A spark of hope: histopathological and functional recovery after critical COVID-19

Exploring the pathologist's role in understanding COVID-19: from pneumonia to long-COVID lung sequelae

The crucial role of pathologists in enhancing our understanding of SARS-CoV-2-related disease, from initial pneumonia manifestations to persistent long COVID lung symptoms, is the focus of this review. Pathological explorations have offered unprecedented insights into the early stages of severe COVID-19, shedding light on the interplay between the virus and subsequent complications, thereby shaping clinical approaches. Growing interest is directed to residual lung abnormalities of COVID-19 survivors. Although various radiological studies reported long-lasting pulmonary changes (e.g., ground glass opacities, reticulations, and bronchiectasis), the true incidence of pulmonary fibrosis and corresponding pathological findings in these patients remains largely unknown. There are a few high-impact and knowledgeable works on late complications in COVID-19 survivors, several coming from explant or autopsy cases, and rare cases from in vivo sampling. The study of biopsy samples has further deepened our knowledge of the aftermath of COVID-19 on lung tissue, uncovering alterations at the cellular level and shifts in vascular and epithelial dynamics. Despite the substantial progress made, future research is needed to devise a uniform strategy for interpreting lung biopsies, with a focus on leveraging advanced tools such as molecular and digital pathology techniques, along with artificial intelligence.

A Systematic Review of Chest Imaging Findings in Long COVID Patients

Long COVID is the persistence of one or more COVID-19 symptoms after the initial viral infection, and there is evidence supporting its association with lung damage. In this systematic review, we provide an overview of lung imaging and its findings in long COVID patients. A PubMed search was performed on 29 September 2021, for English language studies in which lung imaging was performed in adults suffering from long COVID. Two independent researchers extracted the data. Our search identified 3130 articles, of which 31, representing the imaging findings of 342 long COVID patients, were retained. The most common imaging modality used was computed tomography (CT) (N = 249). A total of 29 different imaging findings were reported, which were broadly categorized into interstitial (fibrotic), pleural, airway, and other parenchymal abnormalities. A direct comparison between cases, in terms of residual lesions, was available for 148 patients, of whom 66 (44.6%) had normal CT findings. Although respiratory symptoms belong to the most common symptoms in long COVID patients, this is not necessarily linked to radiologically detectable lung damage. Therefore, more research is needed on the role of the various types of lung (and other organ) damage which may or may not occur in long COVID.

One-year evolution of DLCO changes and respiratory symptoms in patients with post COVID-19 respiratory syndrome

Purpose

During a follow-up program of patients admitted for COVID-19 at our non-ICU Unit, we found that 37% of them had decreased diffusing lung capacity for carbon monoxide (DLCO) 3–6 months after discharge. This prospective observational study aimed to evaluate the evolution of changes in DLCO and respiratory symptoms at the 1-year follow-up visit.

Methods

Seventeen (mean age 71 years; 8 males) of 19 eligible patients (DLCO < 80% of predicted at the 3–6 months follow-up visit) completed the 1-year follow-up visit. One patient refused to participate and 1 patient had died 3 months earlier from myocardial infarction. The visit included a self-reported structured questionnaire, physical exam, blood tests, ECG, and spirometry with DLCO.

Results

Mean DLCO was significantly improved at the 1-year visit (from 64% of predicted at 3–6 months to 74% of predicted at 1 year; P = 0.003). A clinically significant increase in DLCO (10% or greater) was observed in 11 patients (65%) with complete normalization (> 80% of predicted) in 6 (35%); in the other 6 (35%) it remained unchanged. The prevalence of exertional dyspnea (65–35%, P = 0.17), cough (24–18%, P = 1), and fatigue (76–35%, P = 0.04) decreased at the 1-year visit.

Conclusion

These results suggest that DLCO and respiratory symptoms tend to normalize or improve 1 year after hospitalization for COVID-19 in most patients. However, there is also a non-negligible number of patients (about one-third) in whom respiratory changes persist and will need prolonged follow-up.