CNN

The effects of long-term exposure to asbestos typically don't show up for at least 20 to 30 years after initial exposure, and sometimes longer. Signs and symptoms develop when damage and scarring caused by the asbestos fibers lead to stiffness in your lung tissue so that your lungs can't contract and expand normally (a form of pulmonary fibrosis). Once exposure to asbestos is stopped, however, the fibrosis stops progressing in the majority of cases.

Some asbestosis symptoms include:

• Shortness of breath, initially only with exertion, but eventually even while resting
• Decreased tolerance for physical activity
• Coughing
• Chest pain
• Finger deformity (clubbing) in some cases

Although most of these signs and symptoms are similar to those of other breathing disorders, such as asthma, the way in which they develop is different. In asbestosis the effects of the disease occur over months and years.

When to see a doctor
If you have a history of exposure to asbestos and you're experiencing increasing shortness of breath, talk to your doctor about the possibility of asbestosis. If it is asbestosis, your doctor may be able to prescribe treatment to relieve your symptoms. It's unlikely that the disease will progress after removal from exposure.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

When you inhale, air travels through your nose or mouth, down your throat, through your larynx to your trachea — the main passageway for air to your lungs. Your trachea splits into two branches called bronchi, one carrying air to the left lung, one to the right. Within each lung, the bronchi branch off over a dozen times into smaller and smaller airways. Some of the smallest of these airways (bronchioles) lead into tiny ducts (alveolar ducts) that end in microscopic air sacs (alveoli).

Alveoli have very thin, elastic walls that allow an exchange of gases vital to your health — oxygen flows from the alveoli into your bloodstream to nourish your body, and carbon dioxide flows from your bloodstream into the alveoli and on into your bronchi, to be expelled.

A natural screening system
Normally, microorganisms, dust and other foreign particles in the air you breathe are removed by microscopic hairs on the surface of your airways that beat hundreds of times a minute (cilia). The cilia sweep the particles into your upper airway, where the particles are swallowed into your digestive system, trapped in your nose hairs or expelled when you cough.

Even when unwanted particles do get into your lungs, immune cells destroy most of them. Alveoli, for example, house their own special cleanup crew — immune cells called macrophages, which are attracted to and ingest foreign substances, such as smoke particles, dust and chemicals.

Fibers resist breakdown
Unfortunately, asbestos fibers are difficult to destroy, even for macrophages. When a macrophage attempts to ingest an asbestos fiber, it often fails because the fiber is too long and partially resistant to breakdown. In the process, however, the macrophage leaks out substances that were supposed to destroy the foreign body, but these substances can also harm the alveoli. This causes the alveoli to become inflamed and eventually scar, a process referred to as fibrosis.

If many fibers are inhaled over a long period, the cumulative scarring of alveoli reduces their ability to exchange oxygen and carbon dioxide. The result is that your lung capacity diminishes, oxygen exchange is diminished, and you feel increasingly short of breath. Also, because the lungs are stiff, like a dried sponge, it takes a great deal of muscular effort to breathe.

For unknown reasons, not everyone exposed to asbestos for long periods develops asbestosis. Genetic factors may play a role.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Because asbestos occurs naturally in the environment, everyone breathes in some asbestos fibers. Usually, these are expelled before they reach the deeper areas of your lungs, but even if they do, a few fibers won't create signs and symptoms of asbestosis.

People most at risk of developing asbestosis are those who are exposed to high concentrations of asbestos for long periods of time, such as workers who were involved in the mining, milling, manufacturing, installation or removal of asbestos products. Most cases of asbestosis occur at least 10 years after the person's first exposure to asbestos.

Brief exposure to asbestos a few times in your life won't cause harm. However, it's always best to avoid direct exposure. Removal of asbestos products is generally considered a major project. If you decide to have it done, seek the help of a professional.

