Organising pneumonia manifesting as a late-phase complication of COVID-19.

Acute COVID-19 usually lasts 4 weeks from the onset of symptoms. We report two cases of COVID-19-associated organising pneumonia (OP) occurring beyond 4 weeks from the acute onset of symptoms. Both tested positive for SARS reverse transcription-PCR 2 months before presentation with a resolution of respiratory symptoms. The first case presented with residual fatigue and worsening exertional dyspnoea. Chest CT revealed an OP pattern. The second case presented with worsening cough and new-onset pleuritic chest pain with persistent radiological consolidation. A transbronchial lung biopsy confirmed OP. Both patients responded well to 12 weeks of steroid therapy. This case illustrates the rare presentation of OP as a late sequela of COVID-19 and the good response to steroid therapy.

[Update 2021: Pulmonary Sequelae of COVID-19 Pneumonia]. / Update 2021: Pulmonale Folgen nach COVID-19-Pneumonie.

Acute COVID-19 pneumonia may result in persistent changes with various imaging and histopathological patterns, including organizing pneumonia and pulmonary fibrosis. In addition, SARS-CoV-2 infection is associated with increased risk of pulmonary vascular endothelialitis and thrombosis. Herein, current findings on pulmonary consequences of COVID-19 with implications for clinical management are summarized based on a selective literature review.

Comparison of Chest CT Findings of COVID-19, Influenza, and Organizing Pneumonia: A Multireader Study.

BACKGROUND. Previous studies compared CT findings of COVID-19 pneumonia with those of other infections; however, to our knowledge, no studies to date have included noninfectious organizing pneumonia (OP) for comparison. OBJECTIVE. The objectives of this study were to compare chest CT features of COVID-19, influenza, and OP using a multireader design and to assess the performance of radiologists in distinguishing between these conditions. METHODS. This retrospective study included 150 chest CT examinations in 150 patients (mean [± SD] age, 58 ± 16 years) with a diagnosis of COVID-19, influenza, or non-infectious OP (50 randomly selected abnormal CT examinations per diagnosis). Six thoracic radiologists independently assessed CT examinations for 14 individual CT findings and for Radiological Society of North America (RSNA) COVID-19 category and recorded a favored diagnosis. The CT characteristics of the three diagnoses were compared using random-effects models; the diagnostic performance of the readers was assessed. RESULTS. COVID-19 pneumonia was significantly different (p < .05) from influenza pneumonia for seven of 14 chest CT findings, although it was different (p < .05) from OP for four of 14 findings (central or diffuse distribution was seen in 10% and 7% of COVID-19 cases, respectively, vs 20% and 21% of OP cases, respectively; unilateral distribution was seen in 1% of COVID-19 cases vs 7% of OP cases; non-tree-in-bud nodules was seen in 32% of COVID-19 cases vs 53% of OP cases; tree-in-bud nodules were seen in 6% of COVID-19 cases vs 14% of OP cases). A total of 70% of cases of COVID-19, 33% of influenza cases, and 47% of OP cases had typical findings according to RSNA COVID-19 category assessment (p < .001). The mean percentage of correct favored diagnoses compared with actual diagnoses was 44% for COVID-19, 29% for influenza, and 39% for OP. The mean diagnostic accuracy of favored diagnoses was 70% for COVID-19 pneumonia and 68% for both influenza and OP. CONCLUSION. CT findings of COVID-19 substantially overlap with those of influenza and, to a greater extent, those of OP. The diagnostic accuracy of the radiologists was low in a study sample that contained equal proportions of these three types of pneumonia. CLINICAL IMPACT. Recognized challenges in diagnosing COVID-19 by CT are furthered by the strong overlap observed between the appearances of COVID-19 and OP on CT. This challenge may be particularly evident in clinical settings in which there are substantial proportions of patients with potential causes of OP such as ongoing cancer therapy or autoimmune conditions.