Extrinsic allergic alveolitis

By hypersensitivity pneumonia (extrinsic allergic alveolitis) is an inflammation of the alveolar sacs and bronsiolelor lung caused by inhalation of dust or chemicals.
First described in 1874 is the inhalation of dust detarminata organic antigens, from different sources: grain, poultry and animals, feathers and down of birds, bird droppings, dust and vapors of water tanks.
Antigens are proteins encountered the bird and thermophilic actinomycetes spores, and the most common lung disease is the farmer.Only a small number of people who inspire those animal products or plant symptoms develop allergic pneumonitis, and a small portion of them will suffer destruction pulmonare.De usually a person must be exposed repeatedly to the allergic reaction occur.
Repeated exposure to antigens initiates a chronic immune response, manifested by increasing white blood cells in alveolar walls and bronhiole.Aceste increases lead finally to the signs and symptoms.
If a person develops hypersensitivity to a specific antigen, in 4-8 hours to install fever, chills, cough, shortness of breath. Trigger contact is interrupted if signs resolve within a few days. In chronic hypersensitivity, in which the person has contact with the antigen for long periods, months, years, irreversible destruction suffering lungs - pulmonary fibrosis.The best prevention is to avoid contact with animal or vegetable products possible allergens, eliminate or reduce dust, wearing masks and good ventiletie the rooms can prevent onset of disease.
People who suffer an episode of pulmonary hypersensitivity to heal in a few days after cessation of antigen exposure, if symptoms are severe, corticosteroids such as prednisone, reduce inflammation and improve the patient's condition.Prolonged and severe episodes can result in irreversible pulmonary fibrosis time.
Pathophysiology
Histologically acute pneumonia hypersensitivity granuloma formation is characterized by interstitial mononuclear infiltration peribronsica.Forma necazeoase and presents in addition to chronic and acute alveolar destruction in honeycomb wax pulmonara.Cristale fibrosis associated with cholesterol are present around the granulomas.
Pathological forms of chronic disease frequently associated with an unfavorable prognosis have three models of fibrosis:-Fibrosis predominantly peripheral-Homogeneous fibrosis-Fibrosis predominantly peribronsiolara nereculata.
Most patients have circulating IgG Ac specific antigen, they react with Ag Ag initially precipitanti.Raspunsul body shape is characterized by increased neutrophils in alveolar walls and small diameter lower airways, followed by an influx of cells releasing enzymes mononucleare.Aceste cells proteolytic, prostaglandins and interleukins leucotriene.Aceasta growth, cytokines, growth factors and other mediators released by T lymphocytes and macrophages play an important role in the pathogenesis of pneumonia.
 Causes
Many types of dust, organisms or chemicals can cause allergic reactions of the lung:-Bacteria in the capitals of fine animal and bird droppings is-Protein livestock-Bacterial contamination of the rooms wetting systems-Chemical-isocyanate-Sawdust-Chemicals used in manufacturing rubber mold, animal fodder, fertilizer plant, plastic materials.