Pulmonary fibrosis as an outcome of COVID-19 pneumonia

In this study, we report three cases of persistent severe respiratory failure and radiological signs of diffuse pulmonary fibrosis in patients after COVID-19 related pneumonia. Chest CT criteria for a diagnosis of pulmonary fibrosis include the presence of traction bronchiectasis and parenchymal bands (linear opacities), as well as numerous small subpleural cystic air spaces (honeycombing). The study found that all cases of fibrosis were associated with such risk factors as male gender, old age, and multicomorbidity. Chest CT of one patient with acute respiratory distress syndrome showed radiographic characteristics of pulmonary fibrosis together with the presence of ground glass opacities (GGO) – the main CT feature of COVID-19 pneumonia. In two other patients, CT features of pulmonary fibrosis appeared in about 2 months after the hospital stay.Thus, pulmonary fibrosis is severe and rapidly progressive complication of COVID-19 pneumonia with a poor prognosis, especially in patients with multiple risk factors.

Real-life prevalence of progressive fibrosing interstitial lung diseases

The concept of progressive fibrosing interstitial lung disease (PF-ILD) has recently emerged. However, real-life proportion of PF-ILDs outside IPF is still hard to evaluate. Therefore, we sought to estimate the proportion of PF-ILD in our ILD cohort. We also determined the proportion of ILD subtypes within PF-ILD and investigated factors associated with PF-ILDs. Finally, we quantified interobserver agreement between radiologists for the assessment of fibrosis. We reviewed the files of ILD patients discussed in multidisciplinary discussion between January 1st 2017 and December 31st 2019. Clinical data, pulmonary function tests (PFTs) and high-resolution computed tomography (HRCTs) were centrally reviewed. Fibrosis was defined as the presence of traction bronchiectasis, reticulations with/out honeycombing. Progression was defined as a relative forced vital capacity (FVC) decline of ≥ 10% in ≤ 24 months or 5% < FVC decline < 10% and progression of fibrosis on HRCT in ≤ 24 months. 464 consecutive ILD patients were included. 105 had a diagnosis of IPF (23%). Most frequent non-IPF ILD were connective tissue disease (CTD)-associated ILD (22%), hypersensitivity pneumonitis (13%), unclassifiable ILD (10%) and sarcoidosis (8%). Features of fibrosis were common (82% of CTD-ILD, 81% of HP, 95% of uILD). After review of HRCTs and PFTs, 68 patients (19% of non-IPF ILD) had a PF-ILD according to our criteria. Interobserver agreement for fibrosis between radiologists was excellent (Cohen’s kappa 0.86). The main diagnosis among PF-ILD were CTD-ILD (36%), HP (22%) and uILD (20%). PF-ILD patients were significantly older than non-F-ILD (P = 0.0005). PF-ILDs represent about 20% of ILDs outside IPF. This provides an estimation of the proportion of patients who might benefit from antifibrotics. Interobserver agreement between radiologists for the diagnosis of fibrotic ILD is excellent.

Reversible Bronchiectasis in COVID-19 Survivors With Acute Respiratory Distress Syndrome: Pseudobronchiectasis

To retrospectively analyze whether traction bronchiectasis was reversible in coronavirus disease 2019 (COVID-19) survivors with acute respiratory distress syndrome (ARDS), and whether computed tomography (CT) findings were associated with the reversibility, 41 COVID-19 survivors with ARDS were followed-up for more than 4 months. Demographics, clinical data, and all chest CT images were collected. The follow-up CT images were compared with the previous CT scans. There were 28 (68%) patients with traction bronchiectasis (Group I) and 13 (32%) patients without traction bronchiectasis (Group II) on CT images. Traction bronchiectasis disappeared completely in 21 of the 28 (75%) patients (Group IA), but did not completely disappear in seven of the 28 (25%) patients (Group IB). In the second week after onset, the evaluation score on CT images in Group I was significantly higher than that in Group II (p = 0.001). The proportion of reticulation on the last CT images in Group IB was found higher than that in Group IA (p &lt; 0.05). COVID-19 survivors with ARDS might develop traction bronchiectasis, which can be absorbed completely in most patients. Traction bronchiectasis in a few patients did not disappear completely, but bronchiectasis was significantly relieved. The long-term follow-up is necessary to further assess whether traction bronchiectasis represents irreversible fibrosis.