If you live, work or study in a building where existing asbestos has been contained and sealed, you're not at risk of asbestosis.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The severity of asbestosis is generally related to the amount and duration of exposure to asbestos. Effects of the disease may be so mild as to cause almost no symptoms. Or the condition may create such a reduced flow of oxygen as to be disabling or even fatal. Asbestosis may lead to the following conditions:

• High blood pressure in your lungs. Asbestosis-related scar tissue may eventually compress or obliterate your lungs' small blood vessels, causing high blood pressure in your lungs' arteries (pulmonary hypertension).
• Heart problems. Pulmonary hypertension can lead to enlargement and failure of your heart's right ventricle (cor pulmonale). Your heart consists of four chambers — two upper chambers called atria and two lower chambers called ventricles. Your right ventricle assists in pumping oxygen-poor blood from your organs and tissues to your lungs, where your blood receives a new boost of oxygen. As your pulmonary arteries narrow, your heart's right ventricle must work harder to pump blood through your lungs. Initially, your heart tries to compensate by thickening its walls and dilating the right ventricle to increase the amount of blood it can hold. But this measure only works temporarily, and eventually — after a period of a few years — the right ventricle weakens and fails from the extra strain.
• Lung cancer. If you smoke and have asbestosis, your chance of developing lung cancer increases greatly, especially if you smoke more than a pack of cigarettes a day. Tobacco smoke and asbestos both contribute to each other's cancer-causing (carcinogenic) effects, so that the combination of both risk factors together is more dangerous than the effects of either risk factor alone.
• Other lung damage. Exposure to asbestos can lead to other health complications, including changes in the thin membranes covering your lungs and lining your chest cavity (pleural membranes). Pleural changes may be the first signs of asbestos exposure and may include pleural thickening, the formation of calcium deposits in the pleura (plaques), and an abnormal accumulation of fluid between the membranes (pleural effusion). Pleural effusion itself is benign and doesn't increase your risk of asbestosis or malignant mesothelioma.
• Other cancer. People exposed to asbestos at an early age, for a long period of time or at high levels are at increased risk of malignant mesothelioma. Diagnosis and treatment of this cancer is often difficult. Malignant mesothelioma takes many years to develop. Most people with this condition were first exposed to asbestos at least 20 years — and sometimes as long as 50 years - prior to their diagnosis. While asbestos exposure is the primary risk factor for malignant mesothelioma, asbestosis itself doesn't increase your risk of this cancer, nor does malignant mesothelioma increase your risk of asbestosis.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

You're likely to start by first seeing your family doctor or a general practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to a lung disorders specialist called a pulmonologist or to an occupational medicine specialist.

If you work for a manufacturer where exposure to asbestos products is known, you may be required to have routine, yearly visits with a pulmonologist or occupational medicine specialist.

Because appointments can be brief and because there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready and on what to expect from your doctor.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance. This might include writing down a detailed history of your jobs since you first started working.
• Write down any symptoms you're experiencing. For asbestosis, it will help your doctor to have as many details as possible about when your symptoms first appeared and how they may have changed or worsened over time.
• Write down key personal information, especially related to possible environmental exposure to asbestos, even as long as 20 or more years ago. Take the time to think about jobs, remodeling projects, school environments or other experiences in your past when you may have been exposed to asbestos. For example, your doctor will want to know if you were in the military — especially the navy, where asbestos was formerly used extensively in shipbuilding.
• Make a list of your key medical information, including other conditions you're being treated for and the names of the medications that you're taking. Include on your list every prescription and over-the-counter drug you use, as well as any vitamins and supplements.
• Take film from any chest X-rays you've had in the last 20 years. It will help your doctor make a diagnosis if he or she can compare an old chest X-ray with the results of a current scan. The actual X-ray film is more important to your doctor than is the report.
• Take a family member or friend along, if possible. Sometimes it can be difficult to soak up all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.

Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out.

For asbestosis, some basic questions to ask your doctor include:

• What is likely causing my symptoms or condition?
• Do I have pulmonary asbestosis?
• Are there any other possible causes for my symptoms or condition?
• What kinds of tests do I need?
• Is my chest X-ray abnormal? Has it changed since the last one?
• Are there treatments that can help?
• What is my risk of long-term complications?
• How will you monitor my condition over time?
• Can I continue to work?
• Will it help if I stop smoking now?
• If the people I live with smoke, will it aggravate my condition?
• Do you know if I might qualify for workers' compensation, based on my symptoms?
• I have these other health conditions. How can I best manage them together?
• Are there any restrictions that I need to follow?
• Should I see a specialist? What will that cost, and will my insurance cover seeing a specialist?
• Are there any brochures or other printed material that I can take home with me? What Web sites do you recommend visiting?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.

