SARS-CoV-2-related lung pathology: macroscopic and histologic features and their clinical implications

Multi-organ dysfunction and outcomes in pregnancy associated COVID-19 infection - descriptive review of pathological findings

OBJECTIVE(S)

Comparative clinical and morphological characterization of lesions of the vascular and nervous system in cases of maternal death associated with COVID-19.

STUDY DESIGN

The study included autopsy in 12 cases of maternal death with a positive intravital result for SARS-CoV-2 by reverse transcription polymerase chain reaction. For histopathology, tissue samples were taken from the internal organs of each patient. Pieces of organs were fixed and stained according to the standard protocol. The relative number of microvessels with vasculitis and fibers of the peripheral nervous system with infiltration by immune cells was studied. All morphological changes were classified depending on the severity of the damage.

RESULTS

The average age of patients with a fatal outcome was 35 ± 4.4 years. Time to death after onset of symptoms averaged 16 ± 4.4 days. Dystrophic lesions (necrosis and apoptosis) of the villous and extravillous trophoblast and decidual tissue were observed in the studied placentas. Histopathological signs of mild and severe lesions of the peripheral nervous system in the organs of the gastrointestinal tract were detected in 2 (16.7%) and 10 (83.3%) cases, respectively, in the myocardium in 4 (33.3%) and 8 (66.7%) cases. Histopathological signs of severe damage to the microvascular bed in the organs of the gastrointestinal tract were registered in 9 (75%) cases.

CONCLUSION(S)

The main clinical feature of this cohort was that death occurred in a long-term period, in most cases with a negative PCR. The histopathological pattern was a non-acute injury with an immune component of the microvascular bed and the autonomic nervous system with predominant damage to the myocardium and intestines.

WHAT DOES THIS STUDY ADD TO THE CLINICAL WORK

This study makes it possible to even better study the immunopathological profile in organs and tissues in pregnant women with a fatal outcome when affected by a viral infection, in particular Covid-19. This knowledge can be used when humanity encounters other viral pandemics in the future.

Cause of death based on systematic post-mortem studies in patients with positive SARS-CoV-2 tissue PCR during the COVID-19 pandemic

IMPORTANCE

Assessment of the causative association between the COVID-19 and cause of death has been hampered by limited availability of systematically performed autopsies. We aimed to present autopsy-confirmed causes of death in patients who died with COVID-19 and to assess the association between thrombosis and diffuse alveolar damage consistent with COVID-19 (DAD).

METHODS

Consecutive forensic (n = 60) and clinical (n = 42) autopsies with positive post-mortem SARS-CoV-2 PCR in lungs (age 73 ± 14 years, 50% men) were included. The cause of death analysis was based on a review of medical records and histological reports. Thrombotic phenomena in lungs were defined as pulmonary thromboembolism (PE), thrombosis in pulmonary artery branches or microangiopathy in capillary vessels.

RESULTS

COVID-19 caused or contributed to death in 71% of clinical and 83% of forensic autopsies, in whom significant DAD was observed. Of the patients with COVID-19 as the primary cause of death, only 19% had no thrombotic phenomena in the lungs, as opposed to 38% amongst those with COVID-19 as a contributing cause of death and 54% amongst patients whose death was not related to COVID-19 (p = 0.002). PE was observed in 5 patients. Two patients fulfilled the criteria for lymphocyte myocarditis.

CONCLUSIONS

Vast majority of all PCR-positive fatalities, including out-of-hospital deaths, during the SARS-CoV-2 pandemic were related to DAD caused by COVID-19. Pulmonary artery thrombosis and microangiopathy in pulmonary tissue were common and associated with the presence of DAD, whilst venous PE was rarely observed. Histology-confirmed lymphocyte myocarditis was a rare finding.

Pathological diagnosis of Coronavirus-related nephropathy: insight from postmortem studies

A novel coronavirus pneumonia first occurred in Wuhan, China in early December 2019; the causative agent was identified and named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the World Health Organization (WHO), and the resulting disease termed coronavirus disease 2019 (COVID-19), according to the WHO coronavirus disease situation reports. This condition has spread rapidly all over the world and caused more than 125 million cases globally, with more than 2 million related deaths. Two previous outbreaks due to zoonotic coronaviruses have occurred in the last 20 years, namely the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), causing high morbidity and mortality in human populations upon crossing the species barriers. SARS-CoV-2, SARS-CoV, and MERS-CoV show several similarities in pathogenicity and clinical presentations, the latter ranging from asymptomatic infection to severe acute respiratory distress syndrome (ARDS) and multiorgan impairment. Acute kidney injury (AKI) has been commonly reported in patients with CoV infections; therefore, pathological analysis of renal parenchyma in these patients has been carried out in order to improve knowledge about underlying mechanisms. Viral infection has been demonstrated in the renal tubular epithelial cells by electron microscopy (EM), immunohistochemistry (IHC), and in situ hybridization (ISH), although with conflicting results. Light microscopy (LM) changes have been described in the renal parenchyma primarily in the form of acute renal tubular damage, possibly due to direct viral cytopathic effect and immune-mediated mechanisms such as cytokine storm syndrome. In this review, we describe and discuss the spectrum of histological, ultrastructural, and molecular findings in SARS-CoV, MERS-CoV, and SARS-CoV-2-related renal pathology obtained from postmortem studies, as well as intrinsic limitations and pitfalls of current diagnostic techniques.