All You Need to Know About Bronchiolitis Obliterans

All You Need to Know About Bronchiolitis Obliterans

The bronchiolitis obliterans is a chronic disease of the bronchioles. It is progressive and ultimately leads to the bronchioles becoming blocked. Sometimes a lung transplant needs to be performed in end-stage disease.

What is bronchiolitis obliterans?

Bronchiolitis obliterans is characterized by inflammatory processes in the bronchioles that do not recede. The bronchioles represent the small branches of the bronchial tree and already border on the alveoli of the lungs. They only have a single layer of ciliated epithelium and no more goblet cells. Their opening is only guaranteed by elastic fibers.

Furthermore, they further divide into four to five terminal bronchioles, which in turn divide into the approximately 1 to 1.35 millimeter long and 0.4 millimeter wide bronchioli respiratorii. Sometimes their wall is already formed by alveoli (pulmonary alveoli). The bronchioles thus open into the alveoli. Due to the chronic inflammatory processes in the bronchioles, the lung tissue is of course also constantly stressed.

As the inflammation progresses, scarring occurs, which leads to obstructions. The scars are created to contain the inflammation. However, the disease therefore progresses constantly and in the end stage forms a complete blockage of the bronchioles. Gas exchange is then no longer possible.


The causes of bronchiolitis obliterans are diverse. Previous infections, autoimmune diseases or the use of drugs can lead to chronic inflammation. Patients with rheumatic diseases can also develop chronic bronchiolitis. Bronchiolitis obliterans often develops as a result of chronic rejection after a lung transplant.

The Washington Morning Post also reported that workers who work in factories that make microwave popcorn often suffer from this disease. The diacetyl found in the butter aroma was blamed as the cause here. It is possible that allergic reactions to this compound initiate the inflammatory processes in the bronchioles.

In any case, the expression Popcorn Workers’s Lung has already been coined for this phenomenon. In the course of the inflammatory processes, a fibrin-rich exudate forms, which clogs the bronchioles and the outer alveoli. The bronchioles are closed in the long term by scarred remodeling processes with the formation of connective tissue and thus the gas exchange is hindered. The exact cause of these inflammatory processes is not known. However, it is believed that cytokines play a crucial role in the pathogenesis of the disease.

The exudate in the alveoli resulting from the inflammation causes the formation of granulation tissue in the bronchioles. However, with this temporary tissue, the openings of the bronchioles gradually become narrowed. In the advanced stage, the inflammation spreads to the neighboring lung parenchyma. This stage is known as bronchiolitis obliterans with organizing pneumonia (BOOP).

Symptoms, ailments & signs

Bronchiolitis obliterans is characterized by pathological background noises (stridor) during breathing. The noises occur especially when exhaling. In addition, the disease is characterized by increasing shortness of breath. The patient is also plagued by a constant and excruciating urge to cough. The breathing difficulties lead in the long term to an undersaturation of the blood with oxygen, which shows up as cyanosis in the form of bluish discolored lips.

The thorax is over-inflated. This is followed by states of exhaustion and often confusion as a result of a lack of oxygen supply to the brain. The symptoms are similar to those of bronchial asthma or COPD. The bronchial lumen is covered with tough mucus due to the constant formation of the fibrin-rich exudate. In the untreated final stage, life can only be saved by a lung transplant.

Diagnosis & course

In order to diagnose bronchiolitis obliterans, bronchial asthma and COPD must be excluded from the differential diagnosis. The symptoms of these diseases are the same. Imaging methods are not meaningful here, because here only changes are made visible that can have several causes. Only a lung biopsy can confirm the diagnosis.

Here the bronchiolitis becomes apparent, although there are no signs of inflammatory processes in the alveoli. This implies a clear indication of the chronic course of bronchiolitis, which only later spreads to the lung tissue. If bronchiolitis obliterans develops after a lung transplant, radiological examinations without a lung biopsy are often sufficient to confirm the diagnosis.


In the case of diseases of the bronchi, the function of the lungs can be impaired. Therefore, caution and compliance with medical diagnostics are required, as otherwise complications such as bronchiolitis obliterans will occur. This is especially true for young children, the elderly and patients who are infected by an infection after a lung transplant.

Once the disease has reached the level of the bronchioles, the patient will progressively deteriorate if the symptoms are ignored. The result is that healthy lung tissue is rejected or the transplantation is unsuccessful. The bronchiolitis obstructs the granulation tissue, the flow is obstructed and bulging scars form due to the restricted lung volume.

The scarring happens because the body tries to counteract previous inflammations that are still in the lungs. The healing process is counterproductive and is the most serious rejection reaction after a lung transplant. Antibiotics can no longer work and cortisone therapy lasting several months must be sought. Patients who are at increased risk of contracting inflammatory respiratory diseases need to be particularly careful of viral superinfections.

Small children, whose fine bronchial branches have been damaged, can be seriously endangered by diseases such as measles, influenza viruses or mycoplasma. Even if the symptoms of inflammation are mild, bronchiectasis, bronchopneumonia and complications such as obstructive ventilation disorder can occur in later adult life.

When should you go to the doctor?

