Infectious arthritis

1. Big picture

Infectious arthritis is a do-not-miss rheumatology emergency. The examiner mainly wants you to recognize the hot swollen joint, perform urgent arthrocentesis, start empirical antibiotics after cultures, and understand that delayed treatment destroys cartilage rapidly.

The key clinical rule:

Acute monoarthritis = septic arthritis until proven otherwise.

Do not treat a painful hot joint as “gout” or “arthritis flare” before excluding infection, especially if there is fever, severe pain, immunosuppression, prosthesis, diabetes, rheumatoid arthritis, recent joint injection, trauma, or bacteremia.