How common is joint swelling in septic arthritis?

Septic arthritis is an infection inside a joint. The joint may become swollen, hot, red, and intensely painful, with movement becoming difficult. A knee, hip, shoulder, wrist, or another joint can be affected. Fever or feeling unwell may occur, but their absence does not safely rule out infection. The appearance can overlap with gout, an inflammatory arthritis flare, or an injury. A clinician may need to examine the joint and take fluid or blood samples to identify the cause and choose treatment.

Treat a new hot swollen joint as a same-day medical problem, especially when pain is severe or movement is restricted. Do not massage the joint, exercise through severe pain, or wait several days to see whether it settles. Tell the clinician when symptoms began, whether you have fever or chills, any recent wound or procedure, and your medicines or health conditions. Rest the limb in a comfortable position while arranging care, and follow local urgent-care advice.

Seek emergency care now for a swollen painful joint with confusion, faintness, breathing difficulty, rapidly worsening illness, or inability to move the limb. Urgent assessment is also needed for fever, chills, or a hot red joint. Infection can injure cartilage and spread beyond the joint, so early evaluation is safer than observing symptoms at home.

Could this be an infection inside the joint? Do I need joint-fluid or blood testing? Which symptoms mean I should return immediately? How should I move or protect the joint while treatment is arranged?