A painful infection in a joint caused by bacteria.

Bacterial arthritis happens when a bacterial infection moves to a joint. The infection most often affects knees. But it also can affect hips, shoulders and other joints. Quick treatment is needed to keep joints from being damaged.

Besides pain, symptoms include joint swelling and trouble using the joint. The joint can be swollen and warm and have a color change in the skin over the joint. There might be fever.

Treatment involves draining the joint and taking antibiotics, at first through a vein in the arm. Then antibiotics taken by mouth might be used.

A painful bacterial infection in a joint.