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Hypersensitivity Pneumonitis (HP) By : ziba Loukzadeh, M.D Occupational Medicine department Yazd University of Medical Sciences.

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Presentation on theme: "Hypersensitivity Pneumonitis (HP) By : ziba Loukzadeh, M.D Occupational Medicine department Yazd University of Medical Sciences."— Presentation transcript:

1 Hypersensitivity Pneumonitis (HP) By : ziba Loukzadeh, M.D Occupational Medicine department Yazd University of Medical Sciences

2 Definition Immune (hypersensitive) response Extrinsic allergic alveolitis: granulomatous, interstitial, bronchiolar and alveolar-filling lung diseases caused by repeated exposure and subsequent sensitization to a variety of organic and chemical antigens

3 Etiology Microbial agents Microbial agents Animal proteins Animal proteins Low molecular weight chemicals Low molecular weight chemicals

4 Microbial agents Bacteria Bacteria -Farmer’s lung -Farmer’s lung -Bagassosis -Bagassosis -Mushroom worker’s lung -Mushroom worker’s lung Fungi Fungi -Wood pulp worker’s lung -Wood pulp worker’s lung -Cheese washer lung -Cheese washer lung Ameba Ameba -Humidifier lung -Humidifier lung

5 Bacteria cause causeoccupation Agent Agent source source Major Major antigen antigen Farmer's lung Agriculture worker Moldy hay thermoactinomycet Mushroom worker's Mushroom worker Compostthermoactinomycet Bagassosis Bagass worker Moldysugarcanethermoactinomycet

6 Animal proteins Avian proteins : Bird breeder’s lung Avian proteins : Bird breeder’s lung Urine,Serum,Pelts : Animal handler’s lung Urine,Serum,Pelts : Animal handler’s lung Wheat weevil : Wheat weevil lung Wheat weevil : Wheat weevil lung

7 Chemicals Isocyanate HP Isocyanate HP TDI, MDI, HDI TDI, MDI, HDI TMA HP TMA HP Trimellitic anhydride Trimellitic anhydride

8 Pathogenesis Immunology Immunology Repeated inhalation of antigens Repeated inhalation of antigens sensitization immunology response(type III,IV) influx of neutrophiles shift T lymphocytes (~70%)(predominantly of CD8) Antibodies in HP are IgG class Antibodies in HP are IgG class Response delay by 3-8 hours Response delay by 3-8 hours

9 Pathogenesis (cont’) Host factors Host factors -Non smokers > smokers -Non smokers > smokers -Polymorphism in TNF-α gene -Polymorphism in TNF-α gene -No association with HLA -No association with HLA

10 Pathogenesis (cont’) Exposure factors: Exposure factors: -Ag concentration -Ag concentration -Duration of exp. -Duration of exp. -Frequency & intermittency of exp. -Frequency & intermittency of exp. -Particle size -Particle size -Use of respiratory protection -Use of respiratory protection Farmer's lung disease: winter Bird breeder's lung: summer Indirect exposure

11 Clinical features Acute HP : fever,chill,myalgia,cough & dyspnea + basilar rales in Ph/E (4-12 h after heavy exp. ) Acute HP : fever,chill,myalgia,cough & dyspnea + basilar rales in Ph/E (4-12 h after heavy exp. ) Recurrent febrile episodes (most frequent presentation) Subacute & chronic HP : insidious onset of respiratory symptoms,malaise, fatigue, weight loss + basilar rales,wheezing cyanosis,right sided HF in Ph/E Subacute & chronic HP : insidious onset of respiratory symptoms,malaise, fatigue, weight loss + basilar rales,wheezing cyanosis,right sided HF in Ph/E

12 DDx Inhalation fevers Inhalation fevers others granulomatous disorder(Sarcoidosis) others granulomatous disorder(Sarcoidosis) immunologic disease (Asthma) immunologic disease (Asthma) infection infection fibrotic lung disease (IPF) fibrotic lung disease (IPF)

