Incidental discovery of interstitial lung disease: diagnostic approach, surveillance and perspectives

Abstract

The incidental discovery of pre-clinical interstitial lung disease (ILD) has led to the designation of interstitial lung abnormalities (ILA), a radiological entity defined as the incidental finding of computed tomography (CT) abnormalities affecting more than 5% of any lung zone. Two recent documents have redefined the borders of this entity and made the recommendation to monitor patients with ILA at risk of progression. In this narrative review, we will focus on some of the limits of the current approach, underlying the potential for progression to full-blown ILD of some patients with ILA and the numerous links between subpleural fibrotic ILA and idiopathic pulmonary fibrosis (IPF). Considering the large prevalence of ILA in the general population (7%), restricting monitoring only to cases considered at risk of progression appears a reasonable approach. However, this suggestion should not prevent pulmonary physicians from pursuing an early diagnosis of ILD and timely treatment where appropriate. In cases of suspected ILD, whether found incidentally or not, the pulmonary physician is still required to make a correct ILD diagnosis according to current guidelines, and eventually treat the patient accordingly.

Do not dismiss interstitial lung abnormalities

“…Patients with ILAs should be evaluated within 3 to 12 months of diagnosis. 10 A clinical assessment is done to assess for symptoms and to identify exposures. PFTs are performed to detect physiologic impairment.…”

“…Risk factors for ILAs have been identified. 10 Non-modifiable risk factors include older age, male gender and genetic predisposition (MUC5B promoter variant rs35705950). Modifiable risk factors include tobacco smoke and other inhalational exposures.…”

Possibilities of non-invasive diagnosis of fibrotic phenotype of interstitial lung diseases

“…В качестве возможных биологических маркеров с разной степенью доказательности предложены сывороточные маркеры (KL-6, сурфактантные протеины, матриксные металлопротеиназы, хемокины, микроРНК и др. ), количество моноцитов периферической крови, длина теломер, физиологические индексы (gender, age and physiology index -GAP), КТ-предикторы и многие другие [15][16][17][18][19][20]. Однако в настоящее время ни один из приведенных показателей не может считаться в должной степени чувствительным и специфичным.…”

Association of MUC5B promoter polymorphism with interstitial lung changes after COVID-19: A preliminary observation

“…Further investigation is required into the downstream effects of this polymorphism in the lung tissue of individuals with COVID-19 both in the acute as well as post-acute phases. Longer follow up is required to reveal whether such PCICs progress to ILD over months to years as happens with ILAs in a proportion of the affected individuals 9 . Furthermore, it can be hypothesized that ILAs in the general population that are detected incidentally might result from undiagnosed viral illnesses.…”