What does emphysema look like?

Emphysema

Emphysema, also called pulmonary emphysema, condition characterized by widespread destruction of the gas-exchanging tissues of the lungs, resulting in abnormally large air spaces. Lungs affected by emphysema show loss of alveolar walls and destruction of alveolar capillaries. As a result, the surface available for the exchange of oxygen and carbon dioxide between inhaled air and blood traversing the lungs is reduced. In addition, loss of elastic tissue from the walls of the destroyed alveoli causes the lungs to expand within the chest cage. The expanded lungs compress the small bronchi and thus increase resistance to airflow. This is especially evident during expiration, when contraction of the muscles of the chest wall and abdomen increase intrathoracic pressure and further reduce the passage of air through the small bronchi.

emphysemaEmphysema destroys the walls of the alveoli of the lungs, resulting in a loss of surface area available for the exchange of oxygen and carbon dioxide during breathing. This produces symptoms of shortness of breath, coughing, and wheezing. In severe emphysema, difficulty in breathing leads to decreased oxygen intake, which causes headaches and symptoms of impaired mental ability.Encyclopædia Britannica, Inc.Read More on This Topic respiratory disease: Pulmonary emphysema This irreversible disease consists of destruction of alveolar walls. It occurs in two forms, centrilobular emphysema, in which the destruction…bronchitis: on lung tissueTissue damage, in the forms of bronchitis and emphysema, is evident when the cross section of a normal lung is compared with the lungs of light and heavy smokers.Encyclopædia Britannica, Inc.See all videos for this article

Tobacco smoking is the most common cause of pulmonary emphysema. In smokers, emphysema generally coexists with chronic obstructive bronchitis. In combination, these two conditions are known as chronic obstructive pulmonary disease (COPD).

Approximately 15 percent of regular cigarette smokers develop progressive pulmonary emphysema, generally beginning within the fourth or fifth decade of smoking. The reason that emphysema develops in some smokers but not in others is generally unknown. One factor that predisposes some individuals to emphysema is an inherited deficiency of alpha-1 antitrypsin, an enzyme that normally protects the lungs from injury caused by cigarette smoke. Smokers who inherit an abnormal gene for alpha-1 antitrypsin from both parents often develop progressive, severe emphysema, especially in the lower lungs, beginning before the age of 40. Nonsmokers who have the enzyme deficiency are generally unaffected.

Bullous emphysema is characterized by damaged alveoli that distend to form exceptionally large air spaces, especially within the uppermost portions of the lungs. This condition sometimes occurs in otherwise healthy young adults. Bullous emphysema often first comes to attention when an abnormal air space ruptures, leaking air into the pleural space and causing the affected lung to collapse (see pneumothorax). The victim experiences sudden onset of sharp chest pain and shortness of breath. Impaired breathing requires insertion of a tube through the chest wall in order to allow air to escape from the chest cavity. In severe cases, surgery may be necessary to repair the areas of the lung that have ruptured.

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Original Editors – Students from Glasgow Caledonian University’s Cardiorespiratory Therapeutics Project.

Top Contributors – Valentina Mazzoni, Esraa Mohamed Abdullzaher, Kim Jackson, Evan Thomas and Michelle Lee

Definition/Description

Emphysema can be defined as having a loss of lung elasticity, permanent enlargement of the air spaces distal to the terminal bronchioles, and destruction of the alveolar walls. It can be classified under the umbrella term chronic obstructive pulmonary disorder (COPD) .
There are three types of emphysema; centriacinar, panacinar, paraseptal. Centriacinar emphysema affects the alveoli and airways in the central acinus, destroying the alveoli in the walls of the respiratory bronchioles and alveolar ducts . Panacinar emphysema affects the whole acinus . Paraseptal emphysema is believed to be the basic lesion of pulmonary bullous disease .

Epidemiology

Emphysema is generally found in those less than 40 years old, and more frequently found in those of Scandinavian descent, commonly developing in the 3rd to 5th decades of a life . The disease tends to express no signs and symptoms until 50% of lung function is lost, as a result of the airway obstructions beginning in the smaller airways . 1% of cases of emphysema are thought to be due to the deficiency of the alpha1-antitrypsin enzyme .

The statistics relating to Emphysema are usually held within the wider spectrum of COPD, causing death to more than 14 million Americans, it is thought to be the fourth leading cause of deaths in America . Within England and Wales, 1.5 million people are said to be affected by Emphysema being within the top 5 leading causes of death

Aetiology

The exact cause of Emphysema is still yet to be distinguished, however research is suggesting the prevalence is strongly related to smoking, air pollutions and in some cases, occupation . Another common association is the deficiency of the enzyme alpha₁-antitrypsin, which is the protein protecting the alveoli .

The prevalence of Emphysema within the smoking population is believed to increase as smoking is a major risk factor associated. It is thought to have a higher incidence in those with a lower socioeconomic background, therefore affecting lifestyle and environment, resulting in the likelihood of respiratory infection .

Pathophysiology

The alveoli and the small distal airways are primarily affected by the disease, followed by effects in the larger airways . Elastic recoil is usually responsible for splinting the bronchioles open. However, with emphysema, the bronchioles lose their stabilizing function and therefore causing a collapse in the airways resulting in gas to be trapped distally.

There is an erosion in the alveolar septa causing there to be an enlargement of the available air space in the alveoli . There is sometimes a formation of bullae with their thin walls of diminished lung tissue.

