Bronchiolitis remains the most common acute lower respiratory tract infection (ALRTI) in infants. Respiratory Syncytial Virus (RSV) is the most common virus detected in bronchiolitis, although other viruses may also contribute. Bronchiolitis causes inflammation of the small airways, increasing mucous production and necrosis of epithelial tissue. Bronchiolitis is a clinical diagnosis characterised by tachypnoea, wheeze and/or crepitations in infants following a preceding upper respiratory illness. Most cases can be treated at home; however in some cases hospitalisation may be required for supportive therapy (such as oxygen and fluid therapy). We have found that Northern Territory (NT) Indigenous infants present to hospital more often with more severe bronchiolitis than non Indigenous infants. These infants are at greater risk of developing longer term respiratory problems including chronic suppurative lung disease or bronchiectasis. Bronchiolitis in NT Indigenous children is complicated by the known early colonisation of the nasopharynx by bacterial pathogens, notably Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae. A class of antibiotics called macrolides like Azithromycin have been widely used in the NT for bronchiectasis, trachoma and sexually transmitted diseases for more than 10 years. Azithromycin has anti inflammatory and bacterial properties. It has a longer half life and better tissue penetration than other macrolides thus requiring a much shorter treatment regime. Once weekly dosing has been shown to be sufficient for tissue effects lasting over a week. Any intervention that is efficacious in reducing the severity of bronchiolitis and or readmission for bronchiolitis in particular for Indigenous children would be beneficial in both short and long term outcomes.

Aim/goal of project

Hypothesis
This double blinded placebo-controlled randomized controlled trial was to assess the efficacy of a single dose of Azithromycin (30mg/kg) in 92 infants ≤18 months admitted to Royal Darwin Hospital and The Townsville Hospital to

a) Improve the clinical course of moderate to severe bronchiolitis (assessed by supplemented oxygen requirement and length of hospital stay)
b) Reduce the risk of further respiratory illness within 6 months of this bronchiolitis episode.
c) Profile the immunopathology of bronchiolitis in the presence and absence of co-existing respiratory infections.

We completed enrolment in 2011 and are in the process of disseminating results to families and key stakeholders. Results for the public will be available, once the study has been published. 

Respiratory resources
www.lunginfonet.edu.au