Hypersensitivity pneumonitis

Definition

Hypersensitivity pneumonitis is an inflammatory syndrome affecting the alveoli of the lungs due to repeated inhalation of various environmental antigens. It involves immune-mediated lung inflammation and can lead to chronic lung disease if untreated.

5 Must Know Facts For Your Next Test

1. Hypersensitivity pneumonitis is triggered by inhalation of organic dusts, molds, or chemicals.
2. It involves both Type III and Type IV hypersensitivity reactions.
3. Symptoms include cough, fever, chills, and dyspnea (shortness of breath).
4. Diagnosis often requires a combination of patient history, imaging studies like high-resolution CT scans, and sometimes lung biopsies.
5. Long-term exposure without treatment can result in pulmonary fibrosis.

Related terms

Type III Hypersensitivity: Immune complex-mediated reaction resulting in tissue damage.

Type IV Hypersensitivity: Delayed-type reaction mediated by T-cells causing cell-mediated immune responses.

Pulmonary Fibrosis:

Progressive lung disease that results from scarring and thickening of the lung tissue.