Smoking contributes to the development of the condition initially by activating the inflammatory process . The inhaled irritants cause inflammatory cells to be released from polymorphonuclear leukocytes and alveolar macrophages to move into the lungs . Inflammatory cells are known as proteolytic enzymes, which the lungs are usually protected against due to the action of antiproteases such as the alpha1-antitrypsin . However, the irritants from smoking will have an effect on the alpha1-antitrypsin, reducing its activity. Therefore emphysema develops in this situation when the production and activity of antiprotease are not sufficient to counter the harmful effects of excess protease production . A result of this is the destruction of the alveolar walls and the breakdown of elastic tissue and collagen. The loss of alveolar tissue leads to a reduction in the surface area for gas exchange, which increases the rate of blood flow through the pulmonary capillary system .

Investigations

CT scan is a common method used to diagnosis emphysema. The observations mainly seen to identify emphysema are a decrease in lung attenuation and a decrease in the number and diameter of pulmonary vessels in the affected area .

Clinical Manifestations

Patients diagnosed with emphysema may complain of difficult/laboured breathing and reduced exercise capacity as their predominating symptoms . The loss of the elastic recoil in the lungs leads to irreversible bronchial obstruction and lung hyperinflation, which increases the volume over normal tidal breathing and functional residual capacity .

Outcome Measures

The main aims of treating patients with Emphysema are to relieve symptoms and to improve quality of life . To measure patients’ quality of life, the St George’s Respiratory Questionnaire (SGRQ) and the Guyatt’s Chronic Respiratory Questionnaire (CRQ) are often completed in order to measure the effectiveness of a treatment intervention .

Diagnostic Procedures

Generally, the diagnosis for Emphysema can be based on clinical, functional and radiographic findings . However, it is thought that mild Emphysema is not well detected on conventional chest radiography, therefore the use of pulmonary function tests (PFT) are often used to try and diagnose the condition .

In order to accurately diagnose Emphysema, the history of the patient’s condition needs to be fully understood . The use of high-resolution CT scans is part of the standard procedure when trying to detect this condition as it is non-invasive and is found to be sensitive in detecting pathological changes related to Emphysema .

Physiotherapy and Other Management

Physiotherapy management for Emphysema is commonly associated with similar management of COPD. The use of a pulmonary rehabilitation programme consisting of exercise and education can be designed by the physiotherapist along with other members of the multi-disciplinary team (MDT) in order to maximise the patients exercise capacity, mobility and also self-confidence . The other MDT members can consist of a respiratory nurse and dietitians, as well as the physiotherapist in the hope to treat each patient like an individual and meet their specific needs by tailoring a programme to suit them .

Prevention

As COPD is the umbrella term used for diseases like Emphysema, the prevention strategies are very similar. The most common suggestion for preventing emphysema, and such, is to stop smoking, and to avoid breathing in any harmful pollutants .

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Learn about Emphysema

Emphysema is one type of chronic obstructive pulmonary disease (COPD). It means destruction of the lung. In emphysema, the breathing tubes are narrowed and the air sacs are damaged. These changes lead to shortness of breath with daily activities. The major cause of emphysema is smoking cigarettes.

Key Facts

  • The breathing tubes are narrowed and air sacs are destroyed in emphysema.
  • Cigarette smoking is the major cause of emphysema
  • Shortness of breath with activities is the most common complaint.

To understand emphysema, it is important to consider briefly, “What is COPD?” COPD is a common lung condition that includes two conditions – emphysema and chronic bronchitis. In emphysema, the damage occurs to the breathing tubes and to the air sacs.

  1. Breathing tubes – attachments that hold the breathing tubes open are destroyed and result in collapse of the breathing tubes when breathing out.
  2. Air sacs – the walls of the air sacs are destroyed causing enlargement

In contrast, with chronic bronchitis the glands that line the breathing tubes produce too much mucus which blocks the passage of air when breathing out. Those diagnosed with chronic bronchitis cough up mucus most days. It is common to have both chronic bronchitis and emphysema.

About 1 out of 5 people who smoke at least a pack or more of cigarettes each day for at least 10 years “gets” COPD. It would be great if doctors could take a blood sample and identify those at risk for developing emphysema. There is one recognized inherited risk factor for emphysema called alpha-1 antitrypsin deficiency. A blood test can show whether someone has a low level of this protein.

How emphysema affects your body?

Collapse of the breathing tubes when breathing out can prevent emptying all of the air out of the lungs. This trapped air pushes down the main breathing muscle called the diaphragm and makes it less effective. This process is called hyperinflation – too much air in the lungs – and makes it harder to breathe.

The damage to the air sacs makes it harder for oxygen to pass into the blood vessels of the lungs. As a result, the oxygen level in the body is frequently reduced. The body tries to compensate for the low oxygen by breathing more. This process also makes those with emphysema feel like breathing is difficult.

Many of those diagnosed with emphysema gradually lose weight and are thin.

How serious is emphysema?

Changes to the lungs with emphysema are permanent, and the damage can vary from mild to very severe. In mild cases, shortness of breath may only occur with exercise. In more advanced cases, the individual may have breathing difficulty walking from one room to another and may require the use of oxygen.

Unfortunately, there is no treatment to reverse or repair the damage once it has occurred. However, stopping smoking and avoiding breathing in “bad air” can prevent the damage from getting worse.

Emphysema Symptoms, Causes and Risk Factors

The damage to the lungs with emphysema usually occurs as a slow pace. It is common that the individual may not realize that emphysema has developed until breathing difficulty interferes or limits the ability to perform daily activities.

What are the symptoms of emphysema?

Shortness of breath with physical activities is the major symptom. In those with advanced emphysema, breathing difficulty may occur when seated or when lying down. A cough that is either dry or produces mucus, wheezing, and chest pain are not usual symptoms of emphysema.

