Usual interstitial pneumonia pattern: differential diagnosis and treatment possibilities

Abstract

The aim of this educational exhibit is to: •Describe the usual interstitial pneumonia pattern; •Review the main conditions with usual interstitial pneumonia pattern; •Discuss the differential diagnosis and treatment possibilities of those conditions. Background Fig. 1: Classification of ILDs (adapted from American Thoracic Society/European... Interstitial lung diseases (ILDs) are a heterogeneous group of nonneoplastic diffuse parenchymal lung diseases that result from damage to the lungs by varying combinations of inflammation and fibrosis. There are more than 300 conditions that are included in the total number of ILDs, which can be classified into four main groups (Fig. 1). Usual interstitial pneumonia is a characteristic pattern of idiopathic pulmonary fibrosis (IPF), which is the most frequent of the ILDs. However, UIP is not synonymous with IPF. UIP pattern can also be caused by variety of other causes including: •Connective tissue diseases (rheumatoid arthritis (RA), systemic sclerosis (SSC), idiopathic inflammatory myopathies, systemic lupus erythematosus, but is most commonly seen in RA); •Chronic hypersensitivity pneumonitis (CHP); •Drug toxicity; •Asbestosis. The most important among these are connective tissue disease-associated interstitial lung disease and CPH. Histologically confirmed UIP pattern of IPF is associated with significantly worse prognosis than other histological patterns of chronic interstitial pneumonia. Distinguishing UIP pattern causing conditions and making the the correct diagnosis is difficult and often requires integrated multidisciplinary approach involving pulmonologist, pathologist and radiologist, but it is essential for therapeutic options and prognosis, which vary in these groups. From radiological perspective, volumetric multidetector high resolution computed tomography (HRCT) is mandatory in patients with clinic and/or chest X-ray suspicion of ILD. . [...]