Small airway disease persists in long COVID patients

DCT imaging of patients with acute sequelae of COVID-19 (PASC) (more commonly known as long COVID) revealed that small airway disease persists for several months after infection.

According to Alejandro Comellas, chest CT scans of about 100 long COVID patients (one-third of those hospitalized after the initial infection) showed air entrapment in 58% and ground glass in 51% of the patient’s lungs. The turbidity was seen. , MD, University of Iowa, Iowa City, and colleagues.

“”[Ground glass opacities]Frequently observed during acute COVID-19, often with an organized pneumonia pattern, “is significantly more common in severely ill patients and affects 94% of patients admitted to the intensive care unit (ICU). It affected and affected 36% of patients.A person who did not require hospitalization (walking group), Comellas and his colleagues wrote: Radiology..

“For the first time, we describe small airway disease in this population of persistent COVID-19 patients,” Comellas said in a press release. “Something is happening in the distal airways associated with either inflammation or fibrosis, which gives us a signal of air trapping.”

CT scans were performed at a median 75 days after the patient’s initial diagnosis, and about half of the air trapping participants also had ground glass opacity. This is the latest in the increase in conditions associated with long COVIDs.Other than that “Forgetfulness” Dyspnea and abdominal pain..

Most notably, Comellas et al. Found that the average percentage of all lungs classified as ground glass shadows was 28.7% in the ICU group and 13.2% in patients admitted without ICU care (inpatient group). Both were found to be significantly higher than 3.7%. The walking group was significantly higher than the healthy controls (0.06%, PBoth are <0.001).

Lung capacity measurements and lung volume in walkable participants were not different compared to healthy controls, but in these mild cases the proportion of lungs affected by opacity of the glass was “ongoing”. It suggests lung inflammation, edema, or fibrosis, the team wrote.

The average percentage of all lungs affected by air trapping was 27.3% in the ICU group, 34.6% in the inpatient group, 25.4% in the walking group, and 7.2% in the healthy control group.

“No airflow obstruction was observed by spirometry in any of the groups, suggesting that air confinement in our cohort was due to the involvement of small airways rather than large airways.” Comellas et al. Wrote. “Small airways are not easily identifiable in lung images, Many studies We have established the presence of air trapping on chest CT as a marker for functional small airway disease (fSAD). “

“In summary, our findings suggest that SARS-CoV-2 infection itself leads to fSAD and air trapping,” the researchers write.

Write in Ancillary editorialBrett Elicker, MD of the University of California, San Francisco, said: “Given the long-term effects of COVID-19 infection on the lungs, this is an important finding and may correspond to the development of obstructive bronchiolitis after viral stenosis. Other viral infections. , Especially found in adenovirus infections. “

Comellas and co-authors suggested that a potential mechanism may be associated with the ACE2 receptor. The ACE2 receptor is expressed throughout the lungs and in the small respiratory tract.

In addition, the study found that the median bronchodilator vital capacity (FVC) and forced expiratory volume per second (FEV1) in the inpatient group were significantly lower than in the walking group, but between the walking groups. No difference was seen in. Healthy control.

Both Elicker and the authors of the study stated that it is not clear whether these abnormalities in the airways of patients with long COVID are permanent and that longer-term studies are needed.

A single-center study was conducted in Iowa from June to December 2020 and included 100 patients who were symptomatic more than 30 days after COVID-19 infection. 106 healthy controls were included from another study conducted in 2018.

In the PASC group, 67 received outpatient treatment during the acute infection period (21 days after diagnosis), 17 were hospitalized without ICU treatment, and 16 were hospitalized with ICU treatment.

The median age in this group was 48 years, but those admitted with or without ICU were older than those who only needed outpatient treatment (60, 64, 44, respectively). Overall, 66% were women, 85% were white, 10% were Latino American, and 5% were black.

A total of 76 people were co-existing: 59 were obese, 27 were hypertensive, and 26 were asthma. In the hospitalized group, 53% were smokers, but three-quarters were not smokers.

Comellas et al. Stated that the limits of this study did not represent recent variants such as Delta and Omicron, as the limits of this study included only those who were infected early in the pandemic.