There have been sporadic reports in the literature of the coexistence of cystic fibrosis (CF) with various forms of arthritis.1-5 We have recently observed a case of classical, seropositive, adult-type rheumatoid arthritis in a female teenager with CF.
Report of a Case.—A 16-year-old girl had her condition diagnosed as cystic fibrosis at age 3 months, with a history of steatorrhea, respiratory symptoms, and a positive sweat electrolyte test; a brother had died from the same disease. Her growth and development were higher than the 50th percentile, and she had only minor morbidity from pulmonary or gastrointestinal symptoms. Her condition was intermittently treated with prophylactic antibiotics and she received a maintenance dose of daily pancreatic extract. As rated by the Schwachman score, her clinical CF status was "excellent."
At age 14 years, she noted the insidious onset of pain and swelling in the proximal interphalangeal (PIP) joints of the