Protracted bacterial bronchitis (PBB) and bronchiectasis are distinct diagnostic entities that share common clinical and laboratory features. It is postulated, but remains unproven, that PBB precedes a diagnosis of bronchiectasis in a subgroup of children. In a cohort of children with PBB, our objectives were to: (a) determine the medium-term risk of bronchiectasis and (b) identify risk factors for bronchiectasis and recurrent episodes of PBB.
161 children with PBB and 25 controls were prospectively recruited to this cohort study. A subset of 106 children was followed for 2 years. Flexible bronchoscopy, BAL and basic immune function tests were performed. CT chest was undertaken if clinical features were suggestive of bronchiectasis.
Of 161 children with PBB (66% male), 13 (8.1%) were diagnosed with bronchiectasis over the study period. Almost half (43.5%) with PBB had recurrent episodes (>3/year). Major risk factors for bronchiectasis included: H. influenzae lower airway infection (in BAL) (p=0.013) and recurrent episodes of PBB (p=0.003). H. influenzae infection conferred >7 times higher risk of bronchiectasis [HR 7.55 (95%CI 1.66 - 34.28), p=0.009] compared to absence of H. influenzae. The majority of isolates (82%) were nontypeable H. influenzae. No risk factors for recurrent PBB were identified.
PBB is associated with a future diagnosis of bronchiectasis in a subgroup of children. H. influenzae lower airway infection and recurrent PBB are significant predictors. Clinicians should be cognisant of the relationship between PBB and bronchiectasis and appropriate follow-up measures should be taken in those with risk factors.