Risk Factors Associated With Mortality in Hypersensitivity Pneumonitis: A Meta-analysis

Purpose: Hypersensitivity pneumonitis (HP), an immune-mediated form of diffuse parenchymal lung disease (DPLD), is triggered by inhalation of a wide variety of allergens in susceptible individuals. Several studies suggest that the death rate associated with this disease has increased significantly in recent years. This meta-analysis investigates the significant clinico-radiological characteristics which may be appraised as potential risk factors associated with disease mortality.Methods: Extensive literature search was conducted for original articles published between January 2009 and April 2021 through PubMed, Google Scholar, EMBASE, and Cochrane Library using the keywords: “hypersensitivity pneumonitis”, “hazard ratio” and “mortality”. Results: A total of 21 independent studies related to mortality of HP subjects could be identified. The combined results of univariate and multivariate analysis suggest that older age [univariate odds ratio (OR) 1.038 (1.028-1.048); multivariate OR 1.036, (1.025-1.046)], male subjects [univariate OR 1.508, (1.240- 1.834); multivariate OR 1.396, (1.004-1.943)], honeycombing [univariate OR 1.086 (1.065- 1.108); multivariate OR 1.121 (1.070- 1.175)] and traction bronchiectasis [univariate OR 1.141 (1.092- 1.192); multivariate OR 1.107 (1.048-1.169)] are significantly associated with mortality risk of HP subjects. Further, forced vital capacity (FVC), diffusing capacity for carbon monoxide (DLco), ground glass opacity (GGO) and mosaic attenuation were associated with lower risk of all-cause mortality. Although smoking status correlated with mortality risk in these patients, the findings appeared to be insignificant. Conclusion: Individual male subjects with older age and presence of extensive fibrosis, i.e., honeycombing and traction bronchiectasis experience an increased mortality risk.

Changes in pulmonary microcirculation after COVID-19

The endothelium is a tissue most vulnerable to the SARS-CoV-2 virus. Systemic endothelial dysfunction leads to the development of endothelitis which causes the main manifestations of the disease and systemic disturbance of microcirculation in various organs. Pulmonary microcirculatory damage, the most striking clinical manifestation, was the reason to perform SPECT to detect microcirculation disorders.Aim. To assess microcirculatory changes in the lungs of patients who had no previous respiratory diseases and had a COVID-19 infection at different times from the onset of the disease.Methods. SPECT data were analyzed in 136 patients who had a proven coronavirus infection of varying severity from May 2020 to June 2021.Results. All patients showed changes in microcirculation in the lungs in the post-COVID period. The severity of microcirculation disorders had a significant correlation (rs = 0.76; p = 0.01) with the degree of damage to the pulmonary parenchyma and an average correlation (rs = 0.48; p = 0.05) with the timing of the post-COVID period and the degree of residual lesions on CT (rs = 0.49; p = 0.01). The examined patients with persistent clinical complaints had pulmonary microcirculatory lesions, which may indicate the development of vasculitis, at all stages of the post-COVID period. Despite regression of the lesions confirmed by CT in 3 to 6 months after the acute COVID-19 infection, specialists from Russian and other countries report that 30–36% of patients develop pulmonary fibrosis. Similar changes were identified in 19.1% of the examined patients in our study.Conclusion. Microcirculation disorders are detected in all patients in the post-COVID period, irrespective of the severity according to CT. Progressive decrease in microcirculation in the lower parts of the lungs, local zones of hypoperfusion with the critically low accumulation of radiopharmaceuticals, persistent areas of compaction of the lung tissue (so-called “ground glass”), reticular changes, and the development of traction bronchiectasis, a decrease in the diffusion capacity of the lungs and alveolar volume may indicate fibrotic lesions with subsequent development of virus-associated interstitial lung disease.

CT findings in sequel of COVID-19 pneumonia and its complications: a pictorial review

A significant number of patients after initial recovery from COVID-19 continue to experience lingering symptoms of the disease that may last for weeks or even months. Lungs being the most commonly affected organ by COVID-19, bear the major brunt of the disease and thus it is imperative to be aware of the evolution of the pulmonary parenchymal changes over time. CT chest is the imaging modality of choice to evaluate post-COVID lungs. Persistent ground-glass opacities, septal thickening and parenchymal bands, crazy-paving, traction bronchiectasis and consolidation constitute the commonly encountered imaging patterns seen on CT in post COVID-19 lungs. Few vulnerable patients can develop lung fibrosis and show honeycombing on CT. Additionally, many complications like superadded infections (bacterial and fungal), pulmonary thromboembolism and pseudoaneurysm formation are also being reported. In the present pictorial review, we have tried to show the entire CT spectrum of sequelae of COVID-19 pneumonia and commonly associated infections and vascular complications.