What to expect from your doctor
Your doctor is likely to ask you a number of questions. Think about your answers ahead of time. Your doctor may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms stayed the same or gotten worse?
• What kind of work have you done in your career, starting from a young age through to the present?
• Have you been involved in any home-remodeling projects or other building renovations?
• Have any current or former colleagues been diagnosed with asbestos-related lung conditions?
• Have any close relatives, friends, or people with whom you've shared long-term projects or hobbies been diagnosed with a related condition?
• Do you or did you smoke? If so, how much?
• Have you been diagnosed or treated for any other medical conditions? When?

What you can do in the meantime
If you smoke or share a home with people who smoke, try to cut back on your exposure to smoke while you wait for your appointment. The symptoms of any heart or lung condition are made worse by inhaling smoke. No matter what your diagnosis, if you smoke, work with your doctor to make a plan for stopping.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

To help your doctor make an accurate diagnosis, provide him or her with a detailed history of your work activities and any other sources of possible exposure to toxic dusts. Tell your doctor about the availability of dust masks and other respiratory-protection devices in your workplace. Your doctor may also ask if you know of any fellow employees who have been diagnosed with a condition caused by exposure to asbestos.

Your doctor may detect a dry, crackling sound when listening to your lungs with a stethoscope. You may also undergo these diagnostic tests:

• Pulmonary function tests. These tests determine how well your lungs are functioning and may help in the diagnosis. Pulmonary function tests measure how much air your lungs can hold and the airflow in and out of your lungs. For example, you may be asked to blow as hard as you can into an air-measurement device called a spirometer. Some pulmonary function tests measure the amount of gas exchanged across the membrane between your alveoli and capillary blood vessels.
• Chest X-ray. A chest X-ray can often detect abnormalities in your lungs before you experience any symptoms. On an X-ray, areas of scar tissue that appear as small, scattered, opaque areas on the lining of your lungs are called pleural plaques. Although they indicate previous exposure to asbestos, they are not a predictor of asbestosis or malignant mesothelioma, a cancer that can occur in the tissue that surrounds the lungs. Asbestosis appears as excessive whiteness in your lung tissue. If the asbestosis is advanced, your entire lung may be affected, giving it a honeycomb appearance.
• Computerized tomography (CT) scan. In some cases, your doctor may request a computerized tomography (CT) scan of your lungs. These scans generally provide greater detail than does a usual chest X-ray. This may help detect asbestosis in its early stages, even before it shows up on the chest X-ray.

If you have ever had these tests in the past, try to get copies of those reports — and of actual X-ray films, if possible — to share with your doctor. These will provide critical information to help diagnose your condition.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

There's no treatment to reverse the effects of asbestos on the alveoli. Treatment focuses on preventing progression of the disease and relieving symptoms. The most important factor in keeping the condition from worsening is to eliminate exposure to asbestos. For most people, scarring of lung tissue doesn't begin or progress once exposure has ended.

The following may be components of asbestosis treatment:

• Smoking cessation. If you smoke, it's important to stop, particularly because of the extremely heightened risk of lung cancer. In addition, smoking may cause emphysema, which further reduces your lung reserves.
• Vaccinations. Because of your impaired lung condition, treat a cold or a bout of the flu promptly to avoid complications. Your doctor may advise you to receive flu and pneumonia vaccines.
• Medications. The complication of pulmonary hypertension is often treated with medications to expand or relax blood vessels, and blood-thinning medications to prevent blood clots from forming and obstructing narrowed vessels.

To ease difficulty breathing, your doctor may prescribe supplemental oxygen or drain fluid from around your lungs, if necessary. Occasionally, severe cases of asbestosis may be treated with lung transplantation.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Reducing the level of exposure to asbestos is the best prevention against asbestosis. In the United States, by law, a worker's exposure to asbestos may not exceed 0.1 fiber per cubic centimeter of air. Federal law requires employers in industries that work with asbestos products, such as construction and shipyard industries, to monitor exposure levels, create regulated areas for asbestos work, and provide their employees with appropriate training, protective gear such as face masks, and decontamination hygiene areas.

Many homes built before the 1970s contain asbestos products, such as building insulation, insulation for hot-water and steam pipes, soundproofing and decorative material sprayed on walls and ceilings, older stove-top and ironing board pads, as well as some types of textured paint, patch compounds, roofing and siding shingles, and vinyl floor tiles.

Generally, there's no cause for concern being around these products as long as they're in good condition and you don't disturb them or cause them to disintegrate. It's when they're damaged that there's a danger of asbestos fibers being released into the air. If you need repair or removal of an asbestos product, it's best to have it done by a professional.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.