Analysis of bronchial biopsies in chronic cough.

BACKGROUND: Chronic cough is commonly associated with asthma, gastro-oesophageal reflux disease and postnasal drip, but in a significant proportion, no associated cause can be found. We determined whether examination of bronchial biopsies would be useful in determining the cause associated with chronic cough.

METHODS: 100 consecutive patients referred to a specialist cough clinic underwent a systematic assessment including a fiberoptic bronchoscopy for bronchial biopsies.

RESULTS: In 38 patients, treatment of associated causes led to amelioration of cough ('explained') and in 62, there was no association or improvement ('idiopathic'). The latter group had a longer duration of cough, a lower FeNO levels and a more sensitive capsaicin cough response, with an increase in basement membrane thickness with no differences in goblet cell hyperplasia and seromucinous hyperplasia, and in lymphocyte, neutrophil and eosinophil counts. The duration of cough was inversely correlated with the degree of neutrophil infiltration.

CONCLUSION: We conclude that pathological examination of bronchial biopsies is unlikely to be useful in the diagnosis of chronic cough in non-smokers.