Extrinsic allergic alveolitis Hypersensitvity pneumonitis ???????????????????

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Extrinsic allergic alveolitisHypersensitvity
pneumonitis???????????????????

• ?.?.?. ???? ????
• ??????????????????????????
• ????????????????

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HP Introduction

• immunologically induced lung disease
• diffuse inflammation of lung parenchyma airways
  in previously sensitized patients
• sensitized to repeated inhalation of dusts
  containing organic low molecular weight
  chemical antigens

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HP Introduction

• dusts derived from
• dairy grain products
• animal dander proteins
• wood bark
• water reservoir vaporizers
• not atopic disease
• not associated with increase IgE or eosinophils

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HP Selected etiological agents
Disease Farmers lung ????????? Bagassosis ???????
??? Bird-breeders lung Bird-fanciers
lung Pigeon-breeders lung Mushroom-workers
lung ?????????? Humidifier/air conditioner lung ??
?????????????????? ????????????????? ?????
Source ????????????????? ???????????????? ?????,
?? (?????,??????) ?????????????,???????? ??????
??????????? ???????????????????
Antigen Micropolyspora faeni Thermoactinomyces
sacchari Avian proteins Thermoactinomyces
vulgaris Micropolyspora faeni Thermoactinomyces
vulgaris
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HP Epidemiology

• Varies
• 0.5-5 of farmers (Farmers lung disease)
• 8-30 of members of pigeon breeding clubs
  (pigeon breeders disease)
• Prevalence Farmers lung

UK France Finland U.S.A.
420-3000 4370 1400-1700 540
cases/100,000 /
persons at
risk
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Bagassosis A Report of 8 Cases
?????????????????? 251757468-74.

• Pee Kamtorn, M.D.
• Poonkasem Charoenpan, M.D.
• Yosvi Sukumalchantra, M.D. ,
  F.A.C.P. , F.R.C.P. (C) ,F.A.C.C.
• Vijitr Boonpucknavig, M.D.
• Kalyanakit Kitiyakara, M.B. , B.S. ,
  M.R.C.S. , L.R.C.P.
• Chirotchana Suchato, M.D.
• Chaivej Nuchprayoon, M.D.
• Bagassosis is classified as an extrinsic
  allergic
• pneumonia. It is considered to be the
  result of
• allergic reaction to moldy sugar cane
  inhalation(1) .

Case Report All of the patients worked at
a paper produc- tion factory in Karnchanaburi
province and were
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HP Pathogenesis

• immune - complex mediated process
• precipitating Ab against specific Ag
• 50 of asymptomatic persons exposed also have Ab

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HP Pathogenesis

• cell - mediated immunity more important
• response
• increase PMN in alveoli small airways
• influx of mononuclear cells
• formation of granulomas
• cytokine from T- lymphocytes macrophages

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HP Histologic findings

• diffuse interstitial infiltrate lymphocytes,
  macrophages, mast cells, plasma cells
• scattered noncaseating granulomas
• cellular inflammation of bronchioles,
  bronchiolar obstruction
• absent generalized vasculitis, necrotizing
  granulomata
• duration or stage of disease, adequacy of
  biopsy sample

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HP Diagnostic criteria

• Major criteria
• 1. Symptoms c/w HP , appear or worsens within
  hours after Ag exposure
• 2. Confirmation of exposure to the offending
  agent by
• - Hx
• -investigation of the environment
• -serum precipitin test
• -BAL Ab

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HP Diagnostic criteria

• 3. Compatible CXR or HRCT
• 4. Lymphocytosis in BAL
• 5. Compatible histologic changes
• 6. Positive natural challenge or by
  controlled inhalational challenge

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HP Diagnostic criteria

• Minor criteria
• 1. Basilar crackles
• 2. Decreased diffusion capacity
• 3. Arterial hypoxemia, at rest or with exercise

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HP Diagnostic criteria

• Four major criteria
• Two minor criteria
• Other diseases have been excluded
• Adapted from Schuyler Cormier Chest 1997 111
  534-6.

