Polyarthritis associated with hydatid disease of the liver

Clinical presentation of hydatid disease is depending on immunological background of the patient. Articular site of the parasite can give rise either to a veritable echinococcal arthritis or to a synovial affection that do not depend on living larva. A 77-year old man who had hydatid disease of the liver since two years, presented with progressive onset arthritis. Laboratory studies showed inflammatory changes but no evidence of immunological disorders was noticed. Abdominal imaging revealed multiple hydatid cysts of the liver. Ankle synovial fluid evaluation was positive of antibodies for hydatid antigen and negative of echinococcal larva. Excision of the hydatid cyst was accompanied by full remission of the arthritis with no recurrence. A reactive immune mechanism triggered by a parasite located at a distant side appears to be responsible for this type of arthritis. This data support the potential of echinococcosis granulosus in inducing a veritable aseptic arthritis as a response to intense immunological disorders.