A new post-mortem case study of UK patients who died from COVID-19 found signs of thrombosis in the major organs of all, with the lungs most affected, as well as a number of major unexpected findings.
Between 1 March 2020 and 30 April 2020, full post-mortem examinations were performed on nine patients with confirmed COVID-19 from London hospitals, including sampling of all major organs. A limited autopsy was done on one additional patient. The median age at death was 73 (interquartile range, 52-79) years.
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%]).
Diffuse alveolar damage was the most consistent lung finding (100%; 10); however, organisation was noted in patients with a longer clinical course.
The researchers documented lymphocyte depletion (particularly CD8-positive T cells) in haematological organs and haemophagocytosis. Evidence of acute tubular injury was noted in all nine patients examined.
Major unexpected findings were acute pancreatitis (two [22%] of nine patients), adrenal micro-infarction (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.
The series supports clinical data showing that the four dominant interrelated pathological processes in severe COVID-19 are diffuse alveolar damage, thrombosis, haemophagocytosis and immune cell depletion.
Additionally, the study reports several novel autopsy findings including pancreatitis, pericarditis, adrenal micro-infarction, secondary disseminated mucormycosis and brain microglial activation, which require additional investigation to understand their role in COVID-19.
The study, published in The Lancet Microbe, is the largest study to date of post-mortem examinations on COVID-19 patients in England.
