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122 Chapter 3: Respiratory system

Appropriate vaccination against influenza, H. in- thickened and permanently dilated. The lower lobes of

fluenzae Strep pneumoniae, measles, pertussis and the lungs tend to be most affected because of gravita-
varicella. tional pooling of secretions.
Gene therapy is currently being researched in an

attempt to ‘infect’ individuals with a retrovirus car- Clinical features
rying the normal CF gene. In mild cases sputum production only occurs post-
3 Surgical treatment: If the patient has a life expectancy infection. More severely affected patients have chronic
of less than 18 months, lung (or heart–lung) trans- halitosis, a cough with copious thick sputum, recurrent
plantation is used with good result. Liver transplan- fevers and episodes of pneumonia. Patients may be dys-
tation has been used in patients with end-stage liver pnoeic, clubbed and cyanosed. Haemoptysis may occur
disease. due to friable granulation tissue and can be massive.
Coarse crackles and sometimes wheeze (due to airflow
Prognosis limitation) are heard over affected areas.
Median age of survival is 31 years but is expected to rise
with improving therapies. Macroscopy
Largedilatedairspacesareseenextendingouttothelung
periphery.
Bronchiectasis
Definition Microscopy
Bronchiectasis is a condition characterised by purulent Chronic inflammation in the wall of the abnormal
sputum production with cystic dilation of the bronchi. bronchiwithreplacementoftheepitheliumwithinflam-
matory granulation tissue, which bleeds. There may be
Aetiology squamous metaplasia of the bronchial mucosa.
In developed countries, cystic fibrosis is the most com-
mon cause, tuberculosis and post-childhood infections Complications
are also common. Pneumonia.
1 Changes in the normal drainage of bronchial secre- Pneumothorax, empyema.
tions: Chronic cases may lead to respiratory failure and cor
Airway obstruction such as by a tumour or foreign pulmonale.

body. Chronic suppuration causes abscess formation,
The mucus may not drain if it is excessively thick as haematogenous spread of infection (formation of

in cystic fibrosis. cerebral abscesses) and development of amyloidosis.
Conditions affecting cilia such as ciliary dyskine-

sia and Kartagener’s syndrome (genetic syndrome Investigations
associated with dextrocardia and situs inversus). Chest X-ray may be normal or may show the dilated
2 Infections causing damage to the bronchial walls: thick walled bronchi.
Childhood respiratory infection in the developing High resolution CT scans are diagnostic showing the

lung, e.g. measles, whooping cough and pneumo- dilated bronchi with thickened walls and adjacent
nia. artery forming the typical signet ring appearance.
Persistent infections such as tuberculosis, allergic Sputum culture is necessary to treat infections. The

bronchopulmonary aspergillosis. most common organisms are Staph. aureus, Pseu-
Immunodeficiency states resulting in recurrent in- domonas aeruginosa, H. influenzae and anaerobes.

fections. Serum immunoglobulins, sweat test, cilial motility
studies where indicated.
Pathophysiology
Impairment of the mucociliary transport mechanism Management
leads to recurrent infections, which leads to further ac- The aim is to prevent chronic sepsis and reduce acute
cumulation of mucus. Bronchial walls become inflamed, infections.