August 20, 2020
Small Postmortem Study of COVID-19 Patients in United Kingdom Describes Histopathological Findings and Viral Tropism
August 20, 2020—Brian Hanley, MBBCh, et al conducted a postmortem study that aimed to describe the histopathological findings and viral tropism in a case series of 10 patients with severe fatal COVID-19 in the United Kingdom. The study is available online in The Lancet: Microbe.
The investigators’ interpretation of the findings in The Lancet: Microbe abstract stated, “Our series supports clinical data showing that the four dominant interrelated pathological processes in severe COVID-19 are diffuse alveolar damage, thrombosis, hemophagocytosis, and immune cell depletion. Additionally, we report here several novel autopsy findings including pancreatitis, pericarditis, adrenal microinfarction, secondary disseminated mucormycosis, and brain microglial activation, which require additional investigation to understand their role in COVID-19.”
Patient eligibility criteria for the study included age > 18 years, premortem diagnosis of SARS-CoV-2 infection, and COVID-19 listed clinically as the direct cause of death.
As summarized in The Lancet: Microbe, full postmortem examinations were conducted on nine patients with confirmed COVID-19, including sampling of all major organs, between March 1 and April 30, 2020. A limited autopsy was done on one additional patient.
The investigators conducted histochemical and immunohistochemical analyses. Histopathological findings were reported by subspecialist pathologists. Viral quantitative reverse transcription polymerase chain reaction analysis was done on tissue samples from a subset of patients.
The median age at death in the 10-patient study cohort was 73 years (interquartile range, 52-79).
The investigators reported that thrombotic features were observed in at least one major organ in all full autopsies, predominantly in the lung (eight [89%] of nine patients), heart (five [56%]), and kidney (four [44%]). The most consistent lung finding (in all 10 patients) was diffuse alveolar damage; however, organization was noted in patients with a longer clinical course.
The investigators documented lymphocyte depletion (particularly CD8-positive T cells) in hematological organs and hemophagocytosis. Evidence of acute tubular injury was noted in all nine patients examined.
According to the investigators, major unexpected findings were acute pancreatitis (two [22%] of nine patients), adrenal microinfarction (three [33%]), pericarditis (two [22%]), disseminated mucormycosis (one [10%] of ten patients), aortic dissection (one [11%] of nine patients), and marantic endocarditis (one [11%]). Viral genomes were detected outside of the respiratory tract in four of five patients.
The presence of subgenomic viral RNA transcripts provided evidence of active viral replication outside the respiratory tract in three of five patients, reported the investigators in The Lancet: Microbe.