Specialized CT protocol reveals small airways disease in COVID long haulers
Regardless of the degree of infection severity, COVID can cause potentially long-lasting small airways disease, experts recently shared in Radiology.
Up to 50% of COVID survivors are considered “COVID long haulers” and close to 30% of these individuals continue to suffer from lingering coughs and dyspnea months after recovering from the infection, despite having endured more mild cases.
“Survivors of severe COVID-19 have pulmonary function abnormalities that persist for weeks to months after resolution of the acute illness,” senior author on the study Alejandro P. Comellas, MD, professor of internal medicine in the division of pulmonary and critical care medicine at the Carver College of Medicine, University of Iowa, and co-authors explained. “The long-term effects of SARS-CoV-2 infection in these patients are poorly understood, but the potential impact on our healthcare systems is enormous given the millions of infections worldwide, most of whom had mild disease.”
The researchers enrolled 100 patients who suffered from respiratory symptoms that persisted for more than 30 days after their COVID diagnosis and compared them to a control group of 106 healthy individuals. A chest CT protocol that included both inspiration and expiration imaging was completed for all COVID patients (median 75 days after diagnosis) to check for regional air trapping. Based on the highest level of care they required during their infection, the long haulers were classified as ambulatory (67), hospitalized (17) or requiring the intensive care unit (16).
Air trapping was observed consistently on expiratory imaging throughout each COVID cohort, with those hospitalized exhibiting the findings most often at 34.6%, compared to 25.4% and 27.3% in the ambulatory and ICU groups. These findings remained prevalent for 8 out of 9 individuals who had follow up imaging up to 200 days after their initial diagnosis.
The researchers noted that the obstruction of airflow was not observed on spirometry for any participants, which led them to suggest that the air trapping visualized on CT images was the result of pathology in the small rather than large airways.
“Our findings suggest that SARS-CoV-2 infection itself leads to functional small airways disease and air trapping,” the doctors said. “Something is going on in the distal airways related to either inflammation or fibrosis that is giving us a signal of air trapping.”
The authors said that they intend to continue monitoring those enrolled in their research to determine whether their symptoms improve or turn into progressive lung disease.
“If a portion of patients continues to have small airways disease, then we need to think about the mechanisms behind it,” they said.
The detailed research can be viewed in Radiology.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.