Protracted bacterial bronchitis: more to know

Protracted bacterial bronchitis (PBB) is defined based on several parameters: (1) wet cough > 4 weeks, (2) improvement of cough within two weeks of antibiotic therapy, and (3) no signs or symptoms due to other underlying etiologies of chronic cough (“cough pointers”). PBB usually affects predominantly children aged <6 years old and male. The aetiology of PBB remains unknown. Predisposing factors include tracheobronchomalacia, positive bronchoalveolar lavage (BAL) culture for Haemophilus influenzae, Streptococcus pneumoniae, or Moraxella catarrhalis. Patients affected by PBB typically have wet coughs, especially upon awakening and during exercise. Thoracic objectivity is negative, and the children’s general conditions are good. Therefore, a diagnostic approach for chronic cough should be oriented according to clinical history; a chest X-ray must be obtained, and spirometry must always be performed. The results of these two tests are usually normal, although a chest X-ray may sometimes show peri-bronchial infiltrates, a common and non-specific finding in childhood. Moreover, in the absence of specific “cough pointers” and when PBB is suspected, a sputum culture must always be obtained before starting antibiotic treatment. A positive result strengthens the diagnosis, although it has a low specificity. If “cough pointers” are present or PBB is suspected, antibiotic therapy is ineffective, and a recurrence of symptoms is observed, other etiologies of chronic cough should be investigated. PBB can lead to chronic pulmonary suppurative disease and bronchiectasis if left untreated. PBB and bronchiectasis share common features; however, it remains to be determined whether inflammation and colonization are the cause or an infection-induced effect. PBB treatment is based on antibiotics which are usually amoxicillin-clavulanate, for two weeks, up to a maximum of four according to the clinical course.