Pathological Lung Patterns of COVID-19 and its Clinical Correlation to Disease Severity

Coronavirus disease-2019 (COVID-19) infection can result in pulmonary complications ranging from mild illness to severe life-threatening disease. There are limited studies correlating the association between the clinical course of COVID-19 and histopathological findings. This study aimed to examine the postmortem histopathological changes in lung tissue of COVID-19-positive patients and to correlate those changes with disease severity.

This prospective observational study was conducted in adult COVID-19-positive patients. Postmortem core needle biopsy (CNB) of the lung was done using ultrasonography guidance within 1 hour of death. Histopathological analyses were performed by two expert pulmonary pathologists. The demographic and clinical data of the patients were recorded to correlate them with histopathological findings.

In total, 48 patients were assessed for inclusion, and 21 patient relatives consented for the study. The median duration of illness was 21 (range 9-38) days, the predominant histopathological finding was diffuse alveolar damage (DAD) in most patients (19/21), followed by pneumonia (13/21). Exudative, intermediate, and advanced DAD patterns were seen in 9.5%, 52.4%, and 28.6% of cases, respectively. Advanced DAD was associated with a longer duration of disease. The pneumonia findings were associated with positive respiratory and blood cultures. The microvascular thrombus was seen only in one patient.

The predominant pathological findings in our patients were DAD and pneumonia. The DAD type correlated with the duration of illness, and we attributed pneumonia findings to secondary infection. The incidence of microvascular thrombi was low, and it might reflect the effect of treatment with anticoagulation.

Maddani SS, Rao R, Deepa HC, Noronha AK, Chaudhuri S, Vishwas P. Pathological Lung Patterns of COVID-19 and its Clinical Correlation to Disease Severity. Indian J Crit Care Med 2022;26(12):1285-1292.