Byssinosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Byssinosis is a disease of the lungs brought on by breathing in cotton dust or dusts from other vegetable fibers such as flax, hemp, or sisal while at work.

Hypersensitivity pneumonitis (HP), also called extrinsic allergic alveolitis (EAA), is not a single disease but is a complex syndrome of varying intensity, clinical presentation, and natural history.

Synonyms and keywords: Hypersensitivity pneumonitis, HP, bird fancier’s lung, extrinsic allergic alveolitis, farmer’s lung, Saccharopolyspora rectivirgula, S rectivirgula, Micropolyspora faeni, M faeni, Thermoactinomyces sacchari, T sacchari, Thermoactinomyces vulgaris, T vulgaris, Penicillium casei, P casei, Aspergillus clavatus, A clavatus, Mucor stolonifer, M stolonifer, Sitophilus granarius, S granarius, Cladosporium, heykatarr, bagassosis, grain handler’s lung, humidifier lung, air-conditioner lung, bird breeder’s lung, cheese worker’s lung, malt worker’s lung,paprika splitter’s lung, mollusk shell hypersensitivity, chemical worker’s lung, pulmonary disease, lung disease.

The syndrome was first described in Iceland in 1874 and termed heykatarr.

The syndrome is caused by sensitization to repeated inhalation of dusts containing one of 300 organic antigens. These organic dusts come from a wide variety of sources but most commonly include:

• Dairy and grain products
• Animal dander and protein
• Wood bark
• Water reservoir vaporizers

The two most common antigens are:

1. Thermophilic actinomycetes and
2. Avian proteins

As a rseult of exposure to thee antigens, the two most common causes (i.e. diseases) are:

1. Farmer’s lung and
2. Bird fancier’s lung

• [Disease name] may be caused by either [cause1], [cause2], or [cause3].
• [Disease name] is caused by a mutation in the [gene1], [gene2], or [gene3] gene[s].
• There are no established causes for [disease name].

• [Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:

• [Differential dx1]
• [Differential dx2]
• [Differential dx3]

• The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
• In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

• Patients of all age groups may develop [disease name].

• [Disease name] is more commonly observed among patients aged [age range] years old.
• [Disease name] is more commonly observed among [elderly patients/young patients/children].

• [Disease name] affects men and women equally.

• [Gender 1] are more commonly affected with [disease name] than [gender 2].
• The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

• There is no racial predilection for [disease name].

• [Disease name] usually affects individuals of the [race 1] race.
• [Race 2] individuals are less likely to develop [disease name].

• Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

• The majority of patients with [disease name] remain asymptomatic for [duration/years].
• Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
• If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
• Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
• Prognosis is generally [excellent/good/poor], and the [1/5/10­year mortality/survival rate] of patients with [disease name] is approximately [#%].

• The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met:

• [criterion 1]
• [criterion 2]
• [criterion 3]
• [criterion 4]

• [Disease name] is usually asymptomatic.
• Symptoms of [disease name] may include the following:

• [symptom 1]
• [symptom 2]
• [symptom 3]
• [symptom 4]
• [symptom 5]
• [symptom 6]

• Patients with [disease name] usually appear [general appearance].
• Physical examination may be remarkable for:

• [finding 1]
• [finding 2]
• [finding 3]
• [finding 4]
• [finding 5]
• [finding 6]

• There are no specific laboratory findings associated with [disease name].

• A [positive/negative] [test name] is diagnostic of [disease name].
• An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
• Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

• There are no [imaging study] findings associated with [disease name].

• [Imaging study 1] is the imaging modality of choice for [disease name].
• On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
• [Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

• [Disease name] may also be diagnosed using [diagnostic study name].
• Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

• There is no treatment for [disease name]; the mainstay of therapy is supportive care.

• The mainstay of therapy for [disease name] is [medical therapy 1] and [medical therapy 2].
• [Medical therapy 1] acts by [mechanism of action 1].
• Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].

• Surgery is the mainstay of therapy for [disease name].
• [Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of [disease name].
• [Surgical procedure] can only be performed for patients with [disease stage] [disease name].

• There are no primary preventive measures available for [disease name].

• Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].

• Once diagnosed and successfully treated, patients with [disease name] are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The syndrome was first described in Iceland in 1874 and termed heykatarr.

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

There are noncaseating interstitial granulomas and mononuclear cell infiltration in a peribronchial distribution. Giant cells are prominent.

The noncaseating granulomas are more well formed. There is bronchiolitis with or without organizing pneumonia. Interstitial fibrosis is present.

There is chronic interstitial inflammation and alveolar destruction (honeycombing). There is dense fibrosis. The pathologic findings of chronic HP that are often associated with a poorer prognosis include the following 3 patterns of fibrosis:

• Predominantly peripheral fibrosis: in a patchy pattern with architectural distortion and fibroblast foci similar to usual interstitial pneumonia (UIP)

• Homogeneous linear fibrosis: similar to fibrotic nonspecific interstitial pneumonia (NSIP)

• Irregular predominantly peribronchiolar fibrosis

Exposure results in the development of circulating immunoglobulin G antibodies that are specific for the offending antigen. This antibody that forms is called the precipitating antibody, and it reacts with the specific putative antigen to form a precipitant. Initially the disease process was thought to be immunecomplex-mediated. However, subsequent studies have demonstrated that cell-mediated immunity is more important.

