Bacillus Calmette-Guérin associated arthropathy mimicking undifferentiated spondyloarthropathy.

The development of an inflammatory arthritis mimicking an undifferentiated spondyloarthropathy (SpA) was seen in a patient being treated for a superficial bladder cancer with intravesical bacillus Calmette-Guérin (BCG). Physical findings included classic dactylitis of both feet. This is the fourth report identifying a patient with BCG induced articular findings suggestive of a SpA with dactylitis. Studies of BCG stimulated cytokine secretion from peripheral blood mononuclear cells showed the patient to have enhanced interleukin 6 (IL-6) levels and reduced interferon-gamma (IFN-gamma) levels. Spontaneous IL-6 secretion was markedly elevated for the patient, compared to the control subject, but IFN-gamma secretion was quite similar. No differences were apparent with IL-4.