Tuberculous rheumatism (Poncet's disease) in a child.

A 2-year-old boy who had increasing difficulty walking and had large, warm, sterile knee and ankle effusions was found to have active vertebral tuberculosis and a large prevertebral abscess. Lymphocyte proliferation assays demonstrated increased purified protein derivative-induced reactivity of synovial fluid lymphocytes compared with peripheral blood lymphocytes. The arthritis responded rapidly to antituberculous and antiinflammatory drugs. This patient's disease represented an example of tuberculous rheumatism (Poncet's disease).