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Extrinsic allergic alveolitis (hypersensitivity pneumonitis, EAA)

Extrinsic allergic alveolitis (hypersensitivity pneumonitis, EAA). Immunologically mediated inflammatory reaction in the alveoli and in the respiratory bronchioles

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Extrinsic allergic alveolitis (hypersensitivity pneumonitis, EAA)

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  1. Extrinsic allergic alveolitis(hypersensitivity pneumonitis, EAA) • Immunologically mediated inflammatory reaction in the alveoli and in the respiratory bronchioles • causes: organic dusts (<5µm) moulds foreign proteins some chemicals diisocyanates organic acid anhydrides • often heavy, repeated exposure, most often at the work place hkes03

  2. EAA • Pathology: Granulomatotic inflammation around the alveoli and the peripheral bronchioles.Exudate with plasma cells and lymphocytes.Macrophages, epitheloid cells and giant cells in the granulomas in the middle of the inflammation process. • After the exposure ceases the reaction disappeares in 3-4 months. • If the exposure continues, the exudation organises into fibrine and an irreversible pulmonary fibrosis follows.

  3. Examples of EAA Etiology • Farmer's lung mouldy hay • Saw mill worker's lung mouldy wood dust • Bird fancier's lung proteins in bird droppings • Mushroom worker´s lung spores, moulds • Malt worker´s lung mouldy malt • Humidifier lung contaminated humidifier water • Cheese washer's lung Penicillium casei • Suberosis cork dust mould • Diisocyanate lung polyurethane hardeners • Hard metal worker's lung hard metal dust, cobalt

  4. Allergic alveoltis in Finland 1981-2001(Finnnish Register of Occupational Diseases)

  5. SRR (standardized risk ratio) of EAA in some occupations Occupation SRR n farmers and cattle tenders 9.2 (8.4-10) 928 other printing workers 5.2 (2.2-13) 5 bookbindery workers 4.4 (1.7-5) 7 printers 4.1 (2.2-7.7) 10 wood workers 2.9 (1.3-4.6) 13 typesetters 2.4 (1.3-4.6) 10 Keskinen et al. Työperäiset hengtystieallergiat. Jauhoastmasta sementti-ihottumaan.Työterveyslaitos, Helsinki 1997

  6. EAA, symptoms • flu-like illness • cough • high fever, chills • dyspnea, chest tightness • malaise, myalgia4-8 hours after exposure • chronic disease: dyspnea in strain, sputum production, fatigue, anorexia, weight loss

  7. EAA, clinical findings • Status dyspnea, cyanosis, crepitant rales digital glubbing (chronic form) • Chest X-ray normal or small nodules/diffuse infiltrates/ ground glass appearance chronic form: pulmonary fibrosisHRCT normal or ground glass appearance centrilobular micronodules • lung function restriction, diffusing capacity decreases, hypoxemia, obstruction, hyperreactivity • lab. tests rise of sedimentation rate, leukocytosis, neutrophilia • BAL marked lymphocytosis, T helper / T supressor cells decreased

  8. EAA: HRCT, acute disease

  9. EAA: HRCT, chronic disease

  10. Diagnostics of EAA • Main criteria1. Exposure to arganic dust (history, spesific IgG antibodies, work place measurements).2. Typical symptoms3. Chest X-ray findings • Additional criteria1. Decreased diffusion capacity3. Hypoxia during rest or decreasing during excercise4. Restriction in spirometric values5. Lung biopsy with findings of allergic alveolitis6. Provocation test (at work place) positiveAll main criteria and two of the additional ones are needed for diagnosis. (Terho, Keuhkosairaudet, Duodecim 20

  11. EAA, differential diagnostics • Organic Dust Toxic Syndrome (ODTS) • Sarcoidosis • Drug-induced pneumonitis • Viral and mycoplasma pneumonias • Tuberculosis • Allergic bronchopulmonary aspergillosis • Collagen-vascular diseases • Lymphangitis carcinomatosa • Pulmonary fibrosis (DIP) • Pneumoconioses

  12. EAA, treatment • Stopping of exposure • Oral steroids • Farmer's lung: after recovery back to work excluding/minimizing the exposure • motorized respiratory ventilator, training! • after reorganization of the job description • follow-up

  13. EAA, prognosis • Continuing exposure, relapsing disease leads to pulmonary fibrosis, permanent loss of pulmonary function and cor pulmonale. • When Finnish cases with farmer's lung were followed for 10 years, 23% had findings of pulmonary emphysema or pulmonary fibrosis.

  14. EAA, prevention • reduction of dust exposure • work hygienic improvements • adequate respirators always during exposure- before any symptoms! • occupational health care • information • follow-up • finding symptomatic workers in time, to prevent permanent loss of pulmonary function

  15. Organic Dust Toxic Syndrome (ODTS) • opening of silos pulmonary mycotoxicosis • exposure to grain grain fever • 1986 diPico ODTS • Etiology: heavy exposure to biological organic dustsmycotoxins and endotoxins • No sensitization • No latency time • prevalence numbers farmers 14% mushroom cultivation 37%

  16. ODTS • Symptoms: • fever, main symptom • cough • irratative symptoms of mucous membranes • fatigue • myalgia • Symptoms mild to severe, ceasing when no exposure • Symptoms milder than in allergic alveolitis • No chronic form?

  17. ODTS, diagnostics • Criteria not yet clear • Investigated as allergic alveolitis • Exposure and timing of symptoms important, often a few hours after exposure. • No findings in chest X-ray • lung function: normal or as in EAA but mild • BAL: neutrophilia? • Work place provocation test following symptoms, temperature, diffusion capacity and FEV1/PEF

  18. Differential Diagnostics: Extrinsic allergic alveolitis (EAA)/Asthma(OA)/ODTS Feature EAA OA ODTS Symptoms Cough, dyspnea Cough, dyspnea Flu-like symptoms fever fever Onset after exposure Gradual after 4-8h Immediate or Gradual after 3-8h late Physical findings Bibasil. crackles Expirat. wheezes None Chest X-ray Infiltrates/norm. Normal Normal Lung function Restrictive Obstructive Normal? Peripheral eosinophilia No Yes? No

  19. Conclusion • Farmer´s lung is the most usual extrinsic allergic alveolitis. Chronic form leads to severe disability. • Reduction of the exposure to biological dust by work hygienic improvements and using adequate respirators is important. The humidifiers and other sources of exposure should be cleaned. • Early recognition of the symptoms is essential. • ODTS is a milder syndrome, symptoms can be prevented using respirator when exposed.

  20. Literature • Pickering CAC, Newman Taylor AJ. Extrinsic allergic bronchioloalveolitis (hypersensitivity pneumonia). In RW Parkes, Occupational Lung Disorders, Third edition1994, Butterworth Heineman Ltd, UK, • Terho EO. Orgaanisten pölyjen aihettamat keuhkokudoksen yliherkkyysreaktiot. Kirjassa Allergologia, toim. Haahtela T, Hannuksela M, Terho E.O. Kustannusosakeyhtiö Duodecim, 1999:391-403. • Terho EO. Allerginen alveoliitti ja sitä muistuttavat sairaudet. Kirjassa Keuhkosairaudet, toim. Kinnula V. Laitinen L.A.L, Tukiainen P. Kustannusosakeyhtiö Duodecim, 2000:336-342.

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