What causes emphysema?

The main cause of emphysema is cigarette smoking. Inhaling “bad air” such as second-hand smoke, dust, and fumes can also damage the lungs. Another cause of emphysema in some countries is inhaling smoke from indoor fires used for heating and cooking. There is one inherited cause of emphysema called alpha-1 antitrypsin deficiency. The alpha-1 protein protects the lung from damage. With a deficient or low level of the protein, the effects of smoking or inhaling “bad air” damage the lungs more readily. This process may occur at an early age, such as someone in their 40s or 50s.

What are the risk factors?

The major risk factor is smoking cigarettes. Having a parent or grandparent with emphysema also increases the risk if you smoke. Inhaling irritants in the air such as smoke and fumes may also contribute to emphysema. A low level of a protein in the blood – alpha-1 antitrypsin – is a hereditary risk factor for emphysema.

When to see your doctor

You should see your healthcare provider if you experience shortness of breath with daily activities. You should not assume that this is because you are “getting old” or are “out of shape.” If you are currently a smoker, or you used to smoke cigarettes, and find that it is hard to breathe with activities, make sure to tell your healthcare provider.

Diagnosing and Treating Emphysema

Emphysema can be diagnosed in two different ways. The most common approach is a breathing test. Another approach is a CT scan of the chest. However, a CT scan is not done routinely to diagnose emphysema.

What to expect

You can expect that your healthcare provider will ask you a lot of questions about whether you have breathing difficulty, cough up mucus, or experience chest pain and wheezing. If you have shortness of breath, the healthcare provider will want to know what activities cause you to feel this way, and whether you have breathing difficulty when you sleep. You can expect questions about past and current smoking cigarettes and inhaling irritants in the air at work or at home.

Your healthcare provider will want to know if you have any family members who have a lung problem such as emphysema/COPD.

You can expect your healthcare provider to exam you and listen to your chest with a stethoscope when you breathe in and out and also listen to your heart beating.

Most likely, your healthcare provider will order breathing tests either in the office or at the local hospital. Breathing tests provide information about how your lungs are working.

Diagnosis and Treatment

How It’s Diagnosed

Breathing tests are used to diagnose emphysema. After you take a deep breath in, you will be told to exhale, or blow out, fast and hard into a machine. Because of collapse or narrowing of the breathing tubes in emphysema, there is slowing of air when breathing out. This is called airflow obstruction.

You may also be asked to do another breathing test which measures whether there has been damage to the air sacs. This test is called diffusing capacity. After you blow all of the air out from your lungs, you will be told to take a deep breath in and hold it for 10 seconds. A reduced value suggests damage to the air sacs.

Based on your medical history, physical examination findings, and the results of the breathing tests, your healthcare provider will decide whether you have emphysema.

Your healthcare provider may also diagnose emphysema if you have a CT scan of the chest for some reason, like to evaluate a “spot” or nodule in the lung that was seen on a chest x-ray. The CT scan can show the damage to the lungs that has occurred in emphysema. However, CT scans of the chest are not routinely done to diagnose emphysema.

How It’s Treated

There is no treatment to repair damage to the lungs in emphysema. The most important thing that you can do is not smoke and not breathe in “bad air.” By doing these, you can prevent the emphysema from getting worse. If you are a current smoker, you need to quit today.

Treatment is intended to improve shortness of breath and to reduce the risk of an exacerbation (worsening of breathing symptoms usually due to a chest infection). Inhaled bronchodilator medications are the cornerstone of treating emphysema. These medications open the breathing tubes to make it easier to get all of the air out and thus make it is easier to breathe. There are two different types of inhaled bronchodilators which work in different ways to open the breathing tubes. They are frequently used together for greatest effect.

Regular use of long-acting inhalers (once or twice a day) is generally recommended because they last longer than short-acting inhalers (used every 4 – 6 hours and as needed). Oxygen may be prescribed if your saturation value is 88% or less. This is measured by putting a device on your finger called an oximeter. Starting a pulmonary rehabilitation program is the one of the best ways to improve shortness of breath, quality of life, and ability to exercise. In some cases, surgical treatments may be considered depending on your situation. An operation may remove parts of your lung that are very damaged or destroyed and that interfere with more normal parts of your lung.

Living with Emphysema

Even though you or a loved one may have emphysema, it is important to focus on what you, or your loved one, can do and not on what is difficult or hard to do. Make sure that you know as much as possible about your condition in order to function at the highest possible level. You should know the names of the medicines that you are taking for emphysema and how long they are supposed to work. Also, you should have an action plan in case your breathing gets worse.

What to Expect

You can expect that emphysema will get worse if you continue to smoke and continue to inhale second hand smoke and other irritants in the air. Stopping smoking will slow down the emphysema from getting worse. Many individuals find that they reduce activities to avoid breathing difficulty. Over time, this can make shortness of breath worse because less activity leads to being “out of shape” and possible weight gain.

You can expect that using inhaled medications will open the airways and make it easier to breathe. And you can also expect to be able to be more active if you exercise regularly either on your own or by participating in a pulmonary rehabilitation program. For many individuals who follow recommended treatments, your breathing may remain stable for a long time.

Managing the Disease

Ideally, you should lead a healthy life style that includes not smoking, eating healthy foods, having normal body weight, exercising regularly, getting 7 – 8 hours of sleep each night, and avoiding too much stress. A yearly flu shot is recommended to reduce the chances of getting the flu. There are two different pneumonia shots which are recommended to prevent to the most common bacterial cause of pneumonia. It is important to use your inhaled medications correctly and as prescribed by your healthcare provider on a regular schedule.

