title: Protracted Bacterial Bronchitis in Children: Natural History and Risk Factors for Bronchiectasis.
abstract: BACKGROUND
  Protracted bacterial bronchitis (PBB) and bronchiectasis are distinct diagnostic entities that share common clinical and laboratory features. It is postulated, but remains unproved, that PBB precedes a diagnosis of bronchiectasis in a subgroup of children. In a cohort of children with PBB, our objectives were to (1) determine the medium-term risk of bronchiectasis and (2) identify risk factors for bronchiectasis and recurrent episodes of PBB.
  
  
  METHODS
  One hundred sixty-one children with PBB and 25 control subjects 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. Chest CT was undertaken if clinical features were suggestive of bronchiectasis.
  
  
  RESULTS
  Of 161 children with PBB (66% boys), 13 were diagnosed with bronchiectasis over the study period (8.1%). Almost one-half with PBB (43.5%) had recurrent episodes (> 3/y). Major risk factors for bronchiectasis included lower airway infection with Haemophilus influenzae (recovered in BAL fluid) (P = .013) and recurrent episodes of PBB (P = .003). H influenzae infection conferred a more than seven times higher risk of bronchiectasis (hazard ratio, 7.55; 95% CI, 1.66-34.28; P = .009) compared with no H influenzae infection. The majority of isolates (82%) were nontypeable H influenzae. No risk factors for recurrent PBB were identified.
  
  
  CONCLUSIONS
  PBB is associated with a future diagnosis of bronchiectasis in a subgroup of children. Lower airway infection with H influenzae and recurrent PBB are significant predictors. Clinicians should be cognizant of the relationship between PBB and bronchiectasis, and appropriate follow-up measures should be taken in those with risk factors.
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia; Murdoch Children's Research Institute, Melbourne, Australia. Electronic address: danielle.wurzel@mcri.edu.au.
authors.forename: Danielle F
authors.initials: DF
authors.lastname: Wurzel
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia; Queensland Children's Health Service, Brisbane, Australia.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Marchant
authors.affiliation: Queensland Lung Transplant Service, Prince Charles Hospital, Brisbane, Australia; School of Medicine, The University of Queensland, Brisbane, Australia.
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Yerkovich
authors.affiliation: School of Medicine, The University of Queensland, Brisbane, Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia; Queensland Children's Health Service, Brisbane, Australia.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Petsky
authors.affiliation: Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia; School of Medicine, Griffith University, Gold Coast, Australia.
authors.forename: Heidi
authors.initials: H
authors.lastname: Smith-Vaughan
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia; Queensland Children's Health Service, Brisbane, Australia.
authors.forename: Brent
authors.initials: B
authors.lastname: Masters
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Buntain
authors.affiliation: Queensland Children's Medical Research Institute, Brisbane, Australia; Queensland Children's Health Service, Brisbane, Australia; Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Chang
mesh_terms: D001424:Bacterial Infections / Q000382:microbiology*; D001987:Bronchiectasis / Q000382:microbiology*; D001991:Bronchitis / Q000382:microbiology*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011793:Queensland; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
keywords: bacterial infection; bronchiectasis; pediatric lung disease; respiratory infection; viral infection