Protracted bacteria bronchitis (PBB) in children: natural history and risk factors for bronchiectasis

Aim: PBB and bronchiectasis are distinct clinical entities but share common clinical and laboratory features. It is postulated, but remains unproven, that protracted bacterial bronchitis is antecedent to adiagnosis of bronchiectasis. Ina cohort of children with PBB, our aims were to:a) determine the medium-term risk of bronchiectasis and b) identify risk factors for bronchiectasis and recurrent episodes of PBB.

Methods: 106 children with PBB and 25 controls were prospectively recruited (2008–2012) and followed for 2 years. Flexible bronchoscopy, bronchoalveolarlavage (BAL) and basic immune function tests were performed at baseline. Coughdiaries were completed during periods of illness and monthly contact withparents was made to capture respiratory exacerbations. HRCT chest was undertaken in those with clinical features suggestive of bronchiectasis.

Results: Of the 106 children with PBB (70% male), followed formedian 25 months (IQR 24, 28), 12% (n = 13) were diagnosed with BE on CT chest.Over half (62%) of children with PBB had recurrent episodes (>3 per year). The major risk factors for BE, on multi-variate analysis, were H. influenzaelower airway infection (p = 0.012) and having 2+ siblings (p = 0.040). H.influenzae lower airway infection conferred greater than 6 times higher risk ofBE, compared to H. influenzae negative state [hazard ratio 6.80 (95% CI 1.50–30.80), p = 0.013]. No risk factors for recurrent PBB were identified.

Conclusion: PBB is antecedent to a diagnosis of bronchiectasis in asubgroup of children. H. influenzae lower airway infection and having multiple siblings appear to be risk factors. Clinicians should be cognisant of the needto monitor children with PBB for future occurrence of bronchiectasis.