Cough in the post COVID period: clinical examples

Among the extensive list of manifestations of post COVID syndrome, cough is often found. Most researchers interpret its character as post infection. In some patients, post infection cough becomes productive, and combined mucoactive therapy is required for effective treatment. Since the onset of the pandemic, clinical descriptions of spontaneous pneumothorax have accumulated in the literature. The risk of this complication is present even in patients who are not burdened with chronic lung diseases, as well as those who are breathing spontaneously. The study of the mechanisms of development of spontaneous pneumothorax in COVID-19 is necessary for the development of further therapeutic and preventive measures. Traction bronchiectasis occurs in 27 – 52.5% of cases of new coronavirus infection. Changes in the structure of the bronchi predispose to chronic cough and recurrent infections. Respiratory viral infection has been considered in the past as a trigger for bronchial asthma. There is controversy over the new coronavirus. Asthma has been suggested as a protective factor in COVID-19, due to the specific inflammation profile that protects patients. In some patients who have had COVID-19, the cough is due to hyperventilation syndrome. To explain it, a hypothesis of impaired respiratory control was proposed. The paper presents clinical examples illustrating a wide range of pathological conditions accompanied by cough. Possible relationships between cough and previous coronavirus infection are discussed.

Role of Chest CT in COVID-19

In December 2019, a disease attributed to a new severe acute respiratory syndrome coronavirus 2, and named coronavirus disease 2019 (COVID-19), broke out in Wuhan, China and has spread rapidly throughout the world. CT has been advocated in selected indications as a tool toward rapid and early diagnosis. The CT patterns of COVID-19 include ground glass opacities GGO, consolidation, and crazy paving. Additional signs include a “rounded morphology” of lesions, vascular enlargement sign, nodules, and fibrous stripe. Signs of healing and organization include subpleural bands, a reticular pattern, reversed halo sign and traction bronchiectasis. Cavitation and tree in bud signs are absent and pleural effusions are rare. There is a high incidence of pulmonary embolism associated with COVID-19. CT findings in COVID-19 appear to follow a predictable timeline with maximal involvement approximately 6–11 days after symptom onset. The stages of evolution include early stage (days 0–4) with GGO being the predominant abnormality, progressive stage (days 5–8) with increasing crazy paving; and peak stage (days 9–13) with predominance of consolidation and absorption phase (after day 14) with gradual absorption of consolidation with residual GGO and subpleural bands. CT findings in COVID-19 have a high sensitivity and low specificity, determined to be 98% and 25% in a retrospective study of 1014 patients. The low specificity of CT for the diagnosis of COVID-19 pneumonia is due to the overlap of CT findings with other viral pneumonias and other infections, lung involvement in connective tissue disorders, drug reaction, pulmonary edema, and hemorrhage.

COVID-19 versus H1N1: challenges in radiological diagnosis—comparative study on 130 patients using chest HRCT

Background During the current second wave of COVID-19, the radiologists are expected to face great challenges in differentiation between COVID-19 and other virulent influenza viruses, mainly H1N1. Accordingly, this study was performed in order to find any differentiating CT criteria that would help during the expected clinical overlap during the current Influenza season. Results This study was retrospectively conducted during the period from June till November 2020, on acute symptomatic 130 patients with no history of previous pulmonary diseases; 65 patients had positive PCR for COVID-19 including 50 mild patients and 15 critical or severe patients; meanwhile, the other 65 patients had positive PCR for H1N1 including 50 mild patients and 15 critical or severe patients. They included 74 males and 56 females (56.9%:43.1%). Their age ranged 14–90 years (mean age 38.9 ± 20.3 SD). HRCT findings were analyzed by four expert consultant radiologists in consensus. All patients with COVID-19 showed parenchymal or alveolar HRCT findings; only one of them had associated airway involvement. Among the 65 patients with H1N1; 56 patients (86.2%) had parenchymal or alveolar HRCT findings while six patients (9.2%) presented only by HRCT signs of airway involvement and three patients (4.6%) had mixed parenchymal and airway involvement. Regarding HRCT findings of airway involvement (namely tree in bud nodules, air trapping, bronchial wall thickening, traction bronchiectasis, and mucous plugging), all showed significant p value (ranging from 0.008 to 0.04). On the other hand, HRCT findings of parenchymal or alveolar involvement (mainly ground glass opacities) showed no significant relation. Conclusion HRCT can help in differentiation between non-severe COVID-19 and H1N1 based on signs of airway involvement.