What Causes Septic Arthritis?

Bacteria are the usual cause, although other germs can sometimes be responsible. Infection may travel through the bloodstream from another part of the body, enter through a wound near the joint, or follow an injection, operation or other joint procedure. Infection in nearby bone can also extend toward a joint. The affected joint may become suddenly painful, swollen, warm and difficult to move. Feeling unwell or having a fever can occur, but their absence does not safely exclude a joint infection.

A hot, swollen joint with rapidly increasing pain needs same-day medical assessment. Clinicians may examine the joint, take blood tests and draw a sample of joint fluid to identify the germ. Treatment commonly involves antibiotics and sometimes drainage of infected fluid. Do not massage the joint, force it through painful movement or rely on leftover antibiotics, because this can delay appropriate testing and treatment.

Go to urgent care or an emergency service for sudden severe joint pain with swelling, warmth, fever, chills, confusion, marked weakness or inability to use the limb. Seek prompt help after a joint wound or procedure if pain and swelling are worsening. Septic arthritis can damage the joint and affect overall health when treatment is delayed.

Could this be an infection inside the joint? Do I need joint-fluid testing? Which treatment is needed while results are pending? How will you check whether nearby bone or the bloodstream is involved?