These findings hint at the role of pre-existing conditions in raising the risk of an individual having a severe case of COVID-19 once infected
At the University of Michigan, a team of pathologists have been researching the factors that might cause some patients infected by SARS-CoV-2 to suffer persistent respiratory problems, often described as “long COVID.” They have identified factors that place some individuals at higher risk for these problems.
Little is known about how the SARS-CoV-2 coronavirus affects the body long-term. Millions of people who have survived COVID-19 infections are living with chronic symptoms, including persistent respiratory problems such as shortness of breath. However, until now, it was not clear what may be causing these symptoms in some people but not others, even after the coronavirus has completely cleared their bodies.
Now, anatomic pathologists at Michigan Medicine, formerly the University of Michigan Health, believe they may have discovered what is causing ongoing respiratory problems in some patients who have recovered from the COVID-19 infection—pre-existing conditions.
The researchers examined lung biopsies from COVID-19 patients who continued to experience lingering symptoms. They discovered in some individuals lung damage that was present prior to contracting the virus.
“Some of the early publications and popular press around long COVID has implied or assumed that once you had COVID, everything that happens next is COVID-related,” said anatomic pathologist and senior author of the study Jeffrey Myers, MD (above), Vice Chair for Clinical Affairs and Quality at Michigan Medicine, in a news release. “Of course, that might or might not be true,” he added. (Photo copyright: University of Michigan.)
The research team analyzed lung biopsies from 18 COVID-19 survivors who were still experiencing respiratory symptoms or had abnormal computed tomography (CT) scans after the virus was no longer present in their bodies. The researchers found ground glass opacities on the radiological scans of 14 of those patients.
According to the news release, this finding indicates there were “areas of the lungs that appear as a cloudy gray color as opposed to the dark color of normal air-filled lungs, on a chest X-ray or CT scan.”
The biopsies exhibited evidence of pre-existing lung scarring and proof of diffuse alveolar damage, which is typically seen in patients with acute respiratory illnesses. Only five of the patients examined in the study were known to have lung disease prior to their COVID-19 diagnoses.
The researchers found that the most common condition present in these 18 patients was usual interstitial pneumonia (UIP). This condition, also known clinically as idiopathic pulmonary fibrosis (IPF), is a common form of pulmonary fibrosis that is characterized by progressive scarring and stiffening of both lungs.
“We were seeing a lot of UIP, which isn’t the pattern we tend to associate with acute lung injury,” said Kristine Konopka, MD, Clinical Associate Professor at Michigan Medicine and lead author of the study, in the news 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 had COVID, are still sick, and their UIP is finally being picked up.”
Could Patients Have Lung Disease and Not Know it?
“The notion,” Myers noted in the news release, “that a person could have chronic lung damage and not know it was unheard of until relatively recently.” He also explained that UIP/IPF is a progressive disease that gets worse with time and that an infection like COVID-19 can accelerate the illness to a more serious condition known as an acute exacerbation of IPF, which can lead to death.
“SARS-CoV-2 comes along and does to the lung, from a pathology perspective, exactly what happens with an acute exacerbation,” Myers said.
The researchers also stated that it’s impossible to determine for certain whether the SARS-CoV-2 virus caused the UIP/IPF without the existence of full clinical histories of the patients prior to their COVID-19 diagnoses. They hope their research will motivate clinicians to be cautious before automatically attributing respiratory symptoms to long COVID in survivors of the virus. It is possible that the lung damage was present prior to the coronavirus.
“You shouldn’t make assumptions but [instead] ask the right questions, the first of which would be ‘I wonder if this is really COVID?’ What you do after that depends on the answer to that question,” he added.
The Michigan Medicine researchers published their findings in the journal eClinicalMedicine, titled, “Usual Interstitial Pneumonia Is the Most Common Finding in Surgical Lung Biopsies from Patients with Persistent Interstitial Lung Disease Following Infection with SARS-CoV-2.”
This research is an example of how pathologists can add insight and value into the deeper understanding of the processes involved in specific diseases. Dark Daily invites any of our readers who are aware of other pathologist-authored studies or published papers about COVID-19 to alert us to the availability of those works.
—JP Schlingman
Related Information:
Pathologists Find Evidence of Pre-existing Chronic Lung Disease in People with Long COVID
