BRONCHIECTASIS is a condition of permanent abnormal dilatation of the larger bronchi.
AETIOLOGY AND PATHOGENESIS
Obstruction of a bronchial segment (small bronchi) results is atelectatis of the lung distal to the obstruction and to compensate the negative pressure which results therefrom, surraunding bronchioles dilate.
The usual causes of obstruction are mucous plugs, fragment of blood clot, infected tissues, etc., which usually contain bacteria. Bacterial infection leads to formation of granulation tissues and weakness of the bronchial wall.
The above factors are usual causes of bronchiectasis and operate in the following conditions:
Foreign body and bronchial adenoma.
Tuberculosis: Apart from tuberculous bronchiectasis which may occur anywhere in the affected portion of the lung there may be middle lobe syndrome (Brock’s syndrome). Middle lobe bronchiectasis is caused by obstruction of middle lobe bronchus by tuberculous lumph node.
Allergic bronchopulmonary aspergillosis
Whooping cough, measles.
Other Gram negative infections.
Abnormal lung defence mechanism as in normal and immunodeficiency, alphal antiprotease deficiency.
Immunodeficiency states: Acquired panhypogamma globulinamia, common variable immunodeficiency, selective IgA, IgM and IgG subclass deficiencies, acquired immunodeficiency from cytotoxic therapy, AIDS, lymphoma, multiple myeloma, leukaemia chronic renal and hepatic disorders.
In case of Young’s syndrome (obstructive azospermia and broncho-pulmonary infection) and yellow nail syndrome (lymphoedema of lower limbs, recurrent pneumonia, bronchiectasis and yellow discolouration of nails) which are very rare disorders.
In some cases there may be congenital maldevelopment of the bronchi, inappropriate clearance of bronchioles, Immotile cilia syndrome with or without recurrent infection. These are seen in cases of Kartagener’s syndrome (dextrocardia, situs inversus, bronchiectasis, sinusitis and infertility), Cystic fibrosis and Congenital hypogamma-globulinaemia.
The bronchial dilatations are usually of four types -saccular or globular, fusiform or pyriform, cylindrical, rat tail or tubular, moniliform or bead like. The bronchiectatic cavities are more frequently formed in lower lobes (50%) because of inadequate drainage and also due to the effect of gravity. Left lung is more affected than the right. Common sites are lower lobes, lingual and middle lobe. Lining membrane is formed by granulation tissue depending on the degree of infection. Inflammatory changes are found in deeper layers of bronchial wall.
Surrounding lung tissue may be fibrosed. Wide spread anastomoses are established between bronchial and pulmonary arterioles.
Onset is insidious.
Cough with expectoration
This is the most important symptom of bronchiectasis and is present for a long time. This is related to change of posture and thus becomes prominent in the early hours of the morning when the patient wakes up from bed or at the time of retiring to bed. Sputum is always copious in amount and purulent in nature. It may have a foetid odour from time to time due to infection by oral saprophytic organisms. In the “dry” type of bronchiectasis (bronchiectasis sicca), this symptom is absent.
This varies in amount from slight blood-tinged sputum to frank haemorrhage. It is due to bleeding from the bronchiectatic cavities which are lined by granulation tissue or from vascular anastomoses. In the “dry” type of bronchiectasis this is the only symptom.
This may occur recurrently and is due to dry pleurisy or pneumonia which occurs in association with infection of the bronchiectatic cavities.
Regurrent Pneumonia and Pleurisy
This is due to secondary infection of the bronchiectatic cavities and thus recurs from time to time. This may last for few days or weeks and may come with chill and rigour and goes away with sweating indicating pent up pus in the cavities.
It is present in about 70% of the cases.
This is usually due to pneumonia or due to chronic bronchitis.
Malaise, loss of weight may occur but rare.
Clubbing is usually present and is due to suppuration in about 50% of the cases. Pulmonary osteoarthropathy may also develop, weight loss and febrile episodes are present.
Shows no finding if the bronchiectatic cavities are dry and there is no pulmonary fibrosis, atelectasis or effusion. When considerable amount of pulmonary fibrosis is present together with exudates in the bronchiectatic cavity, expansion of the chest is diminished, vocal fremitus is diminished, percussion shows impaired resonance, breath sound is diminished (or bronchial in type if the exudates are less), vocal resonance is diminished and plenty of leathery or fibroid rales are present. These findings are usually basal and bilateral. Signs of consolidation, collapse and chronic pleurisy may also be present.
Blood shows leucocytosis with increased polymorphs in presence of recent infection.
Sputum shows Haemophilus influenzae, sometimes E. coli, proteus and pseudomonas. Staph. aureus iS found in cystic fibfosis. When collected in a conical flask, sputum shows three layers as in lung abscess. But elastic tissues are absent and only pus cells are present. The upper layer contains froth, the middle layer contains heavier particles e.g., epithelial debris, bacterial masses, foul-smelling Dettrich’s plugs.
Radiological (see figs. 2.4, 2.5, 2.6, 2.7).
a) X-ray of the chest is usually normal, sometimes thickening of basal pleura and “Birds’ nest or honeycomb appearance of the basal portion of the lung may be seen. There may be crowded lung markings, related to thickening of bronchial mucosa.
b) Bronchogram will usually reveal the dilated bronchi and this is confirmative.
c) Thin section CT scan may also locate the site of lesion.) High resolution CT scan is emerging as the diagnostic test of choice in cases of bronchiectasis.
Bronchoscopy may be done in children to find out foreign body; in cases of bronchial adenoma and to rule out obstructive airway lesion. This is also required to evaluate the cause of haemoptysis.
Lung function tests may show depressed function due to hyperinflation or fibrosis of lung.
Other special tests for diagnosis of the original diseases should also be carried out.
Constitutional symptoms are more marked, signs are unilateral and chest X-ray or CT scan finally reveals the lesion.
Long history of cough with mucoid expectoration, generalized bilateral moist sound and rhonchi may be present. Clubbing if present is of “Parrot’s beak” type and not drum stick type. Bronehogram will not reveal any dilatation.
Anorexia, rapid loss of weight will be present, clubbing is absent and findings are apical rather than basal. X-ray of the chest and positive sputum for AFB are corroborative findings.
Recurrent pleurisy with or without effusion.
Chronic cor pulmonale.
Acute benign pericarditis.
Postural drainage: This depends on the site of the lesion. When the disease is located in the lower lobes, the patient lies on the edge of the bed with his hands on the floor and in this position coughs several times and this may drain the cavity by the effect of gravity. This is to be continued for about 20 minutes in an empty stomach once or twice daily. Bronchoscopic aspiration may be required if the communicating bronchus is blocked by thick sputum or by foreign body.
Antibiotics: This is chosen according to the sensitivity of the organism after sputum culture and sensitivity test. Azithromycin 500 mgm thrice a week is a good effective prophylactic which may be used. During acute exacerbation other antibiotics as mentioned in chronic bronchitis may also be used. Alternately a combination of Trimethoprim sulphamethoxazole may also be given.
If the disease is limited to any one part of a lung as judged by bronchogram or CT scan, lobectomy or pneumonectomy may be done, provided the patient is below 40 years having persistent troublesome symptoms. Surgery is also indicated in massive haemoptysis.
Chronic bronchitis, bronchospasm, sinusitis and respiratory failure should also be treated accordingly.
General treatment: Good nutritious food and polyvitamins are given. Anaemia can be corrected. Chronic septic foci in the upper respiratory tract should also be treated.