Persistent bacterial bronchitis in adults – a precursor to Bronchiectasis?

Abstract

Introduction: Bronchiectasis is a radiological diagnosis and a clinical syndrome. In children, a pre-bronchiectasis condition called persistent bacterial bronchitis (PBB) has been described but this is not recognised in adults. Here we describe a series of adult patients with clinical features of bronchiectasis without radiological bronchial dilation. Methods: CT scans from patients with clinically suspected bronchiectasis were reviewed and maximal bronchial-arterial ratio measured by two blinded observers. Fleischner society guidelines were used to diagnose radiological bronchiectasis. Adult PBB was defined by chronic or recurrent productive cough, laboratory evidence of bacterial infection in sputum cultures, responsiveness of cough to antibiotic treatment and exclusion of alternative causes of cough (asthma, smoking), with no overt bronchiectasis on CT. Results: 90 patients met the criteria for adult PBB, 56.7% female, mean age 67. 63 (70%) had positive sputum cultures at presentation. Of those with recurrent positive sputum samples, 68.9% had persistent Haemophilus influenzae infection. Pseudomonas aeruginosa was isolated in 7 patients. Applying the bronchiectasis severity index, the mean score was 7, indicating a significant burden of disease despite no radiological abnormality. 55 patients were treated with long term antibiotics, 42 had a documented reduction in exacerbation frequency and/or symptoms. 35 patients had follow-up CT scans of which 10 (28.6%) patients developed overt radiological bronchiectasis. Conclusion: Adult PBB is a distinct disease entity representing a precursor to overt bronchiectasis in some patients.