Bronchiolitis obliterans


Informally known as popcorn lung, constrictive bronchiolitis.

A rare disease that results in obstruction of the smallest airways of the lungs, bronchioles, due to inflammation.

Bronchiolitis obliterans syndrome is marked by inflammation and scarring of the airways that leads to severe shortness of breath and dry cough.

Characterized by narrowing of the terminal airways and obliteration of the terminal bronchi.

Symptoms include a dry cough, shortness of breath, wheezing, and feeling tired.

These symptoms generally get worse over weeks to months.

It is not related to organizing pneumonia.

Pathology may show constrictive changes but also can show lymphocytic bronchiolitis, which may be associated with a better outcome.

Caused by toxic fumes, respiratory infections, connective tissue disorder, and following a bone marrow or heart-lung transplant.

Diagnostic methods include CT scan, pulmonary function tests, lung biopsy.

Differential diagnosis includes asthma.

Treatment includes : Corticosteroids, immunosuppressive medication, and lung transplant.

Prognosis is often poor.

Symptoms may not appear for 2-8 weeks following toxic exposure or infection.

Inflammation that results in scar tissue formation.

Diagnosis is by CT scan, pulmonary function tests, or lung biopsy.

Chest X-rays are often normal.

The disease is not reversible.

Treatment can slow deterioration.

It is characterized by fixed airway obstruction.

Inflammation and scarring in the airways of the lung, results in severe shortness of breath and dry cough.

Bronchiolitis obliterans reduces FEV1 to between 16% and 21%, of the 80% or greater expected to be normal

Symptoms can start gradually, or can occur suddenly.

Causes, include: collagen vascular disease, transplant rejection, viral infection, Stevens-Johnson syndrome, Pneumocystis pneumonia, drug reaction, aspiration and complications of prematurity, exposure to toxic fumes, rheumatoid arthritis, and aspiration of drugs.

The disorder may be idiopathic.

Industrial inhalants are known to cause various types of bronchiolitis, including bronchiolitis obliterans.

nylon-flock workers

workers who spray prints onto textiles with polyamide-amine dyes

battery workers who are exposed to thionyl chloride fumes

workers at plants that use or manufacture flavorings, e.g. diacetyl butter-like flavoring

exposure to trash burn pits.

Often misdiagnosed as asthma, chronic bronchitis, emphysema or pneumonia.

Tests to diagnose bronchiolitis obliterans include: chest X-rays, diffusing capacity of the lung tests (DLCO), spirometry, lung volume tests, high-resolution CT (HRCT), and lung biopsy.

Diffusing capacity of the lung (DLCO) tests are usually normal.

Spirometry tests usually show fixed airway obstructions and sometimes restriction.

Lung volume tests may show hyperinflation.

High resolution CT can also show air trapping, thickening in the airway and haziness in the lungs.

Transthoracic lung biopsies are preferable for diagnosis of constrictive BO compared to transbronchial biopsies.

This disease is irreversible.

Severe cases often require a lung transplant.

Bronchiolitis obliterans is a common complication of chronic rejection.

The combination of inhaled fluticasone propionate, oral montelukast, and oral azithromycin may be able to stabilize the disease and slow disease progression.

There are no known effective antibiotic treatments for prophylaxis of the condition.

There is a safety alert warning against long-term use of azithromycin to prevent bronchiolitis obliterans syndrome in patients with blood or lymph node cancers who have received donor stem cell transplants, as relapse rates of malignancy were increased.

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