Protracted bacterial bronchitis

Last revised by Henry Knipe on 6 Oct 2022

Protracted bacterial bronchitis is one of the most common causes of cough in children, particularly those aged <6 years. Is it characterized by a chronic wet cough with no associated cause and tends to respond to 2 weeks of antibiotic therapy.

Protracted bacterial bronchitis is the most common cause of cough in childhood and is 2-3 times more common than asthma 1.

Most children are unable to produce sputum. In the minority of cases where further investigation is performed in the form of bronchoscopy, bronchoalveolar lavage reveals neutrophil infiltration with large numbers of respiratory bacterial pathogens, e.g. Haemophilus influenzae 1.

A variety of diagnostic criteria have been used. The original criteria required confirmation of lower airway infection. The modified criteria are clinical only.

Diagnostic criteria 1:

  • original (micro)

    • wet-cough >4 weeks

    • lower airway infection (confirmed from sputum or BAL)

    • cough resolved following 2-week course of antibiotics

  • modified (clinical)

    • wet-cough >4 weeks

    • absence of symptoms or signs of another cause

    • cough resolved following 2 week course of antibiotics

There is also an extended form of protracted bacterial bronchitis which is defined as taking over 4 weeks to respond to antibiotics.

Recurrent protracted bacterial bronchitis is defined when there are more than 3 episodes in a year.

Radiology involvement is usually not required. Some children will have a chest x-ray as part of the clinical diagnostic criteria to ensure the absence of anything else causing a chronic wet cough.

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