Autopsy Confirms Severe Alveolar Damage in COVID-19

Jennifer Garcia

May 27, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Postmortem findings confirm that coronavirus disease 2019 (COVID-19) causes significant alveolar damage, but thrombotic disease may play a role in mortality as well.

In a research letter published online May 21 in JAMA, researchers report postmortem data from 10 consecutive patients with confirmed COVID-19 noting that "acute and organizing diffuse alveolar damage" was the primary histopathologic finding and the leading cause of death among patients, regardless of treatment with invasive ventilation.

"These findings correlate very well with the leading symptoms in COVID-19 such as cough, fever, as well as respiratory distress and respiratory failure in patients with a severe disease course," lead author Rainer Claus, MD, from University Medical Center, Augsburg, Germany, told Medscape Medical News.

He notes, however, that it is "too early to conclude from these changes on specific therapeutic consequences."

Histopathology of the respiratory tract included changes ranging from hyaline membrane formation and thickened alveolar septa with perivascular lymphocyte-plasmocytic infiltration to pronounced fibroblastic proliferation, partial fibrosis, and pneumocyte hyperplasia leading to interstitial thickening.

In a separate, unrelated report published online May 6 in the Annals of Internal Medicine, researchers evaluated postmortem data from 12 consecutive confirmed COVID-19 patients and found similar diffuse alveolar damage in the majority (8/12) of patients; however, seven of the 12 patients also had evidence of deep venous thrombosis, and in four of those patients, pulmonary embolism was considered the direct cause of death.

Of note, no thromboembolic events were noted in the case series reported by Claus and colleagues. When asked why this may be the case, Claus explained that a few caveats must be considered, primarily that analysis of the deep veins of the legs to look for peripheral thrombosis was not performed in their series. Claus also noted that "mortality differs strikingly from region to region, indicating that the disease course might differ due to unknown reasons."

Patients in both reports were predominately male, older than 70 years, and had pre-existing medical conditions. Both reports also noted mild inflammatory changes in other organs including the liver, kidneys, and heart; however, the clinical relevance of these findings is not clear.

The authors of both reports acknowledge the findings may not be generalizable to a broader population as the sample sizes are small, but they encourage clinicians treating patients with COVID-19 to consider performing more postmortem evaluations in an effort to learn more about disease pathology and possible treatment opportunities.

"Several reports about autopsy in COVID-19 patients have revealed significant histopathological and clinically relevant disease characteristics," said Claus.

"It is obvious that postmortem examinations generate important insights into the disease manifestations and the mechanisms of organ failure," and these evaluations "are the only opportunity to macroscopically observe organs and subsequently take ideal samples for histopathological and molecular analyses and generate profound knowledge about this disease," he concluded.

The authors of the JAMA article have disclosed no relevant financial relationships. The authors of the study published in Annals of Internal Medicine have reported financial relationships with a variety of companies; a complete list is available on the journal's website.

Ann Int Med. Published online May 6, 2020. Full text

JAMA. Published online May 21, 2020. Full text

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