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Bronchiectasis

A condition marked by chronic abnormal dilation of bronchi and destruction of bronchial walls, bronchiectasis can occur throughout the tracheobronchial tree or can be confined to one segment or lobe. However, it's usually bilateral and involves the basilar segments of the lower lobes. This disease has three forms: cylindrical (fusiform), varicose, and saccular (cystic).

It affects people of both sexes and all ages. Because of the availability of antibiotics to treat acute respiratory tract infections, the incidence of bronchiectasis has dramatically decreased in the past 20 years. Its incidence is highestamong the Inuit of the Arctic and the Maoris of New Zealand. Bronchiectasis is irreversible once established

Causes

The different forms of bronchiectasis may occur separately or simultaneously. In cylindrical bronchiectasis, the bronchi expand unevenly, with little change in diameter, and end suddenly in a squared-off fashion. In varicose bronchiectasis, abnormal, irregular dilation and narrowing of the bronchi give the appearance of varicose veins. In saccular bronchiectasis, many large dilations end in sacs.

This disease results from conditions associated with repeated damage to bronchial walls and abnormal mucociliary clearance, which cause a breakdown of supporting tissue adjacent to airways. Such conditions include: . mucoviscidosis (cystic fibrosis)

• immunologic disorders (agammaglobulinemia, for example).
• recurrent, inadequately treated bacterial respiratory tract infections, such as tuberculosis, and complications of measles, pneumonia, pertussis, or influenza.
• obstruction (by a foreign body, tumor, or stenosis) in association with recurrent infection.
• inhalation of corrosive gas or repeated aspiration of gastric juices into the lungs.
• congenital anomalies (uncommon), such as bronchomalacia, congenital bronchiectasis, immotilecilia syndrome (ICS), and Kartagener's syndrome, a variant of ICS characterized by situs inversus, bronchiectasis, and either nasal polyps or sinusitis.
• In bronchiectasis, hyperplastic squamous epithelium denuded of cilia replaces ulcerated columnar epithelium. Abscess formation involving all layers of the bronchial wall produces inflammatory cells and fibrous tissue, resulting in both dilation and narrowing of the airways. Mucus or fibrous tissue obliterates smaller bronchioles, while peribronchial lymphoid tissue becomes hyperplastic. Extensive vascular proliferation of bronchial circulation occurs and produces frequent hemoptysis.

Signs and symptoms

Initially, bronchiectasis may be asymptomatic. When symptoms do arise, they're often attributed to other illnesses. The patient usually complains of frequent bouts of pneumonia or hemoptysis. The classic symptom, however, is a chronic cough that produces copious, foul-smelling, mucopurulent secretions, possibly totaling several cupfuls daily. Characteristic findings include coarse crackles during inspiration over involved lobes or segments, occasional wheezes, dyspnea, sinusitis, weight loss, anemia, malaise, clubbing, recurrent fever, chills, and other signs of infection. Advanced bronchiectasis may produce chronic malnutrition and amyloidosis as well as rightsided heart failure and cor pulmonale due to hypoxic pulmonary vasoconstriction.

Diagnosis

Chest x ray may reveal evidence of bronchiectasis, and CT scans are particularly good at revealing the thick, dilated bronchial walls of bronchiectasis. Sputum will need to be collected and cultured (grown in a laboratory dish), in order to examine it microscopically for the specific type of organism responsible for infection. A careful search for other underlying diseases is important, looking in particular for ciliary abnormalities, cystic fibrosis, or immunoglobulin deficiencies.

Treatment

Typically, antibiotics are given orally or I V. for 7 to 10 days or until sputum production decreases. Bronchodilators, combined with postural drainage and chest percussion, help remove secretions if the patient has bronchospasm and thick, tenacious sputum. Bronchoscopy may be used to help mobilize secretions.

Hypoxia requires oxygen therapy;severe hemoptysis often requires lobectomy, segmental resection, or bronchial artery embolization if pulmonary function is poor.

In some patients, bronchiectasis eventually leads to a constantly low level of blood oxygen, despite other treatments. These patients usually have an associated increase in the size of the right side of their hearts, along with a decrease in the heart's ability to pump blood through the lungs. Some patients with extremely severe symptoms and disability have been treated with lung transplantation .

Prevention

The risk may be reduced if lung infections are promptly treated.