Bronchiolitis obliterans
Encyclopedia
Bronchiolitis obliterans (BO), also called obliterative bronchiolitis (OB) and constrictive bronchiolitis (CB), is a rare and life-threatening form of non-reversible obstructive lung
disease in which the bronchiole
s (small airway branches) are compressed and narrowed by fibrosis
(scar tissue) and/or inflammation
. Bronchiolitis obliterans is also sometimes used to refer to a particularly severe form of pediatric bronchiolitis caused by adenovirus.
Bronchiolitis means inflammation
of the bronchioles and obliterans refers to the fact that the inflammation or fibrosis of the bronchioles partially or completely obliterates the airways.
and scarring occur in the airways of the lung, resulting in severe shortness of breath and dry cough.
FEV1 (forced expiratory volume in 1 second) should be above 80% of predicted values to be considered normal. Bronchiolitis obliterans reduces this to 16% to 21%.
Symptoms include:
The symptoms can start gradually, or severe symptoms can occur suddenly.
in organ transplant
patients, viral infection (respiratory syncytial virus, adenovirus, HIV
, cytomegalovirus
), Stevens-Johnson Syndrome
, Pneumocystis pneumonia
, drug reaction, aspiration and complications of prematurity (bronchopulmonary dysplasia
), and exposure to toxic fumes, including: diacetyl
, sulfur dioxide
, nitrogen dioxide
, ammonia
, chlorine
, thionyl chloride
, methyl isocyanate
, hydrogen fluoride
, hydrogen bromide
, hydrogen chloride
, hydrogen sulfide
, phosgene
, polyamide-amine dyes, mustard gas and ozone
. It can also be present in patients with rheumatoid arthritis. Certain orally administrated emergency medications, such as activated charcoal
, have been known to cause it when aspirated. Additionally, the disorder may be idiopathic
(without known cause).
Industrial workers who have presented with bronchiolitis:
In rare instances, bronchiolitis obliterans may be caused by inhalation of airborne diacetyl
, a chemical used to produce the butter-like flavoring in many foods such as candy, microwave popcorn and wines. This first came to public attention when eight former employees of the Gilster-Mary Lee popcorn plant in Jasper, Missouri
, developed bronchiolitis obliterans. In 2000, the Missouri Department of Health called in NIOSH to make a determination of the cause, and to recommend safety measures. After surveying the plant and each patient's medical history, NIOSH recommended respiratory protection for all workers in microwave popcorn production. Due to this event, bronchiolitis obliterans began to be referred to in the popular media as "Popcorn Lung" or "Popcorn Workers Lung".
One heavy consumer of microwaved popcorn has been diagnosed with this disease, which is the first known case involving a consumer.
On 27 August 2007, Weaver Popcorn Company of Indianapolis
promised to replace the diacetyl butter flavor ingredient in Pop Weaver popcorn with another flavoring.
In September 2007, Dr. Cecile Rose, pulmonary specialist at Denver's National Jewish Medical and Research Center, warned federal agencies that consumers, not just flavoring or food factory workers, may be in danger of contracting bronchiolitis obliterans. David Michaels, of the George Washington University
School of Public Health, first published Rose's warning letter on his blog.
On 4 September 2007, the Flavor and Extract Manufacturers recommended reduction of diacetyl in butter-like flavorings. The next day ConAgra Foods
announced that it would soon remove diacetyl from its popcorn products.
On 16 January 2008, it was announced that Wayne Watson, the Denver consumer who developed "popcorn lung" after inhaling microwaved popcorn, was suing the Kroger
grocery store chain and its affiliates. In the lawsuit, filed in U.S. District Court, Watson's attorney claimed that the companies "failed to warn that preparing microwave popcorn in a microwave oven as intended and smelling the buttery aroma could expose the consumer to an inhalation hazard and a risk of lung injury."
Diacetyl is approved by the Food and Drug Administration as a safe flavor ingredient, but there is evidence to suggest that inhalation in large amounts is dangerous. There are currently no warnings from federal regulators about diacetyl.
, bronchitis
, emphysema
, or pneumonia
.
Diagnosis may include the following tests:
results or unusual decreases in repeated measurements.
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
disease in which the bronchiole
Bronchiole
The bronchioles or bronchioli are the first airway branches that no longer contain cartilage or glands in their submucosa. They are branches of the bronchi.The bronchioles terminate by entering the circular sacs called alveoli.- Structure :...
s (small airway branches) are compressed and narrowed by fibrosis
Fibrosis
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This is as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue...
(scar tissue) and/or inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
. Bronchiolitis obliterans is also sometimes used to refer to a particularly severe form of pediatric bronchiolitis caused by adenovirus.
Bronchiolitis means inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
of the bronchioles and obliterans refers to the fact that the inflammation or fibrosis of the bronchioles partially or completely obliterates the airways.
