EFFECTS OF UPPER RESPIRATORY-TRACT INFECTIONS IN PATIENTS WITH CYSTIC-FIBROSIS

Background - The polymerase chain reaction has improved the detection of picornaviruses and rhinoviruses and our understanding of their role in reversible airways disease. The effects of colds on lower respirat ory morbidity and bacterial colonisation in cystic fibrosis remain unc ertain. Methods - Children with cystic fibrosis were evaluated regular ly in the clinic and the parents notified the investigators when their child developed a cold. Nasopharyngeal specimens were collected at th e start of the infection for polymerase chain reaction, bacteriology w as also undertaken and again three weeks later, and pulmonary function was measured in children aged greater than or equal to 6 years at fou r day intervals for three weeks. The effects of colds on rate of progr ession of cystic fibrosis were assessed by pulmonary function, Shwachm an scores, and radiology. Results - Thirty eight children suffered 147 colds over 17 months. Picornaviruses were detected in 51 (43%) of 119 nasopharyngeal specimens, and 21 of the 51 were further identified as rhinoviruses. Pulmonary dysfunction was similar following picornaviru s and non-picornavirus infections; the mean change from baseline in fo rced expiratory volume in one second (FEV(1)) was -16.5% and -10.3% at 1-4 days and 21-24 days, respectively, after onset of a cold. Childre n who experienced more colds than average had evidence of disease prog ression with reduction in Shwachman score, increasing Chrispin-Norman score, and greater deterioration in FEV(1) per annum. Ten of 12 new ba cterial infections were associated with a cold. Conclusions - Picornav irus and non-picornavirus colds are associated with pulmonary function abnormalities and disease progression in patients with cystic fibrosi s, and predispose to secondary bacterial infection and colonisation.