakened due to illness, this can cause the infection to progress and cause more damage. It's also difficult to get a septic arthritis diagnosis when an individual has rheumatoid arthritis, because many of the symptoms are very similar. Some rheumatoid arthritis patients don't realize their condition is something other than the usual pain, swelling, and inflammation until it's too late. For this reason, it's important for patients with rheumatoid arthritis to be aware of the risks of septic arthritis. They should be informed of the potential causes and warning signs so they can seek prompt medical treatment.


Osteoarthritis is just one of several conditions that can increase an individual's risk of developing septic arthritis. When a patient already has problems with their joints, the joints are more susceptible to infection due to weakness and prior damage. Chronic joint conditions like osteoarthritis, lupus, and gout are often seen alongside septic arthritis cases. Osteoarthritis most commonly affects the joints in an individual's spine, hips, hands, and knees, though it is possible for any joint to be affected. Typically, symptoms include joint stiffness, pain, and tenderness, as well as a grating sensation when the affected joint is used, a loss of flexibility in the joint, as well as bone spurs. It is crucial for osteoarthritis patients to receive appropriate and prompt treatment in order to mitigate the potential for septic arthritis to develop.

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