Chronisch-rezidivierende Gonarthritis und Autoimmunneutropenie

Isolated gonarthritis is a frequent manifestation in arthritis of infectious or noninfectious origin in childhood. The clinical presentation is not always classical with difficulties in differentiating both entities. We report the case of a patient with chronic recurrent gonarthritis and autoimmunneutropenia. Initially he had only mild symptoms and synovial cultures and eubacterial Polymerase Chain Reaction (PCR) did not reveal an infectious agent. He did not achieve remission by using anti-inflammatory therapy consisting of Non Steroidal Inflammatory Drugs (NSAID), Methotrexate and intraarticular corticosteroids. After normalization of neutrophils, he suffered from (paradoxic) exacerbation of gonarthritis. Eventually, Mycobacterium kansasii was cultured. After surgical lavage, initiation of triple antimycobacterial therapy, and changing NSAID therapy to indometacine he finally recovered.