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HP Diagnosis

• often unrecognized misdiagnosed
• respiratory symptoms with Hx. of
• environmental
• occupational exposure
• respiratory symptoms with episodic radiographic
  infiltrates Recurrent pneumonia

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HP Radiographic findings

• vary to the stage of disease
• acute HP
• bilateral micronodular (1-4 mm.) infiltrates
• patchy ground-glass opacities
• decreased attenuation (air trapping from
  bronchiolitis) and mosaic pattern
  (expiratory view)

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HP Radiographic findings

• Subacute HP
• fine linear shadows, small nodules
  reticulonodular appearance
• Chronic HP
• volume loss
• reticulonodular infiltrates
• honeycombing
• predominantly upper mid lung zones

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HP Pulmonary function tests

• restrictive changes
• (superimposed obstruction in chronic HP)
• decreased diffusing capacity
• ABG increased alveolar-arterial oxygen
  gradient
• frank hypoxemia (severe cases)
• oxygen desat. with exercise (clue in
  suspected case)

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HP BAL fluid

• intense lymphocytosis
• predominantly CD 8 T-suppressor cells
• timing of the last antigen exposure, stage of
  disease

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HP key features
Immunopathology alveolitis, immune
complex granulomas, bronchiolitis lymphocytic
infiltration, fibrosis,air space destruction
Prognosis good good good
Time frame 4-48 hr weeks to 4 M. 4 M. to years
Acute Subacute Chronic
Clinical features fever, chills, cough hypoxemia,
aches dyspnea , cough, episodic flares dyspnea,
cough, fatigue, weight loss
HRCT ground glass infiltrates micronodules, air
trapping fibrosis, honey combing, emphysema

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HP Differential diagnosis

• Acute stage
• pneumonia
• acute tracheobronchitis
• organic dust toxic syndrome
• BOOP

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HP Differential diagnosis

• Subacute stage
• recurrent pneumonia
• granulomatous lung diseases
• pneumoconiosis
• Wegeners granulomatosis

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HP Differential diagnosis

• Chronic stage
• IPF
• bronchiectasis
• COPD with pulmonary fibrosis
• MAC

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HP Management

• early diagnosis
• avoidance of further exposure
• protective devices - personal respirators
• relocation to a new job
• reducing microorganism contamination in the
  environment
• altering handling storage
• wetting compost
• using antibiotics to decrease fungal growth
• preventive maintenance on all A/C equipment

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HP key features
Immunopathology alveolitis, immune
complex granulomas, bronchiolitis lymphocytic
infiltration, fibrosis,air space destruction
Prognosis good good good
Time frame 4-48 hr weeks to 4 M. 4 M. to years
Acute Subacute Chronic
Clinical features fever, chills, cough hypoxemia,
aches dyspnea , cough, episodic flares dyspnea,
cough, fatigue, weight loss
HRCT ground glass infiltrates micronodules, air
trapping fibrosis, honey combing, emphysema

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Subacute HP, a 60-year-old dairy farmer had a
8-year history of intermittent dyspnea. CXR shows
bilateral reticulonodular interstitial
infiltration.
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Chronic pigeon breeders disease. This patient
has extensive pulmonary fibrosis cor pulmonale.
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Chronic HP, Pigeon breeders disease. Bilateral
reticulonodular densities are present.
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Acute HP, ground glass opacification
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HRCT of a patient with Chronic HP demonstrating
centrilobular nodules not associated with
bronchovascular bundles.
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Chronic HP, centrilobular nodules.
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Chronic HP, honeycombing in right upper lung
traction bronchiectasis
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Acute HP, mononuclear infiltration noncaseating
granulomas.
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Chronic HP, mostly lymphocytic cellular
infiltrate with epithelioid cells numerous and
clearly defined granuloma. (Wright-Giemsa)
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Giant cells are characteristic feature of HP.
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Chronic HP shows interstitial inflammation
associated with fibrosis.