13 Comparison HP& Inhalation fever Feature HP HP Inhalation fever Inhalation fever Example Farmer`s lung disease Metal fume fever EtiologyThermoactinomyces Zinc fume fever pathophysiology Hypersensitive reaction Cytokine- mediated (??) Exposure dose Low dose High dose Sensitization required YesNo

14 Comparison HP& Inhalation fever (cont´) Feature HP HP Inhalation fever Inhalation fever FeverYesYes Flu-like syndrome YesYes CoughExpected Not necessary DyspneaYes Not typically Chest exam Ralesnormal

15 Comparison HP& Inhalation fever (cont´) Feature HP HP Inhalation fever Inhalation fever CXR Alveolar infiltration No PFT Decreased DLCO&volums Minimal change BALLymocytosis Inincreased Neutrophiles Chronic sequle ~yesNone Natural Hx Reccurent or progressive Complete recovery within 3 day

16 Lab. studies Precipitin Ab: Precipitin Ab: Helpful but not specific, not sensitive, not hallmark Helpful but not specific, not sensitive, not hallmark Leukocytosis,mild elevation of ESR,CRP, IgG, IgA,IgM,ACE,ANA Leukocytosis,mild elevation of ESR,CRP, IgG, IgA,IgM,ACE,ANA

17 PFT Normal (early dis.) Normal (early dis.) Restrictive Restrictive Obstructive Obstructive Mixed Mixed decreased DLCO (most sensitive physiologic test in early HP ) decreased DLCO (most sensitive physiologic test in early HP )

18 CXR Acute : diffuse ground glass,fine nodular or reticulonodular pattern (lower lung ) Acute : diffuse ground glass,fine nodular or reticulonodular pattern (lower lung ) Subacute : reticulonodular pattern Subacute : reticulonodular pattern Chronic : fibrosis,reticular opacity, honey combing Chronic : fibrosis,reticular opacity, honey combing mediastinal lymphadenopathy (up to 50%) mediastinal lymphadenopathy (up to 50%)

19 HRCT Ground glass Ground glass Centrilobular nodules Centrilobular nodules Airspace consolidation Airspace consolidation Mosaic patten Mosaic patten Fibrosis Fibrosis Emphysema Emphysema

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21 Normal CXR

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28 Histopathology Classic triad : Classic triad : cellular bronchiolitis cellular bronchiolitis lymphoplasmocytic interstitial infiltration lymphoplasmocytic interstitial infiltration non-necrotizing granuloma non-necrotizing granuloma

29 diagnosis Temporal relationship between symptoms and certain activities is often the first clue to the diagnosis of HP Temporal relationship between symptoms and certain activities is often the first clue to the diagnosis of HP

30 diagnosis environmental history: environmental history: pets and other domestic animals pets and other domestic animals hobbies such as gardening and lawn care hobbies such as gardening and lawn care recreational activities, for example, use of hot tubs and indoor swimming pools recreational activities, for example, use of hot tubs and indoor swimming pools use of humidifiers, cool mist vaporizers, and humidified air conditioners use of humidifiers, cool mist vaporizers, and humidified air conditioners moisture indicators such as leaking, flooding, or previous water damage to carpets and furnishings moisture indicators such as leaking, flooding, or previous water damage to carpets and furnishings

31 Diagnostic criteria Required Required appropriate exposure appropriate exposure dyspnea on exertion dyspnea on exertion inspiratory crackles inspiratory crackles lymphocytic alveolitis lymphocytic alveolitis Supportive recurrent febrile episodes infiltrative on CXR decreased DLCO precipitating antibodies granulomatous on lung biopsy improvement with contact avoidance

32 Treatment Best treatment : Removal from exp. Best treatment : Removal from exp. Preferred approach : Elimination of Ag. Preferred approach : Elimination of Ag. Oral corticosteroid : in severe or progressive disease Oral corticosteroid : in severe or progressive disease O2,inhaled steroid & B-agonist in airflow limitation O2,inhaled steroid & B-agonist in airflow limitation

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