Overview

What is popcorn lung

Popcorn lungs or bronchiolitis obliterans is a rare respiratory condition in which the bronchioles (the smallest branches of airway tubes in your lung) become inflamed and blocked. It can be caused by irritation from inhaling toxic substances or by infection, leading to scarring of tissues over time and difficulty in breathing and, in severe cases, can lead to respiratory failure. Popcorn lung can also occur after an organ transplant or stem cell transplant from a matched donor.¹

Why is bronchiolitis obliterans called popcorn lung

The condition was first discovered among workers at a microwave popcorn factory who inhaled diacetyl, a flavouring chemical used to give popcorn a buttery flavour. This flavouring chemical is also found in the liquid of electronic cigarettes and vapes. It is important to mention here that diacetyl is banned in the UK as an ingredient in e-cigarettes and vapes.²

Who has a higher risk of developing bronchiolitis obliterans?

People who come into direct and close contact with the toxic irritating substances that can cause bronchiolitis obliterans have a higher risk of developing the condition, especially those who are exposed to these substances over a long period of time. Also, some medical conditions and infections are associated with popcorn lung.³

Chemical substances associated with popcorn lung

• Acetaldehyde
• Ammonia
• Chlorine
• Diacetyl
• Formaldehyde
• Fumes from metal oxides
• Hydrochloric acid
• Mustard gas or sulfur mustard 
• Nitrogen oxides
• Sulfur dioxide

Medical conditions associated with popcorn lung

• Infections like some types of pneumonia and bronchitis
• Stevens-Johnson syndrome
• Organ transplant procedures
• Rheumatoid arthritis and some other rheumatoid conditions

Symptoms and signs of bronchiolitis obliterans   

• Shortness of breath (dyspnoea)
• Cough especially during and after exercise, and that has no other cause like cold or asthma
• Wheezing
• Chest pain
• Fatigue and exhaustion
• Fever
• Night sweats

Diagnosis of popcorn lung

Signs and symptoms of bronchiolitis obliterans are similar to many other respiratory and lung conditions, so to confirm the diagnosis your healthcare provider will do the following:⁴

• Take a full medical history and ask you about your smoking history
• Use a stethoscope to listen to your lungs and breathing for any abnormal sounds
• Do imaging tests like chest X-rays and CT scan
• Request a pulmonary function test (PFT) to see your lung function and capacity and how much air you can breathe in and out
• In some cases, a lung biopsy may be required, where a small piece of lung tissue is removed and sent to histopathological testing

Treatment of popcorn lung

Bronchiolitis obliterans is irreversible and there is no cure for it yet. However, some medications can manage and ease the symptoms, slow the progression of the disease, prevent deterioration, and improve your quality of life. It is important to stop or at least reduce your exposure to harmful chemical substances and to stop smoking and vaping. The earlier the disease was detected and diagnosed the better the prognosis. Medications provided can include the following:⁵

• Corticosteroids like prednisolone to decrease the inflammation
• Inhalers like albuterol dilate the bronchioles and help with breathing
• Supplemental oxygen

In some severe cases where medications don’t work, a lung transplant may be needed.

FAQs

What is bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is a condition of reduced lung function due to inflammation and fibrosis of the bronchioles. It is the most common type of rejection in lung transplant recipients.⁶

How can I reduce my risk of developing popcorn lung?

Avoid exposure to toxic chemicals and wear protective equipment if you work around them. Avoid using vapes, electronic cigarettes and second-hand smoke whenever possible.

Can you heal from popcorn lung?

No, popcorn lung is an irreversible chronic condition, you can’t heal the already existing damage to the lung but you can manage the symptoms and keep the condition from worsening. Bronchiolitis obliterans can be fatal if left untreated.

Summary

Popcorn lung, medically known as bronchiolitis obliterans, is a rare but serious condition characterised by inflammation and scarring of the bronchioles, the smallest airways in the lungs. This condition leads to airway obstruction and impaired lung function. It earned its nickname from cases observed in workers at microwave popcorn factories who were exposed to diacetyl, a chemical used for flavouring. However, other causes include exposure to other harmful chemicals, respiratory infections, or complications from organ transplants. Diagnosis of popcorn lung involves a combination of patient history, imaging tests such as high-resolution CT scans, and pulmonary function tests to assess breathing capacity. A definitive diagnosis may require a lung biopsy to identify the characteristic inflammation and scarring of the bronchioles. Treatment for popcorn lung focuses on managing symptoms and slowing disease progression, as there is no cure. Corticosteroids and immunosuppressive drugs are commonly used to reduce inflammation. Bronchodilators may help open the airways, and supplemental oxygen can assist with breathing difficulties. In severe cases, lung transplantation may be considered. Avoidance of further exposure to harmful chemicals is crucial for preventing the condition from worsening. Early detection and intervention are vital for improving the quality of life and prognosis in individuals with popcorn lung, underscoring the importance of occupational safety and prompt medical evaluation for those at risk.