You should have an albuterol inhaler to use if you experience an increase in difficulty with your breathing. This medicine opens the breathing tubes quickly, but only lasts 3 – 4 hours.

You should make sure that you get a written action plan from your healthcare provider and have it available in case your breathing gets worse. Most action plans recommend using your rescue inhaler every 2 – 4 hours as needed and calling your healthcare provider if you have a chest cold or start to cough up yellow or green mucus. You should call your healthcare provider if you experience any major change in your breathing, Regular appointments with your healthcare provider are important to monitor your emphysema and to consider any new treatments..

Finding Support

Various types of information are available about COPD and emphysema. Some local hospitals and clinics offer monthly support groups for COPD. The internet includes numerous websites for those with COPD and their families that include basic information about emphysema/COPD, updates on what is new, and the opportunity to submit questions to a health- care expert. Here are some places to get more information about COPD and emphysema.

Organization Website

American Lung Association
COPD Foundation
Healthline
National Heart, Lung, and Blood Institute
WebMD
Montreal Chest Institute of McGill University
Donald A. Mahler, MD

Questions to Ask your Doctor About Emphysema

  • Is my COPD more emphysema or chronic bronchitis?
  • Did I inherit emphysema from my parents?
  • What treatments are available to help me breathe easier?
  • Will oxygen help me?
  • Does the local hospital have a Better Breather support group?
  • Does the local hospital have a pulmonary rehabilitation program?

Author

Donald A. Mahler, MD, FCCP

Date Last Reviewed

January 2018

Emphysema

Emphysema is a type of COPD (chronic obstructive pulmonary disease). COPD is a group of lung diseases that make it hard to breathe and get worse over time. The other main type of COPD is chronic bronchitis. Most people with COPD have both emphysema and chronic bronchitis, but how severe each type is can be different from person to person.

Emphysema affects the air sacs in your lungs. Normally, these sacs are elastic or stretchy. When you breathe in, each air sac fills up with air, like a small balloon. When you breathe out, the air sacs deflate, and the air goes out.

In emphysema, the walls between many of the air sacs in the lungs are damaged. This causes the air sacs to lose their shape and become floppy. The damage also can destroy the walls of the air sacs, leading to fewer and larger air sacs instead of many tiny ones. This makes it harder for your lungs to move oxygen in and carbon dioxide out of your body.

The cause of emphysema is usually long-term exposure to irritants that damage your lungs and the airways. In the United States, cigarette smoke is the main cause. Pipe, cigar, and other types of tobacco smoke can also cause emphysema, especially if you inhale them.

Exposure to other inhaled irritants can contribute to emphysema. These include secondhand smoke, air pollution, and chemical fumes or dusts from the environment or workplace.

Rarely, a genetic condition called alpha-1 antitrypsin deficiency can play a role in causing COPD.

Who is at risk for emphysema?

The risk factors for emphysema include

  • Smoking. This the main risk factor. Up to 75 percent of people who have emphysema smoke or used to smoke.
  • Long-term exposure to other lung irritants, such as secondhand smoke, air pollution, and chemical fumes and dusts from the environment or workplace.
  • Age. Most people who have emphysema are at least 40 years old when their symptoms begin.
  • Genetics. This includes alpha-1 antitrypsin deficiency, which is a genetic condition. AAlso, smokers who get emphysema are more likely to get it if they have a family history of emphysema.

At first, you may have no symptoms or only mild symptoms. As the disease gets worse, your symptoms usually become more severe. They can include

  • Frequent coughing or wheezing
  • A cough that produces a lot mucus
  • Shortness of breath, especially with physical activity
  • A whistling or squeaky sound when you breathe
  • Tightness in your chest

Some people with emphysema get frequent respiratory infections such as colds and the flu. In severe cases, emphysema can cause weight loss, weakness in your lower muscles, and swelling in your ankles, feet, or legs.

How is emphysema diagnosed?

To make a diagnosis, your health care provider

  • Will ask about your medical history and family history
  • Will ask about your symptoms
  • May do lab tests, such as lung function tests, a chest x-ray or CT scan, and blood tests

What are the treatments for emphysema?

There is no cure for emphysema. However, treatments can help with symptoms, slow the progress of the disease, and improve your ability to stay active. There are also treatments to prevent or treat complications of the disease. Treatments include

  • Lifestyle changes, such as
    • Quitting smoking if you are a smoker. This is the most important step you can take to treat emphysema.
    • Avoiding secondhand smoke and places where you might breathe in other lung irritants
    • Ask your health care provider for an eating plan that will meet your nutritional needs. Also ask about how much physical activity you can do. Physical activity can strengthen the muscles that help you breathe and improve your overall wellness.
  • Medicines, such as
    • Bronchodilators, which relax the muscles around your airways. This helps open your airways and makes breathing easier. Most bronchodilators are taken through an inhaler. In more severe cases, the inhaler may also contain steroids to reduce inflammation.
    • Vaccines for the flu and pneumococcal pneumonia, since people with emphysema are at higher risk for serious problems from these diseases
    • Antibiotics if you get a bacterial or viral lung infection
  • Oxygen therapy, if you have severe emphysema and low levels of oxygen in your blood. Oxygen therapy can help you breathe better. You may need extra oxygen all the time or only at certain times.
  • Pulmonary rehabilitation, which is a program that helps improve the well-being of people who have chronic breathing problems. It may include
    • An exercise program
    • Disease management training
    • Nutritional counseling
    • Psychological counseling
  • Surgery, usually as a last resort for people who have severe symptoms that have not gotten better with medicines. There are surgeries to
    • Remove damaged lung tissue
    • Remove large air spaces (bullae) that can form when air sacs are destroyed. The bullae can interfere with breathing.
    • Do a lung transplant. This is might be an option if you have very severe emphysema.

