Hypersensitivity pneumonitis, acute

Category

Acute Poisoning

Acute/Chronic

Acute-Moderate (not life-threatening)

Synonyms

HP; Extrinsic allergic alveolitis; Farmer' lung; Bird-breeder's lung; Wood trimmer's disease; Maple bark-stripper's lung; Metalworking fluids HP

Biomedical References

Comments

Acute presentation: flu-like illness with cough;
Subacute: recurrent "pneumonia";
Chronic: exertional dyspnea, productive cough, and weight loss;
Most patients have abnormal imaging studies (chest x-ray or high-resolution CT). Crepitant rales are heard in some cases. Pulmonary function testing shows a restrictive defect in early disease and a restrictive, obstructive or mixed defect in late disease. Precipitating antibodies are neither sensitive nor specific, and their presence is no longer considered a hallmark of HP. Some patients have decreased diffusion capacity and arterial hypoxemia. If the diagnosis is in doubt, bronchoalveolar lavage (BAL) typically shows lymphocytosis. Surgical lung biopsy may be indicated if bronchoscopy is nondiagnostic. The disease latency varies from a few weeks to years after first exposure. Symptoms appear or worsen within a few hours of antigen exposure to bioaerosols of microbial or animal antigens or rarely to a few reactive chemicals. Complete recovery usually occurs if exposure is terminated early. Otherwise, the disease may progress to interstitial fibrosis. [Murray, p. 1783-1799]

Latency/Incubation

Weeks to years until "sensitized"; acute symptoms 4-12 hours after exposure;

Diagnostic

Clinical; Chest x-ray; HRCT; Pulmonary function testing; BAL; Lung biopsy;

ICD-9 Code

495.9

ICD-10 Code

J67.9

IDdx Link

Symptoms/Findings

Symptoms/Findings associated with this disease:

• cough
• dyspnea, acute
• fatigue
• fever
• headache
• inspiratory rales
• leukocytosis
• restrictive defect
• wheezing

Job Tasks

High risk job tasks associated with this disease:

• Generate flour dust
• Handle laboratory animals
• Inhale bioaerosols in the home, school, or office environment
• Inhale bioaerosols of moldy compost
• Inhale bioaerosols of moldy hay, silage, straw, or grain
• Inhale mists of microbially contaminated, water-based metalworking fluids
• Inhale moldy wood dust
• Produce nacre buttons from mollusc shells
• Produce silk (sericulture)
• Repeatedly debark maple trees to obtain sap
• Repeatedly inhale bioaerosols of bird droppings
• Repeatedly inhale bioaerosols of cheese containing Penicillum species
• Repeatedly inhale bioaerosols of moldy barley
• Repeatedly inhale bioaerosols of moldy sugarcane bagasse
• Repeatedly inhale bioaerosols of moldy wood pulp
• Repeatedly inhale bioaerosols of soy sauce fermentation starter
• Repeatedly inhale dust harvesting peat moss
• Repeatedly inhale dust of esparto grass
• Repeatedly inhale dust of moldy greenhouse soil
• Repeatedly inhale dust of moldy tobacco
• Repeatedly inhale moldy cork dust
• Spray epoxy or polyurethane paint, shellac, lacquer, or varnish
• Spray polyurethane foam insulation
• Use anhydride compounds to manufacture chemical products
• Use diisocyanates to manufacture polyurethane products
• Work in indoor pool as lifeguard or swimming instructor

Agents

Hazardous agents that cause the occupational disease:

• Fungi
• Hypersensitivity pneumonitis antigens