Clinical, radiologic, and morphological diagnosis of hypersensitivity pneumonitis

Aim. To study the relationship between clinical, radiologic, and morphological features in nonfibrotic and fibrotic hypersensitivity pneumonitis. Materials and methods. Clinical symptoms, data of high-resolution computed tomography, parameters of external respiration, and histological changes in the lung tissue obtained via open and transbronchial biopsies were studied retrospectively in 175 patients with hypersensitivity pneumonitis (HP). Statistical analysis was performed using the Statistica software. Results. We found that the clinical error rate in the diagnosis of HP was 84.5%, among pathologists - 92%. Among all the variants of HP, the most common was fibrotic HP. It was shown that non-necrotizing granulomas and giant cells in the cavities of the alveoli, microcells, and interalveolar septa were more typical of nonfibrotic HP. In fibrotic HP, peribronchial fibrosis, smooth muscle metaplasia in fibrotic areas, and the presence of fibroblastic foci in the walls of terminal bronchioles are signs of differential diagnosis with usual interstitial pneumonia. The classical triad of histological signs was observed in 19.2% of patients with nonfibrotic HP and in 5.6% of patients with fibrotic HP. Conclusion. Diagnosis of HP is complex and should be based on a multidisciplinary approach involving clinicians (pulmonologists), radiologists, functional diagnostics specialists, and pathologists. In this case, it is imperative to take into account and identify factors causing development of the disease, as well as the age of patients.