Clinical Scenario

A twenty-nine year old female non-smoker presents to her general practitioner with a cough, producing large volumes of purulent sputum. She has had several of these episodes over the years, but believes this is due to working in a nursery, as many of the children have "coughs and colds."

What is the differential diagnosis?

  • Tracheobronchial infection
  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Rhinosinus disease
  • Gastro-oesophageal reflux disease

What other questions should be asked?

A full history should be ascertained, addressing areas such as past medical history, drug history and recent foreign travel. A respiratory history should be taken, paying particular attention to the following symptoms:

 

  • Chronic cough with purulent sputum
  • Chronic respiratory symptoms such as breathlessness and wheezing
  • Haemoptysis
  • Chest pain - may be pleuritic in origin

 

    In addition to the chronic cough with the production of purulent sputum, the patient also admitted episodes of pleuritic chest pain and an episode of haemoptysis. Auscultation of her chest revealed crackles and wheeze. As she had already been on courses of antibiotics, the GP sent off a sputum culture and referred her to a chest physician.

    How would you further investigate this?

    The role of investigations in bronchiectasis are to ascertain the cause and assess the severity of the disease. The following investigations are considered appropriate according to the British Thoracic Society:

    • Baseline chest x-ray
    • High resolution CT is the radiological investigation of choice. Radiological evidence of bronchiestasis includes bronchial wall dilatation and thickening.
    • Serum immunoglobulins (IgG, IgA, IgM) and electrophoresis
    • Serum IgE or skin prick testing
    • Sputum microbiology
    • All children and adults under the age of forty years of age, should be tested for cystic fibrosis.
    • Investigations of ciliary function in children.
    • Patients with local features of bronchiectasis should undergo bronchoscopy to look for evidence of a foreign body or proximal airway obstruction

     

      The patient's sputum culture grew Pseudomonas aeruginosa. Given this unusual organism, the chest physician requires a high-resolution CT scan, which demonstrated areas of bronchial wall thickening and dilatation, giving a diagnosis of bronchiectasis. Other investigations, such as immunoglobulins and CFTR status, were normal.

        High-resolution CT scan demonstrating bronchiectasis

        What is bronchiectasis?

        Bronchiectasis can be defined as an irreversible dilatation of the bronchi caused by destruction of the muscular and elastic tissue of the bronchial walls [Rubin R, Strayer DS. Rubin's Pathology]. It was once much more common, usually resulting from childhood respiratory infections, but vaccination and antibiotic therapy have reduced the prevalence.

        What are the causative factors?

        Bronchiectasis has several different causes, which includes the following:

        • Idiopathic
        • Infection: measles, pertussis, adenovirus, aspergillus
        • Cystic fibrosis
        • Obstruction by a tumour, foreign body or enlarged hilar lymph node
        • Disorders of ciliary motility
        • Neurological disorders which impair swallowing and the cough reflex
        • Immunodeficiency, especially in children.

        The pathogenesis of bronchiectasis is complex and several different mechanisms have been proposed. A "vicious circle" of events is most likely to take place, involving damage to the bronchial epithelium which allows colonisation by bacteria leading to impaired ciliary clearance and subsequent inflammation. Some of the bacteria known to do this are Haemophilus influenzae, Streptococcus pneumoniae and Pseudomonas aeruginosa. 

        Due to the prolonged and repeated bouts of inflammation, there is weakening of the bronchial walls, due to proteolytic enzymes and reactive oxygen species (ROS) released from neutrophils, leading to dilatation. 

        What are the complications?

        The right-sided lung demonstrates bronchiectasis

        On gross inspection, the bronchi are dilated and have thickened walls, with collapse of the distal lung. The lumen frequently contain think, purulent secretions. Histologically, there is severe inflammation, leading to destruction of all layers of the bronchial walls. The bronchial arteries are enlarged to meet the additional vascular requirements to sustain the inflammation and fibrosis.

        Complications include the development of a lung abscess and empyema

        How should this be managed?

