Learn About Bronchiolitis
Bronchioles are small airways that connect your small breathing tubes (airways, or bronchi) to tiny air sacs of the lung. When these small airways are injured or inflamed, it is called bronchiolitis.
- Bronchiolitis occurs when the small airways in the lung become injured or inflamed.
- There are many causes of bronchiolitis, including inhaling strong irritants, infection, and some medications.
- Prognosis depends on the type and severity of injury.
What Is Bronchiolitis?
Bronchiolitis develops when small airways in the lungs become injured or inflamed. Inflammation can result directly from infections; medications; after bone marrow, stem cell, lung, and other transplants; and some types of arthritis. Injury can also result from exposure to any strong irritant, such as acids and toxic fumes.
How Bronchiolitis Affects Your Body
Regardless of the cause, the very small airways of the bronchioles become narrowed, and the easy passage of air is blocked. This may cause shortness of breath and cough. These symptoms may be very similar to other more common lung diseases, including asthma and chronic obstructive pulmonary disease (COPD).
How Serious Is Bronchiolitis?
Bronchiolitis is a relatively common lung condition in the United States, the most common cause being viral respiratory infections. Young children are the most commonly affected because they develop frequent respiratory infections that they may not be able to fight off as well as adults. How serious it is for any particular person depends on how severe the original injury was and how long this injury lasts. For cases related to infection, bronchiolitis often resolves without any permanent damage. If related to a toxic exposure, such as inhaling acid, some symptoms can remain present to some degree permanently. In some very specific situations, such as when bronchiolitis occurs after bone marrow or stem cell transplants, it may result in death or the need for lung transplant.
Often, bronchiolitis is severe enough to need treatment. Commonly used medications include anti-inflammatory corticosteroids.
Bronchiolitis Symptoms, Causes, and Risk Factors
What Are the Symptoms of Bronchiolitis?
Not everyone with bronchiolitis will have symptoms. When symptoms do occur, they are usually related to inflammation in the small airways. Shortness of breath and coughing are most common. When caused by an irritating substance, people may experience irritation in other parts of the body, including the eyes, nose, and throat. Bronchiolitis should be considered when these symptoms do not improve with treatment for common lung diseases, such as asthma or viral infection.
What Causes Bronchiolitis?
Bronchiolitis is the result of injury to the small airways in the lung. Different types of injury may cause different appearance of the small airways under the microscope after lung biopsy and a good way to think of bronchiolitis is that it is a general term to describe a pattern of lung damage that can occur for many different reasons. For example, bronchiolitis that occurs after inhaling a toxic substance is caused by direct damage to the small airways. Bronchiolitis that occurs with some forms of arthritis is caused by the immune system effect on the small airways.
What Are Risk Factors?
A person is at higher risk for developing bronchiolitis whenever they are exposed to a respiratory infection, inhaled irritant, or medical condition where injury to the small airways may occur. Common categories of risk factors for bronchiolitis include:
- Infections – including common cold viruses, influenza, measles and some forms of pneumonia. Young children are most at risk for developing bronchiolitis caused by infections.
- Inhaling toxic substances – including acid, chlorine, ammonia, or smoke.
- Medications – including gold, penicillamine, sulfasalazine, and rituximab.
- Arthritis – including rheumatoid arthritis and lupus.
- Organ transplantation
When to See Your Doctor
You should consult with your health-care provider if you experience coughing and breathlessness that does not go away or that occurs after a respiratory infection or inhaling a toxic substance.
Diagnosing and Treating Bronchiolitis
What to Expect
If your doctor thinks you may have bronchiolitis, he or she is likely to ask detailed questions about infections or exposures you may have had. You may expect detailed questions about where you live, where you may have traveled, and whether you have been exposed to certain chemicals or medications.
To diagnose bronchiolitis, it is usually important to rule out other medical problems, and this usually requires further testing. You can expect to undergo pulmonary function tests, a way to measure how well your lungs are working. These tests require you to do a number of breathing maneuvers, most often blowing into a tube or holding your breath for a short period of time. Another test often used in this situation is a CT scans. CT scans are a form of x-ray that produces very accurate pictures of your lungs, which can help doctors decide if bronchiolitis is present, and, if so, what type of bronchiolitis it may be.
If your medical history, along with the results of any pulmonary function tests and CT scans, does not offer a clear answer about whether you have bronchiolitis, your doctor may want to get a biopsy specimen of your lungs to figure it out.
How Bronchiolitis Is Diagnosed
Unless there is a clear history of infection, exposures, or other known causes of bronchiolitis, along with typical pulmonary function tests and/or CT scan, bronchiolitis may be a difficult diagnosis to make. It is usually only considered when people do not respond well to treatment for more common lung diseases like asthma or emphysema. Many patients ultimately require a procedure to obtain samples for a lung biopsy. Looking at small samples from the damaged lung through the microscope is the most accurate means for diagnosing the presence and type of bronchiolitis. That knowledge will help guide the doctor toward the best treatment.