In the acute phase, there is a local increase in neutrophils in the alveoli and small airways. This is followed by an influx of mononuclear cells which release proteolytic enzymes, prostaglandins, and leukotrienes.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Hypersensitivity pneumonitis usually occurs in people who work in places where there are high levels of organic dusts, fungus, or molds. Bird fancier’s lung is the most common type of hypersensitivity pneumonitis. It is caused by repeated or intense exposure to proteins found in the feathers or droppings of many species of birds.

Farmer’s lung is caused by exposure to dust from moldy hay, straw, and grain. These exposures can lead to lung inflammation and acute lung disease. Over time, this acute Hypersensitivity pneumonitis may turn into long-lasting (chronic) lung disease.

Hypersensitivity pneumonitis may also be caused by fungi or bacteria in humidifiers, heating systems, and air Hypersensitivity pneumonitisers found in homes and offices. Exposure to certain chemicals, such as isocyanates or acid anhydrides, can also lead to hypersensitivity pneumonitis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The differential diagnosis of hypersensitivity pneumonitis is, primarily, a group of diseases known as idiopathic interstitial pneumonias. This group of diseases includes idiopathic pulmonary fibrosis (IPF) (which manifests histologically as usual interstitial pneumonia (UIP)), idiopathic non-specific interstitial pneumonia (NSIP) and cryptogenic organizing pneumonia, among others. There are several important clinical syndromes that occur as a result of inhalation of organic agents but are not true forms of Hypersensitivity Pneumonitis.

Other diseases that are secondary to inhalation of organic agents but are not true forms of HP are as follows:

1. Inhalation fever: Patients present with fever, chills, headache, and myalgias however there are not pulmonary findings (although mild dyspnea may occur). Onset is 4-8 hours following exposure. There are no long-term sequelae occur.
2. Organic dust toxic syndrome: This syndrome is the result of exposure to bioaerosols contaminated with toxin-producing fungi (mycotoxins). Patients present with fever, chills, and myalgias 4-6 hours after exposure. In contrast to inhalation fever, the chest X ray may show diffuse opacities. Bronchiolitis or diffuse alveolar damage may be present on lung biopsy specimens. This is not a true form of HP because no prior sensitization is required.
3. Chronic bronchitis: This can result from chronic obstructive pulmonary disease, which is the most common respiratory syndrome among agricultural workers. The prevalence of chronic bronchitis is much higher at 10%, compared with 1.4% for HP.
4. Exposure to aerosolized Mycobacterium avium complex (MAC): A hypersensitivity pneumonitis like syndrome has been described in patients exposed to aerosolized Mycobacterium avium complex (MAC). Hot tub lung is a term used to describe these hypersensitivity pneumonitis-like cases because they have generally been associated with hot tub use. The syndrome has been linked to the high levels of infectious aerosols containing MAC organisms found in the water. Whether this syndrome represents a true MAC infection or classic HP remains controversial (Marras, 2005).

By frequency of Interstitial Lung Diseases (Xaubet, 2004):

1. Idiopathic pulmonary fibrosis (38.6%)
2. Sarcoidosis (14.9%)
3. Cryptogenic organizing pneumonia (10.4%)
4. Interstitial lung disease associated with collagen vascular diseases (9.9%)
5. Hypersensitivity Pneumonitis (HP) (6.6%)
6. Unclassified (5.1%)

In alphabetical order:

• Air-conditioner lung
• Aspergillus clavatus
• Bagassosis
• Bird breeder’s lung
• Bird fancier’s lung
• Cheese worker’s lung
• Chemical worker’s lung
• Cladosporium
• Farmer’s lung
• Grain handler’s lung
• Humidifier lung
• Malt worker’s lung
• Micropolyspora faeni
• Mollusk shell hypersensitivity
• Mucor stolonifer
• Paprika splitter’s lung
• Penicillium casei
• Saccharopolyspora rectivirgula
• Sitophilus granarius
• Thermoactinomyces sacchari
• Thermoactinomyces vulgaris

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Hypersensitivity pneumonitis usually occurs in people who work in places where there are high levels of organic dusts, fungus, or molds. As the causative agent is dust, the prevalence of HP varies significantly by region, climate, occupation/exposure and farming practices.

• Farmers:
  • US: 8-540 cases per 100,000 persons per year among those at risk
  • UK: 420-3000 cases per 100,000 persons per year among those at risk
  • France: 4370 cases per 100,000 persons per year among those at risk
  • Finland: 1400-1700 cases per 100,000 persons per year among those at risk

• Pigeon Breeders: 6000-21,000 cases per 100,000 persons per year

• Bird Fanciers: 20-20,000 cases per 100,000 persons per year

• Attack rates vary considerably, but can be high in sporadic outbreaks. For example a large proportion (52%) of office workers exposed to an infected humidifier were affected in one outbreak, and in another outbreak 27% of workers at a molding plant for polyurethane foam parts were affected.

