Pathologists find evidence of usual interstitial pneumonia in people with long COVID
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Usual interstitial pneumonia was a common finding in lung biopsies of people evaluated for post-COVID-19 interstitial lung disease, according to data published in EClinicalMedicine.
“We were seeing a lot of usual interstitial pneumonia, which isn’t the pattern we tend to associate with acute lung injury,” Kristine E. Konopka, MD, associate professor of thoracic pathology in the department of pathology and program director of the Pulmonary Pathology Fellowship at the University of Michigan, Ann Arbor, said in a university press release. “So, we think these are patients who had lung disease prior to COVID and maybe they just weren’t being followed by primary care physicians. They then have COVID, are still sick and their usual interstitial pneumonia is finally being picked up.”
Konopka and colleagues conducted a retrospective observational study to analyze surgical lung biopsies in the Michigan Medicine pathology database. The researchers evaluated surgical lung biopsies from 18 people with persistent ILD who were recovering from acute COVID-19 through April 2021. The median age was 56 years and 44% were women. Each case was independently reviewed by two thoracic pathologists who were masked to patient clinical data, radiographic findings, and original pathologic diagnoses and diagnoses made during consultation.
Nine cases had evidence of usual interstitial pneumonia. Two of those patients had superimposed acute lung injury. In addition, five cases showed a spectrum of acute lung injury, which ranged from persistent diffuse alveolar damage to organizing pneumonia. Four cases showed desquamative interstitial pneumonia, acute and organizing bronchopneumonia or no diagnostic abnormality, according to the results.
People with evidence of usual interstitial pneumonia on surgical lung biopsy were generally older (57 years vs. 53 years; P = .042) with preexisting lung disease prior to their COVID-19 infection (44% vs. 11%; P = .294) compared with those with no evidence of usual interstitial pneumonia.
Presurgical lung biopsy chest CT changes in people with evidence of usual interstitial pneumonia included ground glass with interstitial thickening (n = 5) and peripheral reticulations with bronchiectasis (n = 4), the researchers wrote. No case had ground-glass opacity only.
In people without evidence of usual interstitial pneumonia, the most common pathologic finding was ground-glass opacities, according to the researchers.
“Taken together with previous observations of histopathological findings in selected patients with persistent ILD following COVID-19, surgical lung biopsies in our cohort indicate that only a minority have persistent acute lung injury attributable to SARS-CoV-2 infection,” the researchers wrote. “Our preliminary study also suggests that many patients with persistent ILD have diffuse fibrotic lung disease that likely precedes SARS-CoV-2 infection.”