If you have emphysema, it’s important to know when and where to get help for your symptoms. You should get emergency care if you have severe symptoms, such as trouble catching your breath or talking. Call your health care provider if your symptoms are getting worse or if you have signs of an infection, such as a fever.

Can emphysema be prevented?

Since smoking causes most cases of emphysema, the best way to prevent it is to not smoke. It’s also important to try to avoid lung irritants such as secondhand smoke, air pollution, chemical fumes, and dusts.

NIH: National Heart, Lung, and Blood Institute

What is the difference between emphysema and COPD?

The main difference between emphysema and COPD is that emphysema is a progressive lung disease caused by over-inflation of the alveoli (air sacs in the lungs), and COPD (Chronic Obstructive Pulmonary Disease) is an umbrella term used to describe a group of lung conditions (emphysema is one of them) which are characterized by increasing breathlessness. A person with emphysema has COPD; however, not everybody with COPD has emphysema.

What is emphysema?

Emphysema is one of the lung conditions included in the term COPD. Normal lung tissue resembles a sponge; however, the lungs of people with emphysema look like an old used sponge, with large holes in them and a limited ability to “spring-back” into shape.

Emphysema is a progressive disease, that usually starts slowly with small holes between the alveoli, which eventually collapse to form larger air spaces. Old air gets trapped in these air spaces, which makes it difficult for people to inhale fresh air. Blood flow through the alveoli is also impaired meaning that people with emphysema not only struggle to breathe but have trouble receiving enough oxygen.

Cigarette smoking is by far the biggest cause of emphysema, but also the most preventable. Emphysema is more common with age and in males, and it tends to run in families. Other causes include air pollution, airway reactivity, and a deficiency of alpha-1-antitrypsin.

Treatment is with bronchodilator inhalers, which help to open up the airways, corticosteroids to relieve inflammation, and oxygen therapy. Antibiotics are usually also needed regularly as people with emphysema are prone to infections.

What is COPD?

COPD is an umbrella term for three lung conditions that damage the lungs, impair airflow, and make breathing progressively more difficult over time. The three conditions are emphysema, chronic bronchitis, and refractory (non-reversible) asthma. COPD is the third leading cause of death in the U.S. and rates appear to be increasing.

Emphysema is explained above. In chronic bronchitis, the lining of the airways is irritated and inflamed and thickens with mucus. Coughing is frequent and breathing becomes difficult.

In refractory asthma, a severe form of asthma, the airways swell, become narrow and produce extra mucus. Symptoms such as wheezing, coughing, shortness of breath and chest tightness are present most of the time and asthma attacks that do not respond to treatment are frequent. Aggressive treatment, including corticosteroids, is required.

Symptoms of COPD typically include breathlessness, difficulty breathing, increased phlegm, and chest tightness. COPD cannot be cured; however, treatments can improve symptoms and prevent further damage.

The GOLD Emphysema Staging System

This is a set of guidelines established by the Global Initiative for Chronic Obstructive Lung Disease (GOLD).

It measures how much air you can blow out of your lungs in 1 second. Doctors call this the forced expiratory volume (FEV1).

If you have emphysema, your doctor will look at your FEV1. He’ll also look at your other symptoms, as well as how many times you’ve been hospitalized in the past year because of them. Doctors call this an “exacerbation.” It means your symptoms flare up or suddenly get worse.

Your doctor may also do a CT scan of your lungs. He’ll then use all of this information to place you into one of the following four groups (they tell you how severe your emphysema is):

Group A (GOLD 1 or 2): Your symptoms are very mild. Your FEV1 is 80% or more. You might have had no flare-ups over the past year, or perhaps just one. You weren’t hospitalized for your symptoms.

Group B (GOLD 1 or 2): Your FEV1 is between 50% and 80%. You have more symptoms than people in Group A. This is the stage where most people see their doctor for coughing, wheezing, and shortness of breath.

You might have had one major flare-up, but you haven’t been in the hospital for your symptoms within the past year.

Group C (GOLD 3 or 4): Air flow into and out of your lungs is severely limited. Your FEV1 is between 30% and 50%.

You’ve had more than two flare-ups in the past year, or you’ve been admitted to the hospital at least once.

Group D (GOLD 3 or 4): It’s extremely hard for you to breathe in or out. You’ve had at least two flare-ups in the past year, or you’ve been hospitalized at least once.

Doctors call this “end-stage” COPD. That means you have very little lung function. Any new flare-ups could be life-threatening.

Pulmonary Emphysema: Diagnosis and Treatment

The etiology, pathology, diagnosis, and treatment of emphysema—a component of COPD—are discussed.

By William V. Wojciechowski, RRT

Pulmonary emphysema is defined, in pathological terms, as the permanent enlargement of air spaces distal to the terminal bronchioles and the destruction of the alveolar walls (without fibrosis). It is a chronic obstructive pulmonary disease (COPD), along with chronic bronchitis. Asthma is excluded from the COPD classification. When the obstructive pattern associated with asthma is reversed, either spontaneously or via medical intervention, the patient is essentially asymptomatic.

Epidemiology and Etiology

As a component of COPD, pulmonary emphysema causes health problems worldwide. Among more than 14 million patients with COPD in the United States, 1.65 million have emphysema and 12.5 million are affected by chronic bronchitis.1 The American Lung Association2 ranks emphysema 15th among chronic conditions contributing to activity limitations, and 44% of patients with emphysema claim to have limitations in their daily living activities resulting from their disease. More than 17,800 deaths are attributable to emphysema in the United States each year.2 The economic impact of emphysema in particular, and of COPD in general, will significantly contribute to the stress imposed on the health care system as average life expectancy increases.

