eosinophilic and hypersensitivity pneumonias wyatt e. rousseau, md
TRANSCRIPT
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) Solaymani-Dodaran M, West J, Smith C, Hubbard R. Extrinsic allergic alveolitis:
incidence and mortality in the general population. QJM 2007; 100: 233-237.
Case ReportBH, 50 y.o. WF NS, described three
episodes in three weeks of SOB, chest tightness, and hemoptysis. Initial episode lasted 2 hours, asso. with fever and chills, T. to 101F. , and tsp. of bloody phlegm.
PMH: hysterx 1984, on Premarin, Lexapro, Neurontin, trazadone, calcium, Fosamax. Parents both smoked, F d. lung CA, M d. emphysema and bronchiectasis, D with
asthma. Pt. had had severe complications of arthroscopy-6 surgeries, 3 ½ years of immobilization until TKR in 12/02, with
lymphedema, but had become quite physically fit with resting pulse usually 47. On PE,
macular, papular rash over abdomen, chest, and neck. No nodes, clear chest, and left leg
was not more swollen than right.
She had had chest CT 2/10/04 considered normal, and Lung scan 2/12/04 suggesting
airways disease with inhomogeneous perfusion and prolonged washout.
I recommended some lab work including D-dimer, CRP, and a venous doppler. She
declined; so I asked her to take a sputum cup to bring in if she coughed and I planned a
CTA if another episode. She called the next day after a worse episode of tightness, SOB,
and hemoptysis.
CTA 2/17/04 “tree in bud bilateral and diffuse” suggesting infection or
inflammation. Bronchoscopy 2/18/07 appeared normal, with biopsies revealing “mild chronic inflammation.” March 4
received report of outpatient sputum growing an AFB, and I assumed MAC, and discussed
Abx therapy. She then decided on VATS OLBx. (Bronch and OLBx cultures were
both negative ultimately.)
Lung biopsy revealed chronic bronchiolitis/hypersensitivity pneumonitis (extrinsic allergic alveolitis) with opinion from Mayo Clinic path
arriving on 3/30/04. “Hot tub lung due to MAC”. I recommended Prednisone 20 mg.
daily, but she had major psychiatric complications for which Seroquel was added and prednisone reduced. X-ray, spirometry, and symptoms resolved. Prednisone tapered
and stopped in late May. Recurrence of symptoms and rash in August/September.
HP -CT Findings
• Ground glass opacities
• Poorly defined centrilobular nodules
• Mosaic attenuation on inspiration
• Air trapping on expiration
• Reticulation (fibrosis) when chronic
Silva CI, Churg A, Muller NL. Hypersensitivity pneumonitis: spectrum of high-resolution CT and pathologic findings. Am J Roentgenol 2007; 188: 334-44.
Acute HP
• Clinical-Abrupt• Lab-ESR,IGG,RA,CRP,LDH, BAL
lymphocytosis, restrictive physiology• CXR-micronodular interstitial, but freq.
normal-HRCT needed, but not absolute• Histopathology-poorly formed,
noncaseating interstitial granulomas, monos, giant cells
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 in Textile Workers
• Byssinosis (brown lung) – cotton
• “Velvet” worker’s lung
• Upholstery fabric workers
• Lycoperdonosis (lycoperdon puffballs)
HP Prevention/Avoidance
• Reduction of antigen burden
• Design of facilities-moisture control
• Preventative maintenance, esp. HVAC
• Protective devices-filters, respirators