Aseptic gonarthritis, presenting symptom of X-linked agammaglobulinemia ina five year old boy

A non-traumatic and sterile effusion of the knee joint was the presenting s ymptom of agammaglobulinemia in a five year old boy. The patient had experi enced recurrent infections, but these had been localized and responded to a ntibiotics so that the disease had not been diagnosed before. Synovitis of the knee was demonstrated by ultrasonography, while HRCT of the lungs showe d thickening and dilatation of bronchial walls. Complete recovery of gonart hritis was achieved following intravenous gamma globulin substitution. Discussion: Agammaglobulinemia has to be considered in the presence of an a traumatic and sterile monarthritis of the knee. Ultrasonography is a valuab le diagnostic tool in demonstrating synovitis.