The prevailing cause of pulmonary emphysema is cigarette smoking. Air pollution has been implicated as a cause, but no conclusive data support this notion. Air quality, however, affects individuals who already have emphysema to the extent that air pollution can provoke an exacerbation.

The relationship between cigarette smoking and the incidence of COPD is unusual in that almost 90% of patients with COPD have smoked, but only about 20% of smokers develop COPD.3 Emphysema usually occurs in people 50 or more years old, following decades of smoking. Nonetheless, emphysema develops before 50 years of age in those born with a1–protease-inhibitor deficiency.

Pathogenesis

The pathogenesis of emphysema is grounded in the protease and protease-inhibitor theory. The roots of this theory extend to 1897, when Camus and Gley4 recognized that serum had the capacity to inhibit the proteolytic enzyme trypsin. In 1905, Opie5 discovered that white blood cells contained proteolytic enzymes. Soon after, the suggestion was made that the serum’s inhibitory capacity conferred protection on tissues against proteolytic enzyme destruction. The specific protein that inhibited trypsin was identified later and was called a1-antitrypsin because of its inhibitory activity.6 This protein has been discovered to protect against other proteolytic enzymes and is now often referred to as a1-protease inhibitor (a1-PI).

The normal serum a1-PI concentration is 20 to 50 mol/L or 150 to 350 mg/dL. Serum levels of a1-PI of less than 11 mol/L or 80 mg/dL are considered deficient. Leukocytes, specifically neutrophils (polymorphonuclear leukocytes), contain various proteolytic enzymes in their lysosomes. Alveolar macrophages, derived from monocytes, also contain proteolytic enzymes. The role of these polymorphonuclear leukocytes and alveolar macrophages is to protect the terminal gas-exchange structures of the lungs from inhaled debris and infectious agents. In the process of defending the lungs from these invaders, these phagocytic cells release large quantities of proteolytic enzymes (elastase, cathepsin G, and proteinase) and an array of oxygen radicals (superoxide anions, hydrogen peroxide, hydroxyl radicals, and hypochlorous acid). These proteolytic enzymes and oxygen radicals are microbicidal. The abundance of these microbicidal agents causes the destruction of the cell membrane of the invading microorganism and, ultimately, its demise.

The presence of such toxic products in proximity to the lungs should cause irreversible tissue damage and destruction; however, the lungs normally remain unscathed. The presence of a1-PI and antioxidants in the serum, in cell membranes, and in the alveolar lining fluid layer restrains these toxic products, at the cellular level, from pursuing a potentially lethal course.

The antioxidants located in the lungs are widely distributed and consist of both enzymes and nonenzymes. The major enzymatic antioxidants include superoxide dismutase, glutathione, and catalase. The primary nonenzymatic antioxidants are membrane-bound vitamin C (ascorbic acid) and vitamin E (tocopherol).

Cigarette smoke is a rich source of oxidants. One oxidant, the semiquinone radical, reduces oxygen to superoxide anions. This biochemical event can lead to a cascade of other biochemical reactions. For example, a superoxide anion can react with hydrogen peroxide in the presence of the ferrous ion to produce the hydroxyl radical. The oxidants in cigarette smoke become involved in innumerable biochemical reactions, producing overwhelming numbers of free radicals.

The a1-PI molecule is susceptible to oxidative injury during smoking, rendering a1-PI ineffective in neutralizing proteolytic enzymes. Large numbers of neutrophils are summoned to the site in response to biochemical stimuli to join alveolar macrophages in cleaning up debris from cigarette smoke. In the process, elastase and other proteolytic enzymes are unleashed in the lungs, where these phagocytic cells act virtually unchecked and damage lung tissue. The damage takes the form of degradation of proteoglycans, glycoproteins, elastin, and other extracellular matrix constituents. Elastase also can stimulate inflammation by increasing interleukin-8 synthesis, impair healing by inactivating cytokines and growth factors, and produce pulmonary surfactant abnormalities. These and other injurious events triggered by cigarette smoke damage the lung’s connective-tissue elements and destroy lung parenchyma, thereby producing increased pulmonary compliance, early airway closure during expiration, and air trapping.

Research data challenge the protease and protease-inhibitor theory’s ability to describe the sole or primary pathogenesis for emphysema. Mounting evidence points to collagenase as inflicting damage on fibrillar collagen, which constitutes 50% to 60% of the lung’s extracellular matrix.7 As the major component of the pulmonary extracellular matrix, collagen provides tensile strength in lung tissue and helps to maintain alveolar interdependence.

D’Armiento et al8 demonstrated, in mice, the development of emphysema linked to collagen loss in the absence of a breakdown in elastin. A study9 on the role of collagenase released by alveolar macrophages has revealed the presence of more alveolar macrophages in bronchoalveolar lavage fluid obtained from the lungs of emphysema patients than in fluid from healthy subjects. Increased collagenolytic activity was also found within the lungs of emphysema patients. Recent evidence reveals that the degradation of elastin is not solely responsible for the development of emphysema from cigarette smoking. Collagen breakdown in the lungs appears to play a contributory role.

