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Review
. 2024 Apr 18:11:1296890.
doi: 10.3389/fmed.2024.1296890. eCollection 2024.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Malik A Althobiani  1   2 , Anne-Marie Russell  3   4 , Joseph Jacob  5   6 , Yatharth Ranjan  7 , Amos A Folarin  7   8   9   10 , John R Hurst  1 , Joanna C Porter  5
Affiliations
Review

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Malik A Althobiani et al. Front Med (Lausanne). .

Abstract

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.

Keywords: hypersensitivity pneumonitis; idiopathic pulmonary fibrosis; interstitial lung disease; nonspecific interstitial pneumonia; sarcoidosis.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Illustrates normal lungs and lungs with a type of ILD (idiopathic pulmonary fibrosis) (1).
Figure 2
Figure 2
Classification of ILDs adapted from ATS/ERS 2013 guidelines and Wijsenbeek et al. (9).
Figure 3
Figure 3
Diagnostic algorithm adapted from Wijsenbeek et al. (9).
Figure 4
Figure 4
Common functional abnormalities in patients with ILD. VC, vital capacity; FRC, functional residual capacity; ITGV, intrathoracic gas volume; TLC, total lung capacity; R5Hz, resistance measured at 5 Hertz; DLCO, diffusion capacity; PaO2, partial pressure for oxygen; SaO2, arterial saturation of oxygen; A-a O2 gradient, alveolar-arterial oxygen gradient; VO2, oxygen uptake.
Figure 5
Figure 5
A visual representation of patterns of damage that could be seen on a CT scan in several common interstitial lung diseases. The lower section of the figure represents organizing pneumonia, where a CT may show consolidaiton, a perilobular pattern and nodules. The second section shows Sarcoidosis, where a CT often shows bilateral symmetrical hilar lymph nodal enlargment, fibrosis in the posterior segments of the upper lobes and perilymphatic nodules. The middle section represents hypersensitivity pneumonitis, where focal ground-glass opacity, air trapping, increased attenuation lung in the lung forming the three-density sign can be seen with or without reticulation, traction bronchiectasis and honeycomb cysts. The section second from top illustrates nonspecific interstitial pneumonia, whilst the top section shows a usual interstitial pneumonia pattern which if basal and lower zone predominant in the absence of an identifiable cause of disease could be diagnosed by a multidisciplinary team as idiopathic pulmonary fibrosis.
Figure 6
Figure 6
Management algorithm adapted from Wijsenbeek et al. (9).
See this image and copyright information in PMC

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