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What is Popcorn Lung: Causes, Symptoms, Treatment, Diagnosis

What Is Popcorn Lung?

Popcorn Lung which is medically referred to as bronchiolitis obliterans is a rare disorder of the lung that affects the bronchioles. As the disease condition progresses, the inflammation as a result of Popcorn Lung cause significant scarring of the lung tissues and the airways become narrow making it difficult for the affected individual to breathe. The name Popcorn Lung was given to this condition since it was deemed to be caused by a chemical called diacetyl which was widely used in flavoring popcorns. In fact, the first case of Popcorn Lung was found in a person who used to work in a popcorn factory and was exposed to this chemical for prolonged periods of time [2].

Popcorn Lung can also be caused as a result of lung and bone marrow transplantation. Other cases of Popcorn Lung include side effects of certain medications, pulmonary infections, and some autoimmune conditions. An individual who develops Popcorn Lung without any history of any transplants tends to have symptoms that are quite similar to asthma or COPD. Due to the rarity of the condition, the diagnosis is often made by carrying out a biopsy of the lung which will clearly show scarring and inflammation. This is especially in people who have not had any transplants [1].

The severity of the condition can be found out by conducting a high resolution CT scan of the lungs. The treatment for Popcorn Lung is quite challenging and in non-transplant cases is treated by immunosuppression and steroid medications. However, in cases where a transplant is believed to be the cause of Popcorn Lung then physicians may opt for a re-transplantation even though the success rate of this procedure is quite variable [1].

What Is Popcorn Lung?

What Causes Popcorn Lung?

The primary cause of Popcorn Lung is prolonged exposure to a chemical called diacetyl. Some studies have hinted at certain genetic factors which also can cause Popcorn Lung but it is not considered to be a hereditary disease. The chemicals used in making candies, popcorn potato chips, and certain dairy products are the most prominent causes of Popcorn Lung. Additionally, fumes that emanate from factories containing ammonia and chlorine also increase the risk of an individual developing Popcorn Lung [2].

Individuals with continuous exposure to nitrous oxide gas also are at high risk for developing Popcorn Lung. Fumes that emanate from welding when inhaled also can lead to scarring of the lung tissues and narrowing of the airways such as that seen with Popcorn Lung. Aside from the external factors mentioned that increase the risk of an individual having Popcorn Lung, there are also certain other factors. These include viral or bacterial infections of the respiratory system. These infections often at times cause inflammation to an extent that there is narrowing of the airways and scarring of the lung tissues [2].

As stated, people who have had bone marrow or lung transplants often at times get Popcorn Lungs. There are also certain autoimmune disorders that increase the risk of Popcorn Lung of which rheumatoid arthritis is the most common. Another most common cause for Popcorn Lung is the use of e-cigarettes. These contain diacetyl which is responsible for scarring the lungs and causing Popcorn Lung. This has been confirmed by the American Lung Association which states that using the flavored varieties of e-cigarettes is the primary cause of Popcorn Lung [2].

Diacetyl is widely used in e-cigarette which is known to cause Popcorn Lung. However, many popcorn companies have stopped using this chemical but it is still widely used in e-cigarettes. A study conducted on e-cigarettes in 2015 which tested 50 popular brands of e-cigarettes found out that 40 out of the 50 brands contained diacetyl and put an individual at risk for developing Popcorn Lung. Additionally, the study also mentioned the use of another chemical called acetoin which also plays a key role in the development of Popcorn Lung [2].

However, since e-cigarettes came under the umbrella of the FDA in the United States only in 2016, the changes to the use of chemicals in e-cigarettes have still not occurred. However, as more research is done in this area this is expected to be done sooner rather than later to prevent cases of Popcorn Lungs [2].

What Are The Symptoms Of Popcorn Lung?

An individual with Popcorn Lung will have very mild symptoms and this is the reason why in many cases people tend to overlook them resulting in a delay in diagnosis. These symptoms are also quite familiar with other lung conditions, which also perhaps is one of the reasons why diagnosis of Popcorn Lung tends to get delayed. In fact, people with a known diagnosis of asthma may find it extremely difficult differentiate between the symptoms of Popcorn Lung and that of asthma [2].

The symptoms of Popcorn Lung can be observed after about two weeks after the infection or exposure to a chemical that causes Popcorn Lung. The symptoms then continue to worsen with time. In cases where transplantation is the cause of Popcorn Lung then the symptoms take over years to develop. The primary symptom of Popcorn Lung includes audible wheezing with no identifiable cause like asthma or bronchitis. The affected individual will also have problems with breathing and doing any activity will be a challenge for him or her [2].

