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Hypersensitivity pneumonitis: a noninfectious granulomatosis
1University of Southern California School of Medicine, Los Angeles 90033, USA.
Seminars in Respiratory Infections
|June 1, 1995
Summary
Hypersensitivity pneumonitis is an immune lung disease from inhaling organic antigens. Diagnosis involves exposure history, antibodies, and lung biopsy, with antigen avoidance as primary treatment.
Area of Science:
- Immunology
- Pulmonology
- Pathology
Background:
- Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is an immune-mediated lung condition.
- It results from repeated inhalation of organic antigens, leading to inflammation and potential fibrosis.
- HP is unique in its lung-specific granulomatous inflammation.
Purpose of the Study:
- To describe the immunological basis, histological features, and clinical presentation of hypersensitivity pneumonitis.
- To outline diagnostic approaches and confirmative tests for HP.
- To discuss therapeutic strategies and prognosis for patients with HP.
Main Methods:
- Review of histological findings including mononuclear cell infiltration and granulomas.
- Analysis of clinical symptoms such as fever, cough, and dyspnea.
- Diagnostic criteria based on environmental exposure, serum antibodies (IgG), bronchoalveolar lavage (BAL) findings (suppressor cytotoxic lymphocytosis), and lung biopsy (granulomatous alveolitis).
Main Results:
- The primary lesion involves diffuse mononuclear cell infiltration progressing to granulomas and potentially fibrosis.
- Acute HP symptoms can mimic other pneumonitis forms.
- Diagnosis is supported by a history of exposure, specific antibodies, BAL cytology, and lung biopsy findings.
Conclusions:
- Antigen avoidance is the cornerstone of HP management.
- Corticosteroids are used to manage inflammation.
- Untreated or advanced HP can lead to respiratory failure, cor pulmonale, and death.