Alpha-1 Proteinase Inhibitor Deficiency

Alpha-1 proteinase inhibitor deficiency (a1-PI) is a liver-derived glycoprotein consisting of a polypeptide chain of 394 amino acids. Its concentration in the plasma increases as much as fivefold in response to tissue injury and inflammation, affording tissue protection.

a1-PI deficiency is a genetic disorder causing a decreased serum concentration of a1-PI. This autosomal-codominant disorder affects about one in 2,000 live births among people of European descent. Although a number of a1-PI variants exists, most do not cause the serum concentration of a1-PI to drop below 80 mg/dL. The three most common of the 75 known alleles are the M, S, and Z. The M variant is the healthy form that directs the body to produce a normal a1-PI molecule. The S variant is seldom associated with a1-PI deficiency emphysema; however, the Z mutation, characterized by one amino-acid substitution (lysine for glutamine), causes the serum concentration of a1-PI to plummet because this substitution impedes the release of a1-PI from the liver into circulation. Consequently, a person having the Z variant has a higher risk of developing genetic emphysema.

Genetic emphysema accounts for approximately 2% of all emphysema in the United States.10 One current theory regarding a1-PI deficiency is that the low serum level of a1-PI cannot neutralize the proteases released by the alveolar macrophages and neutrophils when these phagocytic cells become active in response to inflammation and pulmonary infections. Therefore, the proteolytic enzymes, over decades, damage lung tissue. The onset of emphysema from a1-PI deficiency often occurs at an earlier age than that caused by cigarette smoking, being seen in patients 30 to 50 years old. Cigarette smoking frequently accelerates the onset of emphysema associated with a1-PI deficiency. Asthma is a common misdiagnosis because the patient generally complains of chronic shortness of breath, chronic cough, wheezing, and pulmonary infections. Making the correct diagnosis of a1-PI deficiency typically takes several visits to multiple physicians over approximately seven years.11

Pathology

The two basic forms of emphysema are centriacinar (centrilobular) and panacinar (panlobular). An acinus, or lobule, is composed of respiratory bronchioles, alveolar ducts, and alveolar sacs. Centriacinar emphysema involves only the respiratory bronchioles. The alveoli here undergo permanent enlargement and damage to their walls. The alveolar ducts and alveolar sacs distal to the respiratory bronchioles on the same acinus usually do not experience this damage. Centriacinar emphysema is more common than the panacinar form. It predominates in the upper lobes, and is the variety seen among cigarette smokers; however, because the tissue damage during the later stages of centriacinar emphysema often extends to the alveolar ducts and sacs, distinguishing centriacinar from panacinar emphysema at that point becomes impossible.

Panacinar emphysema affects the entire acinus; therefore, the alveoli on the respiratory bronchioles, alveolar ducts, and alveolar sacs become permanently enlarged and experience alveolar-wall destruction. The architecture of the whole acinus is destroyed and replaced by thin-walled air spaces of variable sizes and shapes. These dilated air spaces result from inflammatory destruction of the acinus. This form of emphysema develops frequently in the lower lobes and is the characteristic variety seen in patients with a1-PI deficiency.

Regardless of the form of emphysema present, the structures affected sustain the same architectural rearrangements. Consequently, identical abnormalities prevail in both centriacinar and panacinar emphysema. The damage done to the alveolar walls results in a loss of the lung’s elastic recoil. As a result, effort is needed to perform exhalation. Pursed-lip breathing is generally employed during exhalation to empty the lungs as much as possible.

Enlarged alveoli cause oxygen molecules to travel increased distances to contact alveolar walls to diffuse out of the alveoli and into pulmonary capillaries, many of which have been destroyed. This increases the diffusion time of oxygen across the alveolar-capillary membrane.

Diagnosis

Emphysema often exists in conjunction with chronic bronchitis in the COPD population; nonetheless, emphysema and chronic bronchitis are two distinct diseases. Although a diagnosis of emphysema can, technically speaking, be made only upon postmortem examination, enough evidence can be accumulated from medical history, physical assessment, and diagnostic procedures to make the correct clinical diagnosis.

A patient with emphysema typically seeks medical intervention when shortness of breath occurs while performing ordinary daily activities, such as ascending a flight of stairs. Coughing is usually absent; if it exists, the cough tends to be minor and devoid of sputum. The clinician must obtain thorough social and medical histories because the information gained may reveal that the patient is a cigarette smoker and/or has a relative with a1-PI deficiency.

Characteristic findings can be seen upon physical examination. The patient generally displays tachypnea, lengthened expiratory time, use of accessory muscles of ventilation during inspiration and exhalation, pursed-lip breathing, increased heart rate, and increased anteroposterior chest-wall diameter (barrel chest).

The patient’s posture also may be revealing. Emphysema patients frequently attempt to increase the vertical dimension of the thorax to achieve a mechanical advantage for the muscles of ventilation. For example, when sitting, they place both elbows on the arms of the chair and lean forward. Palpation tends to demonstrate decreased vocal and tactile fremitus because the hyperaerated condition of the lungs creates a suboptimal environment for the transmission of sound waves. Similarly, hyperresonant notes are perceived via percussion, and auscultation reveals diminished or distant breath sounds.

A chest radiograph generally cannot establish the diagnosis of mild emphysema. No remarkable findings appear when mild emphysema exists; however, when emphysema is fully established, classic radiographic findings on an anteroposterior view are typically observed. These findings include bilaterally hyperlucent lungs, flattened hemidiaphragms with widened costophrenic angles, and horizontal ribs. The peripheral vascular markings frequently abate quickly. On the other hand, the markings become prominent when the patient has pulmonary hypertension and cor pulmonale. A lateral view shows an increased retrosternal airspace.

Typically, the heart appears long and narrow because it is influenced by the downward pull created by the flattened hemidiaphragms. In the presence of cor pulmonale, the right ventricle appears enlarged because of right-ventricular hypertrophy.

