PSORIATIC OR CYSTIC FIBROSIS ARTHROPATHY? DIFFICULTY WITH DIAGNOSIS AND MANAGEMENT

A 19-year-old man with cystic fibrosis developed arthritis at the age of 12 years. He also suffered from psoriasis, and was found to be HLA-B27 positive. His disease was episodic in nature for the first 5 years, but he later developed an unremitting erosive arthropathy which proved difficult to treat. KEY WORDS: Cystic fibrosis, Psoriasis, Spondyloarthritis, Treatment, Aetiology. THERE are over 5000 people currently alive in the United Kingdom with cystic fibrosis (CF) [1]. Recent studies have found the prevalence of arthropathy to vary from 5 % among patients of all ages [2] to 11.6 % of CF adults attending outpatients [3]. We would like to describe a young man who was pre-viously thought to have cystic fibrosis arthropathy [4]. He is now suffering from severe psoriatic spondylo-arthritis. Effective control of his disease has been difficult to achieve but intramuscular sodium aurothio-malate has been the most effective drug. We discuss whether this might be related to persistent bacterial antigen load, the synergistic effect of independent 'arthritogenic ' genes, and the poor and unpredictable absorption of oral medications. CASE REPORT The patient was born in 1970. At the age of 6 weeks he was admitted to hospital with right middle lobe pneumonia. A diagnosis of cystic fibrosis was confirmed by a sweat test sodium of 95 mmol/1 (normal up to 70 mmol/1). He has since taken pancreatic enzyme supplements. His growth and development have been normal [5]. Pseudomonas has never been isolated from his sputum. His pulmonary function tests in February 1989 showed moderate airways obstruction but lung volumes and gas transfer were normal. At age 9 months, psoriasis was first diagnosed. He has had a few small skin lesions and nail changes all his life. At 12 years of age he presented with a painful, swollen, red ankle. Septic arthritis was diagnosed, although no joint fluid was obtained and blood cultures were negative. Investigations at that time showed he was antinuclear factor negative, and seronegative for rheumatoid factor by SCAT and Latex tests. Major histocompatibility antigens were found to be HLA A