Hypersensitivity Pneumonitis

Hypersensitivity Pneumonitis

PRESENTED BY:SUKANYA HALDERM.TECH, BIOTECHNOLOGY

Hypersensitivity PneumonitisExtrinsic Allergic Alveolitis

A SYNDROME CHARACTERIZED BY DIFFUSE INFLAMMATION OF LUNG PARENCHYMA AND AIRWAYS IN RESPONSE TO INHALATION OF ANTIGENS TO WHICH THE PATIENT HAS BEEN PREVIOUSLY SENSITIZED

HP – Incidence and Mortality

General population based cohort study from a UK primary care database: 271 cases from 1991-2003, approx. 0.9 per 100,000 person years. Mean age at diagnosis 57; male=female

Increased risk of dying (hazard ratio 2.98)

Less likely to smoke (OR 0.56)

HP Findings

Ground glass opacities

Poorly defined centrilobular nodules

Mosaic attenuation on inspiration

Air trapping on expiration

Reticulation (fibrosis) when chronic

Classification of HP

Acute HP Subacute or Intermittent HP Chronic progressive HP

Subacute or Intermittent HP Clinical-gradual cough, dyspnea, fatigue,

anorexia, wt. loss, malaise; tachypnea and rales

Lab-BAL lymphocytosis, hypoxemia. Restrictive or mixed spiro, decreased DLCO

CXR-nml, micronodular, reticular. HRCT micronodules, ground glass, emphysema, fibrosis

Histopathology- noncaseating granulomas, bronchiolitis with or w/o organizing pneumonia

Chronic Progressive HP

Clinical-insidious cough, dyspnea, fatigue, weight loss, clubbing Lab-not very helpful-BAL lymphocytosis but not crisp; restrictive, but usually mixed. DL always reduced, and exertional hypoxemia CXR-may be normal, but usually progressive fibrosis; emphysema often Histopathology-granulomatous pneumonia, BO with or w/o OP, fibrosis

HP Diagnosis

Known exposure to antigen-History, environmental investigation, IgG antibodies

Compatible clinical, radiographic,and physiology

BAL lymphocytosis Positive inhalation challenge Histopathology

Clinical Prediction

Exposure to known antigen Positive precipitating antibodies to that antigen Recurrent symptoms Inspiratory crackles Sx occurring 4-8 hours after exposure Weight lossLacasse Y, for the HP Study Group. Clinical Diagnosis of

Hypersensitivity Pneumonitis. Am J Respir Crit Care Med 2003; 168: 952-958.

Helpful Clues to Recognize HP Hx recurring pneumonias, esp. if some

regularity Sx after moving to new house or job Pets, esp. birds, with patient or family Hx water damage to home or office Use of hot tub, sauna, or pool Others with similar sx or have left work for

illness Pt feels better when away from home or

office

HP Associated with Farming

Moldy hay, grain, silage-Farmer’s lung Mold on pressed sugar cane-Bagassosis Tobacco plants Mushroom workers Potato riddlers Cheese washers

HP Associated with Ventilation and Water-Related Contamination

Humidifier fever Unventilated shower Hot tub lung Sauna taker’s lung Lifeguard lung

HP Associated with Birds/Poultry

Bird fancier’s lung Poultry worker’s lung Turkey handling disease Canary fancier’s lung Duck fever

HP Associated with Veterinary Work and Animal Handling

Laboratory worker’s lung Pituitary snuff taker’s disease Furrier’s lung Bat lung Coptic lung (mummy handlers) Pearl oyster shell pneumonitis

HP Associated with Grain and Flour Processing

Grain measurer’s lung Miller’s lung Malt worker’s disease

HP Associated with Milling and Construction

Wood dust pneumonitis Sequoisis Maple bark disease Wood trimmer’s disease Suberosis (moldy cork) Composter’s lung Thatched-roof lung

HP Associated with Plastics, Painting, Electronics, Etc. Chemical HP – Toluene diisocyanate

Detergent worker’s lung Pauli’s reagent alveolitis Vineyard sprayer’s lung Bible printer’s lung Epoxy resin lung

HP Treatment

Antigen avoidance

Corticosteroids – 0.5-1 mg/kg daily

HP TreatmentHypersensitivity Pneumonitis may result in ILD.

Screening of ILD Patients may lead to finding traces of Hypersensitivity Pneumonitis.

Then we can treat those patients accordingly.

HP Prevention/Avoidance

Reduction of antigen burden Design of facilities-moisture control Preventative maintenance, esp. HVAC Protective devices-filters, respirators