[Target organ the lungs: diversity of fibrotic pulmonary diseases]

Fibrotic lung diseases are part of the large and heterogeneous group of interstitial lung diseases (ILD), which are characterized by a progressive fibrotic remodelling of alveolar lung parenchyma.

Overview of the spectrum of fibrotic lung diseases.

A literature search was carried out in the PubMed and MEDLINE database.

The etiology of fibrotic ILD is diverse and includes inhaled exogenous noxious substances (dust, gases), infections, drug reactions, ionizing radiation and endogenous autoimmune or rare genetically determined metabolic and storage disorders; however, the etiology of some ILDs, so-called idiopathic interstitial pneumonia (IIP), is not fully understood although environmental pollution, tobacco smoke and genetic polymorphisms have been identified as risk factors. The most important and best studied representative of IIP is idiopathic pulmonary fibrosis (IPF). The diagnosis of ILD is complex and requires an interdisciplinary approach taking the clinical presentation, radiological patterns, and possibly bronchoalveolar lavage and histological findings into account. Characteristic of progressive fibrotic lung disease is progressive fibrotic tissue remodeling, which is manifested as clinical, functional and radiological deterioration and is referred to as progressive pulmonary fibrosis (PPF). Antifibrotic drugs delay the progression of IPF and PPF but are not curative.

In addition to early diagnosis and preventive strategies, a better understanding of the causes of fibrotic ILD is required in order to avoid triggering noxious agents, identify dysregulated signalling pathways and develop targeted treatment.