Signs and symptoms
Bronchiolitis obliterans is a lung disease characterized by fixed airway obstruction. InflammationInflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
and scarring occur in the airways of the lung, resulting in severe shortness of breath and dry cough.
FEV1 (forced expiratory volume in 1 second) should be above 80% of predicted values to be considered normal. Bronchiolitis obliterans reduces this to 16% to 21%.
Symptoms include:
- dry cough
- shortness of breath
- wheezing
The symptoms can start gradually, or severe symptoms can occur suddenly.
Cause
Bronchiolitis obliterans has many possible causes, including: collagen vascular disease, transplant rejectionTransplant rejection
Transplant rejection occurs when transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between donor and recipient and by use of immunosuppressant drugs after...
in organ transplant
Organ transplant
Organ transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...
patients, viral infection (respiratory syncytial virus, adenovirus, HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
, cytomegalovirus
Cytomegalovirus
Cytomegalovirus is a viral genus of the viral group known as Herpesviridae or herpesviruses. It is typically abbreviated as CMV: The species that infects humans is commonly known as human CMV or human herpesvirus-5 , and is the most studied of all cytomegaloviruses...
), Stevens-Johnson Syndrome
Stevens-Johnson syndrome
Stevens–Johnson syndrome and toxic epidermal necrolysis are two forms of a life-threatening skin condition, in which cell death causes the epidermis to separate from the dermis. The syndrome is thought to be a hypersensitivity complex that affects the skin and the mucous membranes...
, Pneumocystis pneumonia
Pneumocystis pneumonia
Pneumocystis pneumonia or pneumocystosis is a form of pneumonia, caused by the yeast-like fungus Pneumocystis jirovecii...
, drug reaction, aspiration and complications of prematurity (bronchopulmonary dysplasia
Bronchopulmonary dysplasia
Bronchopulmonary dysplasia is a chronic lung disorder that is most common among children who were born prematurely, with low birthweights and who received prolonged mechanical ventilation to treat respiratory distress syndrome...
), and exposure to toxic fumes, including: diacetyl
Diacetyl
Diacetyl is a natural byproduct of fermentation. It is a vicinal diketone with the molecular formula C4H6O2...
, sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
, nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
, ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
, thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
, methyl isocyanate
Methyl isocyanate
Methyl isocyanate is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane, methyl carbylamine, and MIC. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides . It has also been used in the production of rubbers and adhesives...
, hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...
, hydrogen bromide
Hydrogen bromide
Hydrogen bromide is the diatomic molecule HBr. HBr is a gas at standard conditions. Hydrobromic acid forms upon dissolving HBr in water. Conversely, HBr can be liberated from hydrobromic acid solutions with the addition of a dehydration agent, but not by distillation. Hydrogen bromide and...
, hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
, hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
, phosgene
Phosgene
Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I. It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles...
, polyamide-amine dyes, mustard gas and ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...
. It can also be present in patients with rheumatoid arthritis. Certain orally administrated emergency medications, such as activated charcoal
Activated carbon
Activated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions.The word activated in the name is sometimes replaced...
, have been known to cause it when aspirated. Additionally, the disorder may be idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
(without known cause).
Industrial inhalants
There are many industrial inhalants that are known to cause various types of bronchiolitis, including bronchiolitis obliterans.Industrial workers who have presented with bronchiolitis:
- 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
Diacetyl (Popcorn workers lung)
Diacetyl
Diacetyl is a natural byproduct of fermentation. It is a vicinal diketone with the molecular formula C4H6O2...
, a chemical used to produce the butter-like flavoring in many foods such as candy, microwave popcorn and wines. This first came to public attention when eight former employees of the Gilster-Mary Lee popcorn plant in Jasper, Missouri
Jasper, Missouri
Jasper is a city in Jasper County, Missouri, United States. The population within the city limits was 931 at the 2010 census. It is part of the Joplin, Missouri Metropolitan Statistical Area.-Geography:Jasper is located at ....
, developed bronchiolitis obliterans. In 2000, the Missouri Department of Health called in NIOSH to make a determination of the cause, and to recommend safety measures. After surveying the plant and each patient's medical history, NIOSH recommended respiratory protection for all workers in microwave popcorn production. Due to this event, bronchiolitis obliterans began to be referred to in the popular media as "Popcorn Lung" or "Popcorn Workers Lung".
One heavy consumer of microwaved popcorn has been diagnosed with this disease, which is the first known case involving a consumer.
On 27 August 2007, Weaver Popcorn Company of Indianapolis
Indianapolis
Indianapolis is the capital of the U.S. state of Indiana, and the county seat of Marion County, Indiana. As of the 2010 United States Census, the city's population is 839,489. It is by far Indiana's largest city and, as of the 2010 U.S...
promised to replace the diacetyl butter flavor ingredient in Pop Weaver popcorn with another flavoring.
