Bronchiectasis: It is an abnormal dilatation of the segmental and subsegmental bronchi associated with recurrent infections.

Causes of bronchiectasis:

Infections

	Bacterial pneumonia
	Pertussis causing tracheobronchitis
	Adenovirus pneumonia
	Measles pneumonia
	Endobronchial tuberculosis

Pathogenesis:

It is usually the consequence of airway obstruction or inflammation in response to chronic or repeated infections. Reid has classified it into 3 types: cylindrical, varicose and saccular (or cystic).

	Cylindrical bronchiectasis – The bronchial outlines are regular and diffusely dilated, the distal portion of involved airway terminates abruptly because of plugging of the smaller airways by mucus. To some extent, cylindrical bronchiectasis is reversible.
	Varicose bronchiectasis –Focal constrictions and sacculations occur.
	Saccular (cystic) bronchiectasis – Cystic dilation of affected airway increases towards the periphery and ballooning of the bronchus may occur.

Pathology: Affected bronchial segments are pliant and distorted due to destruction of muscular and elastic components of the airway walls. Dilation is due to atelectasis caused by accumulation of purulent secretions and obstruction of the peripheral airway with internal digestion of structural proteins of the airway due to lytic enzymes released from neutrophils in the purulent material in the airway and also by traction on the airway. Chronic inflammation leads to destruction of bronchial cartilage and pulmonary fibrosis with damage to peribronchial alveoli. Anastomosis form between pulmonary and bronchial vessels and along with alveolar hypoxia may lead to cor pulmonale.

Clinical Features: Patients present with failure to thrive, fever, chronic productive cough and recurrent pulmonary infections. Hypoxemia is mild. Leathery coarse crepitations may be heard over the affected region. Hemoptysis may occur due to systemic – pulmonary arterial anastomoses.

Diagnosis: Initial evaluation should include search for familial and treatable causes. Serum immunoglobulins (for hypogammaglobulinemia), sweat chlorides (for cystic fibrosis), Alpha 1 antitrypsin levels, neutrophil counts and serum complement levels may be useful. Assay of ciliary clearance or ciliary biopsy is useful for diagnosis of immotile cilia syndrome.

Anatomical localization may help in etiological diagnosis. Diffuse bronchiectasis is seen in patients with cystic fibrosis, immotile cilia syndrome, immunodeficiency states, chronic airway disease and allergic bronchopulmonary aspergillosis. In cystic fibrosis, the upper lobes are more involved than the lower lobes. Upper lobes may also be involved in aspiration, endobronchial tuberculosis and allergic bronchopulmonary aspergillosis. In all other forms the left lower lobe and lingula is more affected probably because the left bronchus is smaller in diameter and lacks gravitational drainage. Bronchiectasis on right side is predominant with foreign body or right middle lobe syndrome due to enlarged lymph nodes.

To establish the anatomic diagnosis, HRCT has replaced bronchography as the diagnosis of choice.

Bronchoscopy is indicated for the detection of persistent segmental atelectasis refractory to chest physiotherapy and lesions obstructing the airway. Its use is very limited.

Ventilatory and diffusion studies may reveal more widespread or severe pulmonary involvement than suspected otherwise.

Treatment

Bronchiectasis is often not progressive and patients may remain asymptomatic for extended periods. In these cases or at other extreme when the pulmonary disease is widespread and progressive, medical treatment is preferred. Chest physiotherapy and postural drainage are mainstays of treatment. Mucolytic agents such as aerolized recombinant human deoxyribonuclease may be useful in patients with cystic fibrosis. Prompt and rigorous antibiotic therapy is the cornerstone of the management.

If the symptoms cannot be controlled by antibiotic therapy and postural drainage and disease is progressive and localized, resection may be indicated.