Clinical features of interstitial lung diseases

Interstitial lung diseases (ILD) are heterogeneous groups of disorders that involve the interstitium of the lung. Lung biopsy is mandatory in most cases of ILD for diagnosis. In Korea, a few clinical data about ILD were analyzed on the basis of pathologic proof. Thus, we analysed the clinical profiles of patients with ILD who had lung biopsy in a tertiary university hospital.

Clinical and pathologic data concerning 100 patients who had open lung biopsy (OLB) and/or transbronchial lung biopsy (TBLB) were prospectively analysed. Two patients were excluded because one patient was proven to have metastatic cancer and the other to have miliary tuberculosis. One patient had two combined diseases: rheumatoid arthritis and pneumoconiosis. Thus, 99 cases were analysed from 98 patients. Demographic characteristics, pulmonary functions and pathologic findings were analysed according to the disease entities of ILD. Pathologic findings were classified only in patients who had OLB. Clinical courses were also analysed during follow-up.

OLB was performed on 68 cases with concomittant TBLB in 18 cases and 30 cases had TBLB only. Mediastinal lymph node biopsy has performed on one case. The most common cause of ILD was IPF (51.5%), which was followed by CVD.PF (15.2%) and HP (9.1%). Average age of 51 cases with idiopathic pulmonary fibrosis (IPF) was 60 +/- 11 years, that of 15 cases with collagen vascular disease associated pulmonary fibrosis (CVD-PF) was 46 +/- 17 years and that of 9 cases with hypersensitivity pneumonitis (HP) was 53 +/- 8.1 years. In IPF, CVD-PF AND HP, male to female ratio was equal. But female was dominant in sarcoidosis and male was dominant in pneumoconiosis. Pulmonary function tests (PFT) in IPF, CVD-PF and HP were restrictive patterns in half of the cases. In pneumoconiosis and sarcoidosis, PFT showed normal pattern. Usual interstitial pneumonia (UIP) was the most common pathologic type in IPF and CVD-PF. The most common cause of CVD-PF was rheumatoid arthritis. The overall mortality rate was 12.1%.

We reported that the ILD had a variety of disease entities and pathologic types even in one tertiary referral hospital. We hope that a multi-center study will be performed on the basis of pathologic proof in the future.