Males are slightly more affected, The male to female ratio being approximately 1.2:1.

It generally occurs in patient with fourth and fifth decade of there life. The mean age of the patients with HP is 61 ± 0.7 years. ^[1]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The following is a partial list of occupations and major causative antigens that put a patient at risk of HP. Microbial agents like fungi or bacteria in humidifiers, heating systems, and air conditioners found in homes and offices. Exposure to certain chemicals, such as isocyanates or acid anhydrides, can also increase the risk of hypersensitivity pneumonitis in susceptible individuals.

1. Farmers and cattle workers: These workers develop the most common form of HP which is caused by the antigen thermophilic actinomycetes. It is important to note that while Farmer’s lung is the most common cause of HP, it still must be distinguished from febrile toxic reactions to inhaled mold dusts (organic dust toxic syndrome, a nonimmunologic reaction) which occurs 30-50 times more often than HP.
2. Poultry and other bird handlers: These workers are exposed to droppings, feathers, and serum proteins of pigeons and other birds.
3. Ventilation workers and those exposed to water-related contamination: These workers may be exposed to microorganisms thatcolonize humidifiers, forced-air systems, hot tubs, whirlpools, and spas. The putative antigens are derived from Thermoactinomyces or Cladosporium.
4. Veterinarians and animal handlers: These workers obviously have daily contact with a large variety of animals and organic antigens.
5. Grain and flour processors and loaders: These workers are exposed to grain. Grain can become colonized with a variety of microorganisms and their antigens.
6. Lumber mill workers and paper and wallboard manufacturers: These workers are exposed to wood which can become colonized with molds and then becomes aerosolized.
7. Plastic manufacturers, painters, and electronics industry workers: These workers can be exposed to diphenylmethane diisocyanate or toluene diisocyanate.
8. Textile workers: These workers do develop lung injury but this is not a true form of HP. The injury is characterized by diffuse alveolar damage or airway dysfunction and includes diseases such as byssinosis and nylon worker’s lung.

Hypersensitivity Pneumonitis (HP) may also be called many different names, based on the provoking antigen. These include:

1. Bird-Breeder’s Lung : Also called Bird fancier’s lung, Pigeon-Breeder’s Lung, and Poultry-Worker’s Lung. Caused by avian proteins. Exposure is from feathers and bird droppings.

Farmer’s Lung

Caused by the molds Thermophilic actinomycetes, Aspergillus species, Saccharopolyspora rectivirgula, and Micropolyspora faeni. Exposure is generally from moldy hay but may be found elsewhere.

Bagassosis

Caused by Thermophilic actinomycetes. Exposure is from moldy bagasse (pressed sugarcane).

Malt Worker’s Lung

Caused by Aspergillus clavatus. Exposure is from moldy barley.

Humidifier Lung

Caused by the bacterias T. candidus, Bacillus subtilis, B. cereus, and Klebsiella oxytoca; the fungus Aureobasidium pullulans; and the amoebae Naegleria gruberi, Acanthamoeba polyhaga, and Acanthamoeba castellani. Exposure is from mist from standing water.

Mushroom Worker’s Lung

Caused by Thermophilic actinomycetes. Exposure is from mushroom compost.

Compost Lung

Caused by Aspergillus. Exposure is from compost.

Peat Moss Worker’s Lung

Caused by Monocillium sp. and Penicillium citreonigrum. Exposure if from peat moss.

Suberosis

Caused by Penicillum frequentans. Exposure is from moldy cork dust.

Japanese Summer-Type HP

Caused by Trichosporon cutaneum. Exposure is from damp wood and mats.

Cheese-Washer’s Lung

Caused by Pencillum casei or P.roqueforti. Exposure is from cheese casings.

Metalworking Fluids HP

Caused by Nontuberculous Mycobacteria. Exposure is from mist from metalworking fluids.

Hot Tub Lung

Caused by Mycobacterium avium complex. Exposure is from mist from hot tubs.

Mollusc Shell HP

Caused by aquatic animal proteins. Exposure is from mollusc shell dust.

Isocyanate HP

Caused by TDI, HDI, and MDI. Exposure is from paints, resins, and polyurethane foams.

TMA HP

Caused by Trimellitic anhydride. Exposure is from plastics, resins, and paints.

Berylliosis

Caused by Beryllium. Exposure in the electronics industry.

Wine-grower’s lung

From Botrytis cinerea mold on grapes.

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Most patients experience total recovery of lung function, if exposure to the agent that caused the problem is avoided or limited the exposure, but this takes several years.

• In general, the majority of patients recover completely after the inciting exposure ceases.

• The prognosis of Bird Fancier’s Disease is worse than Farmer’s Lung.
• Other varieties of HP have more variable outcomes.

The chronic form of this disease may lead to pulmonary fibrosis (a scarring of the lung tissue that often is not reversible).