Bronchiectasis

Bronchiectasis means abnormal dilatation of the bronchi.

Chronic suppurative airway infection with sputum production, progressive scarring and lung damage are present, whatever the cause.

Congenital defect affecting airway ion transport or ciliary function, such as cystic fibrosis .

Acquired secondary to damage to the airways by a destructive infection, inhaled toxin or foreign body. The result is chronic inflammation ,tuberculosis is the most common world-wide.

Localised bronchiectasis may occur due to the accumulation of pus beyond an obstructing bronchial lesion, such as enlarged tuberculous hilar lymph nodes, a bronchial tumour or an inhaled foreign body (e.g. an aspirated peanut).

Aetiology and pathogenesis Bronchiectasis

The bronchiectatic cavities may be lined by granulation tissue, squamous epithelium or normal ciliated epithelium.

Chronic inflammatory and fibrotic changes are usually found in the surrounding lung tissue, resulting in progressive destruction of the normal lung architecture in advanced case

Pathology

Physical signs in the chest may be unilateral or bilateral. If the bronchiectatic airways do not contain secretions and there is no associated lobar collapse, there are no abnormal physical signs.

When there are large amounts of sputum in the bronchiectatic spaces, numerous coarse crackles may be heard over the affected areas.

Acute haemoptysis is an important complication of bronchiectasis; management is covered on page

Clinical features and symptoms of bronchiectasis(table)

In addition to common respiratory pathogens, sputum culture may reveal Pseudomonas aeruginosa, fungi such as Aspergillus and various mycobacteria..

This time should not exceed 20 minutes but is greatly prolonged in patients with ciliary dysfunction.

Ciliary beat frequency may also be assessed using biopsies taken from the nose. Structural abnormalities of cilia can be detected by electron microscopy.

Investigations Bacteriological and mycological examination of sputum

In airflow obstruction, inhaled bronchodilators and corticosteroids should be used to enhance airway patency.

Physiotherapy Patients should be instructed on how to perform regular daily physiotherapy to assist the drainage of excess bronchial secretions. Patients should adopt a position in which the lobe to be drained is uppermost.

Deep breathing followed by forced expiratory (the 'active cycle of breathing' technique) is of help in moving secretions in the dilated bronchi towards the trachea, from which they can be cleared by vigorous coughing.

'Percussion' of the chest wall with cupped hands may help to dislodge sputum, but does not suit all patients. .

The optimum duration and frequency of physiotherapy depend on the amount of sputum, but 5-10 minutes once or twice daily is a minimum for most patients.

Management

Antibiotic therapy in general, require larger doses and longer courses .

When secondary infection occurs with staphylococci and Gram-negative bacilli, in particular Pseudomonas species, antibiotic therapy becomes more challenging and should be guided by the microbiological sensitivities.

For Pseudomonas, oral ciprofloxacin (250-750 mg 12-hourly) or ceftazidime by intravenous injection or infusion (1-2 g 8-hourly) may be required.

Haemoptysis in bronchiectasis often responds to treating the underlying infection, although in severe cases percutaneous embolisation of the bronchial circulation by an interventional radiologist may be necessary.

Surgical treatment Excision of bronchiectatic areas is only indicated in a small proportion of cases.

Management

Cystic fibrosis The most common fatal genetic disease in Caucasians, with autosomal recessive inheritance.CF is the result of mutations affecting a gene on the long arm of chromosome 7 which codes for a chloride channel known as cystic fibrosis transmembrane conductance regulator (CFTR), that influences salt and water movement across epithelial cell membranes. This lead to increased sodium and chloride content in sweat and increased resorption of sodium and water from respiratory epithelium. Relative dehydration of the airway epithelium is thought to predispose to chronic bacterial infection and ciliary dysfunction, leading to bronchiectasis. The gene defect also causes disorders in the gut epithelium, pancreas, liver and reproductive tract .

Clinical features The lungs are most commonly infected with Staphylococcus aureus; however, many patients become colonised with Pseudomonas aeruginosa by the time they reach adulthood. The upper lobes but subsequently throughout both lungs, cause progressive lung damage resulting ultimately in death from respiratory failure. Most men with CF are infertile due to failure of development of the vas deferens, but microsurgical sperm aspiration and in vitro fertilisation are now possible.

Complications of cystic fibrosisRespiratory :Infective exacerbations of bronchiectasis,Spontaneous pneumothorax,Haemoptysis,Nasal polyps,Respiratory failure,Cor pulmonale,Lobar collapse due to secretions .

Gastrointestinal: Malabsorption and steatorrhoea,Distal intestinal obstruction syndrome ,Biliary cirrhosis and portal hypertension,Gallstones

Others :Diabetes (25% of adults),Delayed puberty,Male infertility,Stress incontinence due to repeated forced cough ,Psychosocial problems,Osteoporosis,Arthropathy,Cutaneous vasculitis.

ManagementTreatment of CF lung disease : The management of CF lung disease is that of severe bronchiectasis. All patients with CF who produce sputum should perform regular chest physiotherapy, and should do so more frequently during exacerbations. While infections with Staph. aureus can often be managed with oral antibiotics, intravenous treatment (often self-administered at home through a subcutaneous vascular port) is usually needed for Pseudomonas species. Regular nebulised antibiotic therapy (colomycin or tobramycin) is used between exacerbations in an attempt to suppress chronic Pseudomonas infection. Treatments that may reduce chest exacerbations and/or improve lung function in CF 1) Nebulised recombinant human DNase 2.5 mg daily used in patient Age ≥ 5, FVC > 40% predicted 2) Nebulised tobramycin 300 mg 12-hourly, given in alternate months used in Patients colonised with pseudomonas aeruginosa 3)Regular oral azithromycin 500 mg three times/week used in Patients colonised with Pseudomonas aeruginosa .

Bronchi of many CF patients eventually become colonised with pathogens which are resistant to most antibiotics. Resistant strains of P. aeruginosa, Stenotrophomonas maltophilia and Burkholderia cepacia are the main culprits, and may require prolonged treatment with unusual combinations of antibiotics. Aspergillus and 'atypical mycobacteria' are also frequently found in the sputum of CF patients, but in most cases these behave as benign 'colonisers' of the bronchiectatic airways and do not require specific therapy. Some patients have coexistent asthma, which is treated with inhaled bronchodilators and corticosteroids; allergic bronchopulmonary aspergillosis also occurs occasionally in CF. For advanced CF lung disease, home oxygen and NIV may be necessary to treat respiratory failure. Ultimately, lung transplantation can produce dramatic improvements but is limited by donor organ availability.

Management

Treatment of non-respiratory manifestations of CF

Malabsorption is treated with oral pancreatic enzyme supplements and vitamins. The increased calorie requirements of CF patients are met by supplemental feeding, including nasogastric or gastrostomy tube feeding if required. Diabetes eventually appears in over 25% of patients and often requires insulin therapy. Osteoporosis secondary to malabsorption and chronic ill health should be sought and treated.

Somatic gene therapy : The discovery of the CF gene and the fact that the lethal defect is located in the respiratory epithelium (which is accessible by inhaled therapy) presents an exciting opportunity for gene therapy. Manufactured normal CF gene can be 'packaged' within a viral or liposome vector and delivered to the respiratory epithelium to correct the genetic defect.