Spirometry documents the presence of chronic airflow obstruction. Forced vital capacity (FVC) measurement provides data for assessment of expiratory airflow. Measurements of FVC, forced expiratory volume in 1 second (FEV1/FVC), show the presence and degree of airflow obstruction.

A prebronchodilator-postbronchodilator study may indicate some degree of improvement in the quality of the forced expiratory airflow. The FEV1 itself is a useful index of physiological impairment because it correlates closely with the extent of a person’s functional disability and prognosis. An FEV1 of less than 1 L indicates a dismal prognosis.

Carbon monoxide diffusing capacity (dlco) testing is performed in conjunction with spirometry to assist in differentiating emphysema from asthma and chronic bronchitis. In emphysema, the dlco is usually decreased because of the loss of surface area of the alveolar-capillary membrane. The combination of a decreased FVC, a decreased FEV1, a decreased dlco, and increased lung volumes and capacities is generally diagnostic of emphysema.

Arterial blood-gas data tend to vary according to the stage of emphysema. In the mild and moderate stages, the PaO2 and the PaCO2 measurements may remain normal or, while the PaO2 stays normal, the PaCO2 can be decreased (respiratory alkalosis). In the moderately severe and severe forms of emphysema, the patient is likely to be hypoxemic and hypercarbic (respiratory acidosis).

High-resolution CT may be useful in the diagnosis of subclinical or mild emphysema. High-resolution CT scanners furnish images of low-attenuation lesions associated with emphysema.

Treatment

The major goal in treating emphysema is improving the patient’s quality of life. Smoking cessation is a primary focus. Avoidance of exposure to other noxious gases (including secondhand smoke and air contaminants in general) is stressed to lessen the deterioration of lung function.

Many medications are available for emphysema patients. The pharmacological mainstays are bronchodilators and anti-inflammatory agents. The bronchodilators primarily used are b2-agonists and anticholinergics. Two b2-agonists frequently prescribed are albuterol and salmeterol. Ipratropium bromide is an anticholinergic bronchodilator that sometimes affords emphysema patients improved expiratory airflow. A combination of albuterol and ipratropium bromide is also available in a metered-dose inhaler. Not all emphysema patients derive clinical benefit from bronchodilators; however, some clinicians believe that emphysema patients, especially those who have an FEV1 of less than 2 L, should be given a 1-week trial of a bronchodilator.

According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD),12 prolonged treatment with inhaled glucocorticosteroids does not alter long-term deterioration in FEV1 in patients with COPD. Some clinicians prescribe a 2-week trial of an oral glucocorticosteroid to identify patients who respond favorably to these anti-inflammatory agents. These patients are then prescribed an inhaled glucocorticosteroid to minimize the adverse reactions to this drug seen with long-term oral administration. GOLD advocates a trial of 6 weeks to 3 months to identify patients who may experience symptomatic relief and, possibly, benefit from prolonged treatment.

Theophylline has been used; however, its effectiveness in treating emphysema has been questioned because theophylline inhibits multiple phosphodiesterase enzymes. Phosphodiesterase-4 is the primary enzyme in the metabolism of cyclic adenosine monophosphate in smooth muscle. The selective phosphodiesterase-4 inhibitor cilomast, which is a bronchodilator that also reduces inflammation, demonstrates promise in the treatment of emphysema and COPD in general.

Oxygen therapy constitutes the cornerstone of treatment in emphysema. Prolonged use of oxygen for 15 hours per day increases the life expectancies of patients experiencing chronic respiratory failure.13 For patients who have a PaO2 of 55 mm Hg or less (or a pulse-oximetry result of 88% or less), supplemental oxygen is indicated. The administration of oxygen to these patients generally improves gas exchange, decreases the work of the heart, reduces pulmonary vascular resistance, and improves the ability to perform activities of daily living. Oxygen is usually administered via standard nasal cannula or some type of oxygen-conserving device.

Lung-volume–reduction surgery (LVRS) is another method for treating emphysema. In the advanced stages of emphysema, the lungs overfill the thoracic cavity because of the loss of lung elasticity. This condition contributes to airway compression, difficulty in breathing, and the use of accessory ventilatory muscles. LVRS involves reducing the size of the lung by excising a lung section. The smaller lung is better accommodated inside the thorax, and this enables the ventilatory muscles to work more efficiently; however, no randomized controlled studies support the therapeutic benefit of LVRS, compared with nonsurgical intervention.

Single-lung transplantation is performed more commonly among COPD patients than in any other patient population. Its success rate among COPD patients, compared with patients having other diseases, is favorable; however, emphysema patients experience the worst survival rate among patients with chronic airflow limitation. Data14 have shown that patients with the lowest dlco results experience the poorest outcomes.

Replacement or augmentation therapy restores a1-PI serum levels to normal in patients with a1-PI deficiency. Purified human a1-PI is delivered intravenously at a dose of 60 mg/kg every 2 weeks at a yearly cost of approximately $30,000. Attempts are being made to aerosolize a1-PI. Randomized clinical studies investigating the efficacy of intravenous replacement therapy have yet to be conducted.

Gene therapy is being explored. Researchers have used valine to replace methionine at the site where a1-PI is susceptible to oxidative damage. This amino-acid substitution prevents oxidative damage to the a1-PI molecule.

The treatment armamentarium for emphysema is being improved; however, emphysema is a devastating disease that can often be prevented by avoiding cigarette smoking. All healthcare workers should promote smoking prevention and cessation.

RT

William V. Wojciechowski, RRT, is associate professor and chair, baccalaureate degree respiratory therapy program, Department of Cardiorespiratory Care, University of South Alabama, Mobile.

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