In 2019, a novel coronavirus, namely, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was linked to several cases of pneumonia. The rapid spread of this virus caused the coronavirus disease 2019 (COVID-19) pandemic. Even today, there is no specific treatment for SARS-CoV-2 infection. Typically, individuals infected with this virus are recommended isolation; however, severely infected patients might require oxygen support, invasive mechanical ventilation, steroid administration, antibiotic treatment for secondary bacterial infections, and fluid management.
Study: Tomographic findings and mortality in patients with severe and critical pneumonia with COVID-19 diagnosis. Image Credit: Komsan Loonprom/Shutterstock
Background
Computed tomography must be considered for diagnosis in patients with suspected pneumonia. The pulmonary tomographic images of patients with SARS-CoV-2 pneumonia revealed a multifocal ground-glass pattern that was peripherally distributed. These patterns were irregular, with a posterior or lower lobe predilection.
Imaging diagnosis of patients with atypical pneumonia is difficult because around 17% of COVID-19 patients with mild pneumonia-like symptoms do not exhibit pulmonary tomographic findings upon hospital admission.
A recent Respiratory Medicine Case Reports study reported the pulmonary tomographic findings in severely infected COVID-19 patients with critical pneumonia. Furthermore, this study aimed to determine mortality at 30 days in this group of patients, along with patients with acute respiratory distress syndrome (ARDS) and those suffering from different levels of lung disease.
About the study
This observational and retrospective study included patients admitted to Mexican hospitals, between June 2020 and March 2021, with severe SARS-CoV-2 pneumonia infection. The cohort comprised adult patients of both genders. Additionally, these patients had a contrasted chest computed tomography done during the time of sample collection for PCR to confirm COVID-19 diagnosis. In addition to PCR-confirmed SARS-CoV-2 infection, patients' detailed information on disease progression up to 30 days of hospitalization was included.
Demographic variables, including age, sex, weight, height, clinical variables (e.g., comorbidities and duration of hospital stay), and therapeutic management were obtained from medical records. The health conditions of the patients were assessed via the Sequential Organ Failure Assessment (SOFA), the Charlson comorbidity index (CCI), and the Acute Physiology and Chronic Health Evaluation (APACHE IV).
The blinded radiological classification was used to classify CT scans indicative of COVID-19 and non-COVID-19 infection. The tomographic findings were categorized as ground-glass pattern, presence of ganglia, consolidation pattern, vascular thickening pattern, nodular pattern, and presence of thrombosis.
Study findings
A consecutive case series of 490 patients with COVID-19 were evaluated, along with the computed tomography and different disease-severity scales to determine whether a patient would require mechanical ventilation support and their mortality risk at 30 days. It was observed that SOFA, APACHE IV, CCI, and the pulmonary damage severity index could positively predict the need for invasive mechanical ventilation.
No statistically different survival rate was observed between patients severely infected with pneumonia and COVID-19, requiring invasive mechanical ventilation support, and those who did not. Nevertheless, 84.35% of patients with a higher pulmonary damage severity index died within 30 days of hospital admission. However, 25.91% of patients with moderate lung damage and 2.42% with mild lung damage also died within the study period.
A previously conducted comparative study reported that tomographic findings related to viral pneumonia due to SARS-CoV-2 infection exhibited a greater incidence of peripheral lesions, presence of fine reticular opacities, ground-glass opacities, vascular thickening pattern, compared to non-COVID-19 infection. In contrast, pleural effusion, central and peripheral distribution, and lymphadenopathies were more frequently found in non-COVID-19 than SARS-CoV-2 infection.
In the present study, 89.80% of patients exhibited ground-glass opacities, followed by radiologic consolidation sign (81.63%), vascular thickening pattern (42.45%), lymphadenopathies (37.55%), pleural effusion (14.90%), and pulmonary thrombosis. (2.65%). Additionally, 91.02% of patients exhibited bilateral lesions, 85.51% peripheral lesions, and 75.92% basal lobe lesions.
It was observed that a higher pulmonary damage severity index indicated the requirement for mechanical ventilation. Some of the key factors associated with severe and critical pneumonia due to COVID-19 were age, diabetes, and chronic obstructive pulmonary disease.
Study limitations
The lack of radiological follow-up is a key limitation of this study. Due to this data shortcoming, the authors could only interpret the initial radiological evaluation and not the disease progression. Another limitation of the study cohort is that some participants received prior treatment with corticosteroids and antibiotics, which could influence the tomographic findings. As co-infection could confound the CT results, it was not considered. Lung biopsies were not conducted to confirm the tomographic findings. Nevertheless, the current study linked lung damage and acute respiratory distress syndrome with CT severity index and mortality at 30 days.
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