title: Wet cough in children: infective and inflammatory characteristics in broncho-alveolar lavage fluid.
abstract: Wet cough is a common feature of many disease processes affecting children. Our aim was to examine the relationships between cough nature, lower airway infection (bacterial, viral, and viral-bacterial) and severity of neutrophilic airway inflammation. We hypothesized that viral-bacterial co-infection of the lower airway would be associated with wet cough and heightened neutrophilic airway inflammation. We prospectively recruited 232 children undergoing elective flexible bronchoscopy. Participants were grouped using a cough nature symptom-based approach, into wet, dry or no cough groups. Broncho-alveolar lavage (BAL) and clinical data, including presence, nature, and duration of cough and key demographic factors, were collected. Children with wet cough (n = 143) were more likely to have lower airway bacterial infection (OR 2.6, P = 0.001), viral infection (OR 2.04, P = 0.045) and viral-bacterial co-infection (OR 2.65, P = 0.042) compared to those without wet cough. Wet cough was associated with heightened airway neutrophilia (median 19%) as compared to dry or no cough. Viral-bacterial co-infection was associated with the highest median %neutrophils (33.5%) compared to bacteria only, virus/es only and no infection (20%, 18%, and 6%, respectively, P < 0.0001). Children with wet cough had higher rates of lower airway infection with bacteria and viruses. Maximal neutrophilic airway inflammation was seen in those with viral-bacterial co-infection. Cough nature may be a useful indicator of infection and inflammation of the lower airways in children.
authors.affiliation: Queensland Children's Medical Research Institute, The University of Queensland, Royal Children's Hospital, Brisbane, Queensland, Australia; Queensland Children's Respiratory Centre, Royal Children's Hospital, Brisbane, Queensland, Australia.
authors.forename: Danielle F
authors.initials: DF
authors.lastname: Wurzel
authors.forename: Julie M
authors.initials: JM
authors.lastname: Marchant
authors.forename: Julia E
authors.initials: JE
authors.lastname: Clark
authors.forename: I Brent
authors.initials: IB
authors.lastname: Masters
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Yerkovich
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
authors.forename: Anne B
authors.initials: AB
authors.lastname: Chang
mesh_terms: D001424:Bacterial Infections / Q000175:diagnosis*; D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D001999:Bronchoscopy; D002675:Child, Preschool; D060085:Coinfection; D003371:Cough / Q000209:etiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009504:Neutrophils / Q000473:pathology; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000175:diagnosis*; D014777:Virus Diseases / Q000175:diagnosis*
keywords: airway inflammation; bacterial infections; bronchitis; co-infection; respiratory tract; viral infections