Presentation on theme: "Extrinsic allergic alveolitis (hypersensitivity pneumonitis, EAA) Immunologically mediated inflammatory reaction in the alveoli and in the respiratory."— Presentation transcript:
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
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.
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 lungPenicillium casei Suberosiscork dust mould Diisocyanate lungpolyurethane hardeners Hard metal worker's lunghard metal dust, cobalt
Allergic alveoltis in Finland (Finnnish Register of Occupational Diseases)
SRR (standardized risk ratio) of EAA in some occupations OccupationSRRn farmers and cattle tenders9.2 (8.4-10)928 other printing workers 5.2 (2.2-13)5 bookbindery workers4.4 (1.7-5)7 printers4.1 ( )10 wood workers2.9 ( )13 typesetters2.4 ( )10 Keskinen et al. Työperäiset hengtystieallergiat. Jauhoastmasta sementti- ihottumaan.Työterveyslaitos, Helsinki 1997
EAA, symptoms flu-like illness cough high fever, chills dyspnea, chest tightness malaise, myalgia 4-8 hours after exposure chronic disease: dyspnea in strain, sputum production, fatigue, anorexia, weight loss
EAA, clinical findings Status dyspnea, cyanosis, crepitant rales digital glubbing (chronic form) Chest X-raynormal or small nodules/diffuse infiltrates/ ground glass appearance chronic form: pulmonary fibrosis HRCT normal or ground glass appearance centrilobular micronodules lung functionrestriction, diffusing capacity decreases, hypoxemia, obstruction, hyperreactivity lab. testsrise of sedimentation rate, leukocytosis, neutrophilia BAL marked lymphocytosis, T helper / T supressor cells decreased
EAA: HRCT, acute disease
EAA: HRCT, chronic disease
Diagnostics of EAA Main criteria 1. Exposure to arganic dust (history, spesific IgG antibodies, work place measurements). 2. Typical symptoms 3. Chest X-ray findings Additional criteria 1. Decreased diffusion capacity 3. Hypoxia during rest or decreasing during excercise 4. Restriction in spirometric values 5. Lung biopsy with findings of allergic alveolitis 6. Provocation test (at work place) positive All main criteria and two of the additional ones are needed for diagnosis. (Terho, Keuhkosairaudet, Duodecim 20
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
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.
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
opening of silos pulmonary mycotoxicosis exposure to grain grain fever 1986 diPico ODTS Etiology: heavy exposure to biological organic dusts mycotoxins and endotoxins No sensitization No latency time prevalence numbers farmers14% mushroom cultivation 37% Organic Dust Toxic Syndrome (ODTS)
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?
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
Differential Diagnostics: Extrinsic allergic alveolitis (EAA)/Asthma(OA)/ODTS FeatureEAAOAODTS SymptomsCough, dyspneaCough, dyspneaFlu-like symptoms feverfever Onset after exposureGradual after 4-8hImmediate orGradual after 3-8h late Physical findingsBibasil. crackles Expirat. wheezesNone Chest X-rayInfiltrates/norm.NormalNormal Lung functionRestrictiveObstructiveNormal? Peripheral eosinophiliaNoYes?No
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.
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: Terho EO. Allerginen alveoliitti ja sitä muistuttavat sairaudet. Kirjassa Keuhkosairaudet, toim. Kinnula V. Laitinen L.A.L, Tukiainen P. Kustannusosakeyhtiö Duodecim, 2000: