602 Is it time to change the diagnostic criteria for bronchiectasis in children?

Objectives

There are significant delays between respiratory symptom onset and diagnosis of bronchiectasis via high-resolution CT (HRCT) scanning. Prompt control of infection and inflammation is key in halting disease progression and potentially reversing lung damage. Diagnosis of bronchiectasis is largely based on expert radiological opinion, emphasising the need for objective diagnostic criteria. Recent international guidelines suggest using broncho-arterial ratios (BAR) with a cut off of >0.8 in paediatrics rather than 1.0 used in adults; as adult ratios may underemphasize disease severity in children. Bronchial wall thickening, also a common finding in bronchiectasis, may be a potential alternative diagnostic marker.

Aims

To compare adult versus paediatric cut-off criteria of BAR in the diagnosis of bronchiectasis and to investigate whether bronchiectasis is reversible in childhood.

Methods

Retrospective analysis of 64 children with a diagnosis of bronchiectasis between 2009–2020 using electronic medical records at a tertiary children’s hospital. 96 HRCTs were reviewed for signs of bronchiectasis by 3 radiologists assessing inter- and intra-rater reliability agreement. BAR measurements were undertaken by one paediatric radiologist blinded to the patients’ clinical status, using the largest BAR per scan in the analysis. Changes in BAR were assessed for those patients with multiple HRCT scans.

Results

The mean age at HRCT diagnosis was 5 years (SD 3.35 years) (30 boys, 34 girls). Inter-rater reliability agreement was poor with disagreement in 27% cases. 50/64 patients had volumetric CT scans and were included in the analysis. 19/50 (38%) patients met adult radiological criteria for bronchiectasis (BAR≥1). 24/50 (48%) additional patients were labelled with a diagnosis of bronchiectasis using BAR≥0.8. 17 patients had repeat HRCT scans. of these, 10/17 (59%) demonstrated reduced BARs at follow up scan. The mean BAR reduction was 0.301 (SD0.147) with complete resolution of bronchiectasis in 8/10 cases.There was a significant difference in the mean wall thickening ratio (WTR) between patients with BAR>1 (0.627(0.237)) and BAR<1(0.455(0.09612), p=0.001).

Conclusions

BARs can act as more objective markers of bronchiectasis and to assess disease progression; WTR may provide an alternative or additional diagnostic marker. There remains a critical need to gain an evidence-base for paediatric-based cut-off BAR values to diagnosis bronchiectasis given significant life-long implication of this label. Bronchiectasis can be reversible in some children, and efforts should be made to promote early diagnosis via objective radiological markers, awareness of contributing factors, adequate investigations and early treatment and referral to tertiary services to limit disease progression and aid potentially reversal.

References

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