In September 2007, Dr. Cecile Rose, pulmonary specialist at Denver's National Jewish Medical and Research Center, warned federal agencies that consumers, not just flavoring or food factory workers, may be in danger of contracting bronchiolitis obliterans. David Michaels, of the George Washington University
George Washington University
The George Washington University is a private, coeducational comprehensive university located in Washington, D.C. in the United States...
School of Public Health, first published Rose's warning letter on his blog.
On 4 September 2007, the Flavor and Extract Manufacturers recommended reduction of diacetyl in butter-like flavorings. The next day ConAgra Foods
ConAgra Foods
ConAgra Foods, Inc. is an American packaged foods company. ConAgra's products are available in supermarkets, as well as restaurants and food service establishments. Its headquarters are located in Omaha, Nebraska...
announced that it would soon remove diacetyl from its popcorn products.
On 16 January 2008, it was announced that Wayne Watson, the Denver consumer who developed "popcorn lung" after inhaling microwaved popcorn, was suing the Kroger
Kroger
The Kroger Co. is an American supermarket chain founded by Bernard Kroger in 1883 in Cincinnati, Ohio. It reported US$ 76.7 billion in sales during fiscal year 2009. It is the country's largest grocery store chain and its second-largest grocery retailer by volume and second-place general retailer...
grocery store chain and its affiliates. In the lawsuit, filed in U.S. District Court, Watson's attorney claimed that the companies "failed to warn that preparing microwave popcorn in a microwave oven as intended and smelling the buttery aroma could expose the consumer to an inhalation hazard and a risk of lung injury."
Diacetyl is approved by the Food and Drug Administration as a safe flavor ingredient, but there is evidence to suggest that inhalation in large amounts is dangerous. There are currently no warnings from federal regulators about diacetyl.
Diagnosis
Bronchiolitis obliterans is often misdiagnosed as asthmaAsthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
, emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
, or pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
.
Diagnosis may include the following tests:
- Chest X-rays tests.
- Diffusing capacity of the lung (DLCODLCODLCO is the extent to which oxygen passes from the air sacs of the lungs into the blood. Commonly, it refers to the test used to determine this parameter. It was introduced in 1909....
) tests are usually normal. - SpirometrySpirometrySpirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
tests show fixed airway obstructions and sometimes restriction. FEV1/FVC may therefore be <75%. - Lung volume tests may show hyperinflation (excessive air in lungs caused by air trappingAir trappingAir trapping, also called gas trapping, is an abnormal retention of air in the lungs where it is difficult to exhale completely. It is observed in obstructive lung diseases such as asthma, bronchiolitis obliterans syndrome and chronic obstructive pulmonary diseases such as emphysema and...
). - High-resolution computerized tomographyTomographyTomography refers to imaging by sections or sectioning, through the use of any kind of penetrating wave. A device used in tomography is called a tomograph, while the image produced is a tomogram. The method is used in radiology, archaeology, biology, geophysics, oceanography, materials science,...
scans of the chest at full inspiration and expiration may reveal heterogeneous air trappingAir trappingAir trapping, also called gas trapping, is an abnormal retention of air in the lungs where it is difficult to exhale completely. It is observed in obstructive lung diseases such as asthma, bronchiolitis obliterans syndrome and chronic obstructive pulmonary diseases such as emphysema and...
on the expiratory view as well as haziness and thickened airway walls. - Lung biopsies may reveal evidence of constrictive bronchiolitis obliterans (i.e., severe narrowing or complete obstruction of the small airways). An open lung biopsy, such as by thoracoscopy, is more likely to be diagnostic than a transbronchial biopsy. Special processing, staining, and review of multiple tissue sections may be necessary for a diagnosis.
Treatment
This disease is irreversible and severe cases often require a lung transplant. Evaluation of interventions to prevent bronchiolitis obliterans relies on early detection of abnormal spirometrySpirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
results or unusual decreases in repeated measurements.
External links
- New England Journal of Medicine Article on CB in Vets
- Dynamics in Healthcare: Information about BOOP/BO and ILD
- National Institutes of Health: Haz-Map Information on Hazardous Chemicals and Occupational Diseases by Jay A. Brown, M.D., M.P.H.: Bronchiolitis obliterans
- National Institute for Occupational Safety and Health (NIOSH) Alert: Preventing lung disease in workers who make or use flavorings
- International Food Information Council (a food industry organization): Questions and Answers about Diacetyl
- A Case of Regulatory Failure: Popcorn Workers' Lung, a case study from www.defendingscience.org
- Is butter flavoring ruining popcorn workers' lungs? By Stephanie Armour, USA TODAY. 2002-06-19.
- National Institute for Occupational Safety and Health: Flavorings-Related Lung Disease
- ConAgra Foods Inc. - Popcorn Facts
- Find out everything about lung disease, symptoms , treating
- German Bronchiolits-Obliterans Forum, exchange of experiences