Definition and Overview

Emphysema is one kind of chronic obstructive pulmonary disease or COPD. Patients who develop emphysema experience difficulty in breathing. In emphysema, the inflammation caused by the disease results in destruction of the pulmonary tissues, especially those that are in close proximity to the small airways. An injury to these tissues results in the collapse of the airways. Air then gets trapped in the air sacs, and the lungs are unable to empty. The air sacs, also known as the alveoli, in the lungs thus become overinflated. These overinflated alveoli take up space in the thorax but do not contribute to gas exchange. This results in a form of airway obstruction, as the flow of air stops due to the overinflated alveoli.

In emphysema, the lungs lose its elastic property. The lung is stretched during inspiration, but due to air trapping, cannot return to its normal, relaxed state. Aside from this, emphysema also destroys the tiny blood vessels in the lungs, which are the passageways of the blood carrying the gases necessary for respiration. Thus, even the blood flow to the lungs is affected.

Approximately 24 million individuals have some form of COPD, and emphysema remains to be one of the most common causes of death in the world. It is usually caused by smoking.

Cause of Condition

Smoking remains to be the primary cause of emphysema. The toxic substances in cigarette smoke are believed to cause the irreversible damage to the linings of the airways, producing this disease. Cigarette smoking damages the tiny hairs in the airways, known as cilia. The cilia are responsible for clearing the airways of mucosal secretions that carry unwanted substances and bacteria in the lungs. Dysfunction of these tissues results in increased mucus production, decreased clearance, and ultimately, a higher risk of recurrent infection. At the same time, cigarette smoking also causes chronic inflammation and subsequent narrowing of the airways, further contributing to obstruction of the airflow. Smoking other substances, such as cigars, pipe and marijuana, and exposure to secondhand smoke, also puts the individual at risk. The risk of a smoker developing emphysema is approximately six times more than that of someone who doesn't smoke. Approximately 20% to 50% of smokers will develop COPD in their lifespan.

Alpha-1 antitrypsin deficiency is the next most common cause of emphysema. Alpha-1 antitrypsin deficiency is a genetic disorder wherein a patient has low levels of alpha-1 antitrypsin or AAT, in the blood. AAT serves to counteract the activity of trypsin, an enzyme produced by the body's white blood cells. AAT deficiency results in immune cells attacking and damaging the normal tissues in the lungs. In this subset of patients, emphysema typically develops at a much younger age. Approximately 3-5% of cases of emphysema are due to AAT deficiency.

Exposure to occupational hazards, specifically dust, chemicals and fumes from mining and welding, are responsible for approximately 20% of cases of emphysema. Exposure to air pollution, especially when combined with poor ventilation, is also believed to contribute to the development of this condition. People living in urban, industrialized areas have higher rates of COPD than those in rural communities, and this could be due, in part, to air pollution and secondhand smoke. A history of asthma and tuberculosis may also be associated with the development of emphysema. Genetics also seem to play a role, as it appears to occur more frequently in people who have relatives with COPD.

Key Symptoms

The hallmark symptoms of emphysema are cough, production of sputum and shortness of breath. The symptoms usually appear after years, even decades, of exposure, and are usually chronic.

A productive cough is usually the initial symptom of emphysema. By definition, the cough of emphysema is the type that is present for longer than three months in 1 year, for at least two years. This cough is typically associated with sputum production. Shortness of breath typically occurs later in the course of the disease but is usually the most bothersome symptom. Breathing is usually more difficult upon exertion, but in the more advanced stages, may be present even at rest. Many patients purse their lips in order to improve their breathing. Patients may present with episodes of wheezing, especially when experiencing acute exacerbations or infections. In these instances, patients may also be seen actively using the neck muscles and other accessory muscles to aid in breathing. Characteristically, patients develop barrel chests as the disease progresses, and frequently remain in a tripod position. In the end stages of the disease, patients may develop right-sided heart failure, which can present with enlargement of the neck veins and swelling of the lower extremities.

Who to See and Types of Treatments Available

Emphysema is best managed by a pulmonary specialist. If you experience a persistent cough that won't go away, and especially when it is associated with a sensation of breathlessness, you should consult a pulmonologist immediately. You will be requested to undergo some form of chest imaging, typically a chest x-ray or a computed tomography scan. If emphysema or COPD is highly suspected, spirometry or a pulmonary function test will be performed to confirm the diagnosis. Spirometry is used to determine and measure the obstruction in your airways.

Of all the aspects of the management of emphysema, smoking cessation is the most crucial. The risk of mortality is significantly decreased when the patient stops smoking. Lung function is improved and the progression of the disease is delayed. Oxygen support is also recommended, especially for patients with low levels of oxygen discovered upon close examinations. This has been shown to improve shortness of breath and decrease mortality, as well.

Bronchodilators are medications that can help improve emphysema symptoms. These medications are available in various forms, such as an inhaler or as nebules. Steroids may also be given to decrease inflammation in the lungs.

Surgery is used to treat the advanced stages of emphysema. In selected patients, lung volume reduction surgery, where part of the lung is removed to allow the other parts to expand, may offer benefits and improve the quality of life. Lung transplant may be performed for end-stage emphysema, but follows strict criteria for recipients.

References:

  • National Emphysema Foundation - www.emphysemafoundation.org/
  • American Lung Association
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