950: Update on COVID-19

A study published in The Lancet Infectious Diseases showed that the predominant pattern of lung lesions in patients with COVID-19 patients was diffuse alveolar damage.

Luca Carsana, at Papa Giovanni XXIII Hospital, Bergamo, Italy, and colleagues assessed lung tissue samples from 38 patients who died from COVID-19 in 2 hospitals in northern Italy from February 29, 2020, to March 24, 2020.

Investigators obtained a median of 7 tissue blocks from each lung, selecting the most representative areas as seen at macroscopic examination. In an attempt to better characterize the inflammatory infiltrate, immunohistochemical staining was done on the most representative areas of randomly selected cases for inflammatory infiltrate and cellular components, including staining with antibodies against CD68, CD3, CD45, CD61, TTF1, p40, and Ki-67.

Lungs of all patients were heavy, congested, and edematous, with patchy involvement. Histological examination revealed features of exudative and early or intermediate proliferative phases of diffuse alveolar damage, which included capillary congestion and necrosis of pneumocytes in all cases, hyaline membranes in 33 cases, interstitial and intra-alveolar edema in 37 cases, type 2 pneumocyte hyperplasia in all cases, squamous metaplasia with atypia in 21 cases, and platelet-fibrin thrombi in 33 cases.

Hyaline membrane formation and pneumocyte atypical hyperplasia are common. It is important to note that the presence of platelet-fibrin thrombi in small arterial vessels is consistent with coagulopathy, which is common in patients with COVID-19 and should be among the key targets of therapy.

The patients had a mean age of 69 years and most (87%) were male. Time spent in the intensive care unit or intermediate medical ward varied between 1 day and 23 days. At the time of hospitalization, all patients had clinical and radiological features of interstitial pneumonia. Of the 26 patients with available D-dimer results, all had high levels (>10 × the upper reference limit). Mean time from symptom onset to death was 16 days.

[SOURCE: The Lancet Infectious Diseases]

Dr KK Aggarwal

President CMAAO