Since bronchiolitis obliterans is a very serious disease, it is essential to consult a doctor. As a rule, the doctor should be contacted if there are various background noises and complaints during breathing. Difficulty breathing or gasping for breath can also indicate the disease and should be investigated.

Most patients suffer from persistent coughing and also from a blue discoloration of the skin and lips. A visit to the doctor is necessary even with these symptoms. Furthermore, bronchiolitis obliterans can lead to permanent tiredness or exhaustion. Patients are often confused or have difficulty concentrating. Therefore, if these symptoms occur for no particular reason, a doctor should be consulted to exclude or confirm the bronchiolitis obliterans.

As a rule, the ENT doctor or pulmonologist should be consulted with this disease. He can correctly assign and treat the complaints. However, in severe cases, a lung transplant, which is carried out in a hospital, is also necessary.

Treatment & Therapy

Once the diagnosis has been confirmed, action must be taken quickly to prevent the disease from progressing. Cortisone therapy lasting at least six months is suitable for this. If this treatment is not initiated, serious courses are to be feared. In some cases, cyclophosphamide or cyclosporine can also be used. A lung transplant is sometimes completed at the end of treatment for bronchiolitis obliterans.

In order not to let it get that far, the underlying disease should be looked for in order to treat it. Sometimes it may be enough to switch off the influence of certain environmental toxins. The phenomenon of the “Popcorn Workers’s Lung” has already been reported above. Here, the likely cause of the disease is the active ingredient diacetyl in the butter aroma.

Constant inhalation of toxic gases such as NO2 can also irritate the bronchioles. Preventing exposure to these toxins can in itself lead to an improvement in symptoms.

Outlook & forecast

Bronchiolitis obliterans usually has a poor prognosis. Among other things, it is itself a complication of lung transplantation, whereby the immune system is directed against the lung tissue that is foreign to the body. But also autoimmune reactions against the lungs or chronic inflammation as a result of infections or the influence of drugs irreversibly remodel the lung tissue in the long term. The course of the disease cannot be stopped, but drug treatment with immunosuppressants in the form of cortisone can slow down the remodeling processes.

The constant inflammation leads to the formation of fibrin and thus to scarring and narrowing of the bronchioles and the adjacent alveoli. This process is progressive and irreversible. There is an increasing number of respiratory problems that are getting worse all the time. There is currently no curative therapy.

The course of the disease becomes even more severe when the inflammation spreads to the neighboring lung parenchyma. Then bronchiolitis obliterans develops with organizing pneumonia, which is also known as BOOP. BOOP is characterized by a subacute onset with flu-like symptoms such as fever, fatigue, cough, increasing difficulty breathing and a feeling of severe illness.

In individual cases, this course can be very massive and life-threatening. But the long-term course of the disease also ultimately leads to death. 50 percent of patients die within three years. Only 30 to 50 percent of those affected live five years after diagnosis. Intensive drug therapy can, however, greatly delay the course of the disease.


A general recommendation for preventing bronchiolitis obliterans is to adhere to a healthy lifestyle with plenty of exercise, a balanced diet and refrain from smoking. However, since the causes of this disease are diverse, there is no guarantee that bronchiolitis obliterans will not break out despite a healthy lifestyle.


In most cases, the person affected with bronchiolitis obliterans has no special or direct follow-up measures available. The affected person is dependent on symptomatic treatment, since causal therapy is usually not possible in this disease. The earlier the disease is recognized, however, the better the further course is usually.

However, bronchiolitis obliterans usually leads to the death of the person affected and thus also to a significantly reduced life expectancy. In most cases, treatment of bronchiolitis obliterans is carried out with the help of drugs. The affected person should ensure that they are taken correctly and regularly.

The doctor’s instructions should also be observed, but in case of doubt or anything unclear, the doctor must always be contacted again. In order not to unnecessarily burden the body, one should also not smoke in bronchiolitis obliterans.

You should also refrain from strenuous physical work. In many cases, the disease also leads to physical upset or depression. These should always be treated by a psychologist, although discussions with your own family can also be very helpful.

You can do that yourself

Bronchiolitis obliterans is a very serious disease of the bronchi that often requires a lung transplant, even with professional treatment. Self-treatment of the disease is therefore completely out of the question. Those affected must definitely consult a doctor.

However, patients can also help to improve the disease themselves. Since bronchiolitis obliterans is associated with chronic inflammatory processes that permanently burden the body, those affected should ensure a healthy lifestyle that supports the immune system. A healthy diet, avoidance of excessive alcohol, adequate sleep and, if the patient is able to do so, light endurance sports in the fresh air are helpful. As with all diseases of the bronchi and lungs, smoking of tobacco should be avoided.

Simple home remedies can alleviate the strong and usually excruciating cough that is often associated with bronchiolitis obliterans. In natural medicine, sage- based preparations are used, which are available in the form of tea or lozenges. Gargling with salt water keeps the throat and throat area moist and has a disinfectant effect. This can prevent the area irritated by constant coughing from becoming inflamed.

If the cause of the disease could not be clarified, patients should consider whether there are allergenic substances in their (work) environment, for example chemicals, that could be the trigger for the disease and should make the attending physician aware of this.

Bronchiolitis Obliterans