Bronchiectasis overview

# Overview
Bronchiectasis involves cycles of infections and inflammation that result in alveolar damage and inelastic dilated bronchi. Bronchiectasis may be classified based on either severity of localization of the disease. Bronchiectasis can be caused by both, congenital and acquired factors. Bronchiectasis must be differentiated from other diseases that cause dyspnea and cough, such as COPD, asthma, pneumonia, tuberculosis, chronic sinusitis, cough due to gastrointestinal reflux, upper airway cough syndrome, pulmonary carcinoma, and inhaled foreign body. Bronchiectasis is normally diagnosed after months or years of symptoms. The most common symptoms are a chronic cough and daily sputum production. The most common signs of bronchiectasis are coarse crackles, rhonchi, and wheezes on auscultation. There are both routine investigations and special case investigations. Routine investigations include sputum analysis, full blood count, and quantitative immunoglobulin levels. Cystic fibrosis and autoimmune testing are done if the patient is suspected of having an underlying condition. High-resolution computed tomography (HRCT) is the preferred diagnostic tool in identifying bronchiectasis. Along with treatment of bronchiectasis, it is important to treat the underlying condition if one is present. The medical therapy is divided into medical treatment and physiotherapy strategies. Surgical indications are life-threatening hemoptysis or disease that is unresponsive to medical treatment. Primary prevention of bronchiectasis is aimed at the prevention of future development with the avoidance of harmful substances, vaccinations, maintenance of a healthy body mass index (BMI), and the practice of physiologic strategies. To reduce the impact of the disease, patients should lead a healthy lifestyle, use prophylactic treatment when needed, do vaccinations, and practice physiotherapy strategies.

# Historical Perspective
In 1819, Rene Laennec, inventor of the stethoscope, was the first to describe bronchiectasis. In 1880s, Dr. William Osler, a Canadian physican, was the first to research bronchiectasis in detail.

# Pathophysiology
Bronchiectasis involves cycles of infections and inflammation that result in alveolar damage and inelastic dilated bronchi. Damage to the airway results in airflow obstruction and impaired clearance of secretions.

# Classification
Bronchiectasis may be classified based on either severity of localization of the disease. Based on severity, there are three pathological subtypes of bronchiectasis: Tubular/fusiform, varicose, and saccular. Based on localization, bronchiectasis may be either localized or generalized.

# Causes
Bronchiectasis can be caused by both, congenital and acquired factors. Congenital factors include conditions such as kartagener syndrome, cystic fibrosis, young's syndrome, yellow nail syndrome, alpha 1-antitrypsin deficiency, and primary immunodeficiencies. Acquired factors include post-infectious, AIDS, IBD, APBD, COPD, airway obstructions, alcohol, drugs, and irritants.

# Differential Diagnosis
Bronchiectasis must be differentiated from other diseases that cause dyspnea and cough, such as COPD, asthma, pneumonia, tuberculosis, chronic sinusitis, cough due to gastrointestinal reflux, upper airway cough syndrome, pulmonary carcinoma, and inhaled foreign body.

# Epidemiology and Demographics
Bronchiectasis affects extremes of age in certain indigenous populations with a slight female dominance. It is difficult to estimate the prevalence because it is often misdiagnosed. In developed countries, it is important to diagnose the underlying cause. The age of onset is adulthood. In developing countries, infection in childhood is a common cause.

# Risk Factors
There are some congenital and acquired conditions that cause inflammation and increased mucus secretion and accumulation of the airways. This repeated cycle leads to the increased risk of bronchiectasis.

# Screening
There is no routine screening for bronchiectasis. If the patient has an immune deficiency or primary ciliary dyskinesia then pulmonary function tests should be measures four times a year.

# Natural History, Complications, and Prognosis
Bronchiectasis is normally diagnosed after months or years of symptoms. Patients have respiratory complications, infection, and hemoptysis. Death can be caused by cardiac and respiratory failure. Bronchiectasis shows a higher mortality with males, advanced age, poor functional status, severe disease based on radiographic findings, and evidence of hypoxemia and hypercapnia.

# History and Symptoms
Symptoms of bronchiectasis can take months or even years to develop. The most common symptoms are a chronic cough and daily sputum production.

# Physical Symptoms
The most common signs of bronchiectasis are coarse crackles, rhonchi, and wheezes on auscultation.

# Diagnostic Studies

## Laboratory Findings
There are both routine investigations and special case investigations. Routine investigations include sputum analysis, full blood count, and quantitative immunoglobulin levels. Cystic fibrosis and autoimmune testing are done if the patient is suspected of having an underlying condition.

## Chest X-ray
Although the chest x-ray is not used for diagnosing bronchiectasis, it can be used for patients with respiratory symptoms who are suspected in having any of the differential diagnoses.

## CT
High-resolution computed tomography (HRCT) is the preferred diagnostic tool in identifying bronchiectasis. Common findings include increased diameter of a bronchus, tree-in-bud abnormalities, and cysts with definable borders.

## Other Imaging Findings
The bronchogram is no longer used for the diagnosis of bronchiectasis.

## Other Diagnostic Studies
Other diagnostic tools that can be used are pulmonary function tests, electron microscope examination, and bronchoscopy.

# Medical Therapy
Along with treatment of bronchiectasis, it is important to treat the underlying condition if one is present. The medical therapy is divided into medical treatment and physiotherapy strategies. The medical treatment consists of patient education and treatment of the acute exacerbations, prophylactic treatment, vaccination, and other therapies. The physiotherapy strategies focuses on airway clearance and pulmonary rehabilitation.

# Surgery
Surgical indications are life-threatening hemoptysis or disease that is unresponsive to medical treatment.

# Primary Prevention
Primary prevention of bronchiectasis is aimed at the prevention of future development with the avoidance of harmful substances, vaccinations, maintenance of a healthy body mass index (BMI), and the practice of physiologic strategies.

# Secondary Prevention
To reduce the impact of the disease, patients should lead a healthy lifestyle, use prophylactic treatment when needed, do vaccinations, and practice physiotherapy strategies.