        Patients with bronchiectasis need to be managed by a multi-disciplinary team involving communication between the general practitioner, chest physician, microbiologist, physiotherapy and primary care nurses. The management according to the British Thoracic Society includes: 

        • The patient should be taught airway clearing techniques and exercises by the chest physiotherapist. 
        • All patients should receive their annual influenza and pneumococcal vaccinations.
        • β2-agonist and anti-cholinergic bronchodilators in patients with an element of reversibility in their airflow obstruction, demonstrated by pulmonary function tests.
        • The patient should undergo pulmonary function testing annually (at least).
        • Antibiotics should be given for exacerbations which cause worsening symptoms.
        • Non-invasive ventilation may be used in patients with chronic respiratory failure to improve quality of life.
        • Lung resection surgery may be used in patients whose symptoms cannot be controlled by pharmacological means alone.

        Summary

        • Aetiology: Multiple factors can predipose people to bronchiectasis including infection, obstruction of the bronchi, ciliary dyskinesia, immunodeficiency and cystic fibrosis. Damage to the bronchial epithelium encourages colonisation by bacteria, leading to an inflammatory response causing damage to the bronchial walls.
        • Clinical features: Chronic cough with the production of purulent sputum, sometimes associated with pleuritic chest pain and haemoptysis. 
        • Pathology: The inflammation leads to destruction of the bronchial walls and subsequent dilatation. There is collapse of the lung distal to the affected bronchi.
        • Investigations: High resolution CT scan is the gold standard. Other tests include sputum microbiology and immunglobulin studies. Bronchoscopy, ciliary function tests and CFTR status where appropriate.
        • Management: Multi-disciplinary management. Patient should be taught airway clearing techniques by physiotherapy and bronchodilators should be given if there is a reversible element of the obstruction. Antibiotics should be given in exacerbations. Surgery and NIV may be appropriate in some cases.

        References

        Adler KB, Hendley DD, Davis GS. Bacteria associated with obstructive pulmonary disease elaborate extracellular products that stimulate mucus secretion by explants of guinea pig airways. Am J Path 1986;125:501-514

        Cole P, Wilson R. Host-microbial interrelationships in respiratory infection. Chest. 1989;95:217S-221S. 

        King P. Pathogenesis of bronchiectasis. Paediatric Respiratory Reviews 2010 12;2: 104-110

        King PT, Holdsworth SR, Freezer NJ, Villaneuva E, Holmes PW. Characteristication of the onset and presenting clinical features of adult bronchiectasis. Respiratory Medicine 2006;100:12 2183-2189

        Nicotra MB, Rivera M, Dale AM, Shepherd R, Carter R. Clinical, pathophysiologic, and microbiologic characterization of bronchiectasis in an aging cohort. Chest1995;108:955-61 

        Pasteur MC, Bilton D, Hill AT. BTS Guidelines for non-CF bronchiectasis [online]. British Thoracic Society. Cited: March 15th 2012. Available from URL: http://www.brit-thoracic.org.uk/Portals/0/Clinical%20Information/Bronchiectasis/BronchiectasisQFG_web.pdf

        ten Hacken NHT, van der Molen T. Easily missed? Bronchiectasis. BMJ 2010;341:c2766

        Corrin B. Pathology of the Lungs. 1st Edition. Churchill Livingstone. China. 2000 pages 84-87

        Rubin R, Stayer DS. Rubin's Pathology. Clinicopathological Foundations of Medicine. 5th Edition. Lippincott, Williams & Wilkins. China. 2008 page 490

        The case scenario was adapted from ten Hacken NHT, van der Molen T, Easily missed? Bronchiectasis. BMJ 2010;341:c2766

        Figure 2: taken from The Newcastle upon Tyne Hospitals. Cardiothoracic Services [online]. 15th March 2012. Available from URL: http://www.newcastle-hospitals.org.uk/services/cardiothoracic_services_bronchiectasis.aspx 

        Figure 3: taken from Pitney AC, Callahan CW, Reuss L. Reversal of bronchiectasis caused by chronic aspiration in cri du chat syndrome. Images in paediatric medicine 2001;84: 413-414

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