Cystic fibrosis arthritis. A report of five cases.

In a retrospective study of 206 patients with cystic fibrosis (CF), five cases of CF arthritis were recorded. This is a frequency of 2.5% and of 4.5% in patients aged over 10. Four patients had episodic arthritis, which was related to the course of pulmonary disease in two cases. In three patients, synovial fluid examination revealed minimal evidence of inflammation. In one of these three cases, synovial biopsy revealed a mild and non-specific synovitis. The fifth patient had chronic arthropathy and was positive for rheumatoid factor, but did not fulfil the criteria for rheumatoid arthritis. There were no radiographic abnormalities in any of these cases. CF arthritis is a rare syndrome of unknown pathogenesis.