Bronchiolitis Obliterans: Causes, Symptoms & Treatment

Chest X-Ray
Chest X-Ray. Getty Images / Handout / Getty Images

Bronchiolitis obliterans is a serious, irreversible lung disease that causes inflammation and blockage of the smallest airways in the lungs: the bronchioles. It's also known as obliterative bronchiolitis, and its symptoms can closely resemble the symptoms of chronic obstructive pulmonary disease (COPD).

Bronchiolitis obliterans became better known in 2000 when Missouri health officials asked the federal Centers for Disease Control and Prevention (CDC) to help them investigate cases in former microwave popcorn plant workers from Jasper, Mo.

Ultimately, the health officials traced the outbreak to inhaled diacetyl, the chemical that gives microwave popcorn its buttery flavor.

From those cases, bronchiolitis obliterans earned the nickname "popcorn lung."

In 2015, CDC also identified workers from a coffee processing facility who suffer from bronchiolitis obliterans. There, the cause appears to be volatile organic compounds released by large quantities of coffee beans when they're ground.

Causes of Bronchiolitis Obliterans

In some people, it's not clear what causes bronchiolitis obliterans. However, several possible causes have been identified. These include:

The condition also develops in some people after a bone marrow, lung or heart and lung transplant. One study found that some 10% of people who received a bone marrow transplant from a donor developed bronchiolitis obliterans within five years of their transplant procedure, while other researchers note that 50% of lung transplant recipients develop the condition within five years.

Symptoms of Bronchiolitis Obliterans

While it can take years for symptoms of the disease to appear after a transplant, the following symptoms (which closely mimic those of COPD) may appear within two to eight weeks after exposure to toxic fumes or following a lung infection:

    Diagnosing the Condition

    To help diagnose the disease, doctors may order the following:

    A surgical lung biopsy, in which your surgeon removes a small piece of tissue from your lung to examine under a microscope, is the best way to diagnose bronchiolitis obliterans.

    When you have bronchiolitis obliterans, your lung function may decline slowly over time, so your doctor may ask you to repeat some medical tests, especially the lung function tests.

    Treatment: Medications, Lung Transplant

    Like COPD, bronchiolitis obliterans is irreversible. The following treatment, however, may help slow its progression:

    • rapid removal of exposure to the irritating toxin (if an inhaled toxin is the cause of the disease)
    • medication, including corticosteroids and drugs that reduce the body's immune response (immunosuppressants)
    • lung transplant

    Because bronchiolitis obliterans can be fatal if left untreated, early intervention is critical for successful management of the disease.

    Bronchiolitis obliterans is not the same condition as bronchiolitis obliterans organizing pneumonia, despite the similar names. Bronchiolitis obliterans organizing pneumonia is a rare form of non-infectious pneumonia that causes extensive inflammation in the lungs' bronchioles.


    Centers for Disease Control & Prevention and the National Institute for Occupational Safety and Health. Flavorings-Related Lung Disease fact sheet. Accessed Feb. 4, 2016.

    Ditschkowski M et al. Bronchiolitis obliterans after allogeneic hematopoietic SCT: further insight—new perspectives? Bone Marrow Transplantation. (2013) 48, 1224–1229.

    Verleden GM et al. Are we near to an effective drug treatment for bronchiolitis obliterans? Expert Opinion on Pharmacotherapy. 2014 Oct;15(15):2117-20.

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