How Bronchiolitis Is Treated
The most common treatments for bronchiolitis are usually prescription medications to help control specific symptoms. For instance, cough medications are used to suppress the cough, and inhalers are used to help with shortness of breath.
Other treatments for bronchiolitis usually depend on what is causing the injury to the airways. When bronchiolitis is caused by medication or inhaling a toxic substance, sometimes limiting exposure is enough. When bronchiolitis is the result of specific disease, such as arthritis, treatment might include medications against those diseases.
When symptoms are severe, steroids may be prescribed. Steroids are strong medications used to fight inflammation. They work by suppressing the immune system. While often effective, steroids may also have side effects, including increased appetite, increased blood sugar levels, and weight gain.
Questions to Ask Your Doctor About Bronchiolitis
Making notes before your visit, as well as taking along a trusted family member or friend, can help you through the first appointment with your doctor.
- How common is bronchiolitis?
- Will symptoms of bronchiolitis ever go away?
- What types of substances can cause bronchiolitis through sudden exposure?
- What are some side effects of medications used to treat bronchiolitis?
Living With Bronchiolitis
Most people with bronchiolitis lead productive lives without significant problems, as it may go away by itself, or with medication, or by avoiding harmful exposures.
Medications are prescribed to patients with symptoms or whose bronchiolitis is severe or is worsening. As many factors can cause bronchiolitis, it is not always possible to predict whether any single drug will work. Some drugs prescribed by doctors for bronchiolitis are listed here:
- Albuterol – this is an inhaled medication most commonly used for asthma. Albuterol dilates the bronchial tubes and can help with symptoms by causing the airways to open up slightly.
- Corticosteroids – prednisone is the most common corticosteroid used in the treatment of bronchiolitis and other lung conditions. Corticosteroids work by reducing inflammation through suppressing the immune system. Side effects include increased appetite, weight gain, high blood sugar levels. If taken for a long time, they can increase the risk of osteoporosis and cataracts.
- “Macrolide” antibiotics – azithromycin is the most commonly prescribed of these medicines. Although usually used to fight infection, these antibiotics also fight inflammation and are helpful in managing some lung diseases.
- Other medicines that affect the immune system – some drugs are rarely prescribed except for more severe cases. Their names include azathioprine, methotrexate and cyclophosphamide. They often require blood tests to make sure that the dosage is right.
Lung transplantation is very rarely recommended, and only for the sickest patients whose bronchiolitis is life-threatening, and who do not respond to medications.
Bronchiolitis is relatively common, so your doctor may be able to provide information or literature about it. The Lung Association recommends patients and caregivers join our Living with Lung Disease Support Community to connect with others facing this disease. You can also call the Lung Association’s Lung HelpLine at 1-800-LUNGUSA to talk to a trained respiratory professional who can help answer your questions and connect you with additional support.
Questions and Answers About Bronchiolitis
- Q: How common is bronchiolitis?
- A: Although bronchiolitis is common among young children, probably no one knows exactly how many adults have bronchiolitis. As it is most often caused by viral infections, it may get better by itself before it is ever diagnosed. Some of the uncertainty is because bronchiolitis is probably not a single disease itself. It may be easier to think of bronchiolitis as a type of lung injury that happens by a number of causes. Bronchiolitis, however, appears to be less common than asthma, emphysema, or bronchitis.
- Q: Will symptoms of bronchiolitis ever go away?
- A: This depends on what caused the bronchiolitis in the first place. If bronchiolitis began after an infection or inhaling something irritating, most people recover fully. Symptoms usually improve by staying away from that substance and/or taking medications, such as inhalers or steroids. With more severe forms of inhaled injury, there may be permanent abnormalities seen on breathing tests and x-rays, even when symptoms have entirely gone away. When bronchiolitis begins because of a noninfectious illness, such as arthritis, symptoms can be much harder to control, and symptoms may never go away entirely. For people with bronchiolitis obliterans, a severe form of bronchiolitis that often comes after organ or stem cell transplantation, bronchiolitis may require many medications and eventually lung transplant.
- Q: What types of substances can cause bronchiolitis through sudden exposure?
- A: Generally, these are industrial chemicals that dissolve easily in water. Among them are acids, bleaches, and ammonia. Many of these exist in strong cleaning fluids, kept in closets or under the sink. Some forms of these chemicals are found in machines we use every day, such as battery acids in cars.
- Q: What are some side effects of medications used to treat bronchiolitis?
- A: Albuterol, an inhaled bronchodilator commonly used for asthma, can cause the heart rate to speed up. Frequent users may experience a mild tremor in the hand. Corticosteroids work by suppressing the immune system. Therefore, people who take them may be more likely to get infections. Other side effects from steroids include increased appetite, weight gain, and higher sugar levels. The macrolide antibiotics most often used is azithromycin, commonly called “Z-pack.” Macrolides are usually well tolerated but can cause stomach upset. They can also cause subtle changes to the ECG or to hearing. Doctors who prescribe macrolides for long periods may check the ECG and recommend hearing tests about once a year.
Marc Feinstein, MD, FCCP
Date Last Reviewed