People with Popcorn Lung tend to get exhausted with minimal physical activity for no apparent reason. The individual will also have persistent dry cough. The respiratory rate of people with Popcorn Lung also is significantly increased. Prompt medical attention is advised in cases where an individual gets short of breath with any activity or if they experience chest pain with difficulty breathing along with feeling dizzy. This becomes more apparent if these symptoms are persistent and continue to become worse over time [2].

How Is Popcorn Lung Diagnosed?

The diagnosis of Popcorn Lung is normally suspected if an individual has symptoms of lung disorders such as bronchitis or asthma with no apparent clinical diagnosis. Once Popcorn Lung is suspected, a detailed examination will be performed with radiographs of the chest and lungs in the form of x-ray, CT and MRI scan [2].

Additionally to confirm the diagnosis the following tests may also be done.

Bronchoscopy: This test is done to look for any abnormalities in the airways which may be causing the symptoms.

Biopsy: A lung biopsy may also be done for a detailed analysis and look for any other possible causes for the symptoms.

Pulmonary Function Tests: This test is essential to check the status of the lungs and whether there is any abnormality in the breathing pattern of the patient.

Depending on the results of these tests, a diagnosis of Popcorn Lung is made [2].

How is Popcorn Lung Treated?

With regard to the treatment of Popcorn Lung, in cases where the patient has not had any transplants that may be causing this condition, steroids are the primary mode of treatment to calm down the inflammation that occurs as a result of Popcorn Lung. The scarring of the lung tissues however is irreversible and the condition becomes incurable if it has progressed to the stage that there is significant constriction of the airways. Treatments in such cases are aimed at controlling the symptoms and prevent further damage to the lungs [2].

For treatment of Popcorn Lung, it is essential for the symptoms to be recognized at an early stage since delay in treatment can cause irreparable damage to the lungs and treatment will become that much more difficult. If Popcorn Lung is caused due to exposure to toxins and chemicals then staying away from that environment is the first thing that the patient needs to do. In cases where a bacterial cause is identified for Popcorn Lung, then macrolide antibiotics are given which have shown good efficacy in some patients [2].

For an autoimmune condition causing Popcorn Lung, treatment with medications that suppresses the immune system are prescribed to control the inflammation. For problems with breathing that are seen in people with Popcorn Lung, supplemental oxygen is also given to normalize it. In cases where the scarring has advanced beyond repair and the symptoms are severe then lung transplantation will be required to treat Popcorn Lung [2].

It is the severity of the disease and the rate at which the condition worsens is what that determines the overall prognosis of an individual with Popcorn Lung. The prognosis is the poorest in people who develop this condition as a result of autoimmune disorders like rheumatoid arthritis. Thus it is vital to get a diagnosis of Popcorn Lung early and get treated for it to prevent damage to the airways which may make the condition incurable [2].

Studies suggest that Popcorn Lung is a major contributing factor in the number of fatalities that occur after a bone marrow or a lung transplant. Studies estimate that about 50% of people who have had lung transplant and have survived for minimum of five years tend to develop the severest form of Popcorn Lung [2].

In conclusion, Popcorn Lung is a rare lung disorder in which the smallest airways of the lung get affected. There is also significant scarring of the lung tissues along with inflammation and narrowing of the airways which makes breathing extremely difficult for the patient. The primary cause for Popcorn Lung is inhalation of a chemical called diacetyl which is widely used as a flavoring agent in e-cigarettes. It was also used to flavor popcorns which is where this condition got its name but this is no longer the case [2].

It can also be caused due to bacterial and viral infections and autoimmune disorders. People who undergo bone marrow or lung transplants are also at an increased risk for developing Popcorn Lung. Steroids and immune suppressants are the primary modes of treatment; however, if the condition progresses where the scarring is severe and the airways get significantly constricted then this condition becomes incurable [2].

Popcorn Lung is a condition that can be prevented somewhat by adhering to certain lifestyle modifications. These include completely abstaining from use of flavored e-cigarettes or hookahs that contain flavoring agents like diacetyl. It is also important to avoid areas where there is a possibility of inhaling toxins which can cause scarring of the lungs, especially around chemical factories and plants [2].

People who have undergone transplants need to be extra careful and keep a close eye on the symptoms and get treated right away if they have any problems with breathing. In cases where exposure to chemicals and fumes cannot be avoided then wearing protective masks is a necessity and should be provided by the employer to prevent the fumes from damaging the lungs and causing conditions like Popcorn Lung [2].


Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:October 14, 2019

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