3. 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)
4. HP Findings
Ground glass opacities
Poorly defined centrilobular nodules
Mosaic attenuation on inspiration
Air trapping on expiration
Reticulation (fibrosis) when chronic
7. 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
8. 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
9. HP Diagnosis
Known exposure to antigen-History,
environmental investigation, IgG antibodies
Compatible clinical, radiographic,and physiology
BAL lymphocytosis
Positive inhalation challenge
Histopathology
10. Clinical Prediction
Exposure to known antigen
Positive precipitating antibodies to that antigen
Recurrent symptoms
Inspiratory crackles
Sx occurring 4-8 hours after exposure
Weight loss
Lacasse Y, for the HP Study Group. Clinical Diagnosis of
Hypersensitivity Pneumonitis. Am J Respir Crit Care Med 2003; 168:
952-958.
11. 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
12. 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
13. HP Associated with
Ventilation and Water-
Related Contamination
Humidifier fever
Unventilated shower
Hot tub lung
Sauna taker’s lung
Lifeguard lung
20. HP Treatment
Hypersensitivity Pneumonitis may result in ILD.
Screening of ILD Patients may lead to finding traces of Hypersensitivity Pneumonitis.
Then we can treat those patients accordingly.
21. HP Prevention/Avoidance
Reduction of antigen burden
Design of facilities-moisture control
Preventative maintenance, esp. HVAC
Protective devices-filters, respirators