Bronchiectasis is one of the indicators of severe coronavirus disease 2019 pneumonia
Since 2019, an epidemic of pneumonia of unknown cause occurred globally. Analysis of respiratory tract samples led to the identification of a novel coronavirus, named 2019 novel coronavirus (2019-nCoV). Epidemiological data showed that 2019-nCoV could spread rapidly from person to person, causing coronavirus disease-19 (COVID-19). The high infectivity of COVID-19 resulted in a rapid increase in cases, leading to a global pandemic. To date, 2019-nCoV has infected millions and caused hundreds of thousands of deaths worldwide. These numbers are updated daily and are expected to continue rising at a significant rate. COVID-19 has become a serious threat to global public health.
The increasing number of cases worldwide has led to a large-scale shortage of medical resources. Treatment classification based on the severity of patients’ conditions has been widely used to ensure the rational use of medical resources. However, some patients with mild initial symptoms experience rapid deterioration to asphyxia. Therefore, accurately predicting and evaluating the severity of illness upon admission is crucial. Computed tomography (CT) images can objectively show lung changes in COVID-19 patients, making CT a valuable tool for rapid diagnosis and assessment of COVID-19 pneumonia.
This study retrospectively collected data from pneumonia patients with confirmed COVID-19 admitted to a hospital in Wuhan City, Hubei Province, between January and March 2020. The study was approved by the Ethics Review Committee of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, and the need for informed consent was waived.
Confirmed 2019-nCoV infection was defined based on interim guidance from the World Health Organization. Throat swab specimens were collected and analyzed using real-time reverse transcription-polymerase chain reaction (RT-PCR). Only patients with positive laboratory test results were included, and those who did not undergo chest CT were excluded. During the study period, 90 patients with laboratory-confirmed 2019-nCoV infection admitted to designated tertiary hospitals in Wuhan were included. All patients recovered and were discharged after treatment. Standardized data forms were used to collect clinical data, which were reviewed by doctors treating COVID-19 patients on the front line.
Parameters assessed at hospital admission included demographic data (age and sex), clinical symptoms (fever, cough, sputum production, dyspnea or respiratory distress, weakness, myalgia, and pharyngalgia), and comorbidities (chronic obstructive pulmonary diseases [COPD], hypertension, diabetes, cardiovascular conditions, chronic renal or liver insufficiency, and malignancies). The severity of illness on admission was measured according to the Diagnosis and Treatment Plan of Coronavirus Disease (seventh edition).
All patients underwent chest CT immediately after hospitalization. Chest CT images were reviewed by two experienced radiologists in consensus. If a consensus could not be reached, a third experienced radiologist was consulted for the final decision. Radiologists were blinded to the patient’s status and the severity of clinical symptoms.
The types of lesions on chest CT images, such as ground-glass opacities (GGOs), consolidation, reticular patterns, nodular opacities, and bronchiectasis, were evaluated, along with the type of lesion distribution (unilateral/bilateral, solitary/multiple/diffuse). A GGO is defined as a hazy area of increased lung opacity with indistinct margins of pulmonary vessels on radiography but with preserved bronchial and vascular margins on CT. Consolidation is defined as a homogeneous increase in parenchymal attenuation that obscures vessel margins and airway walls. A nodular opacity is defined as a rounded opacity that is well or poorly defined. On CT, the diameter ratio of a normal bronchus to the accompanying pulmonary artery (measured from the outer wall to the opposite outer wall) is approximately 1:1. Bronchiectasis is defined as the diameter of the bronchus being larger than that of the accompanying pulmonary artery. Bronchial wall thickening, mucus plug, and bronchial shadow in peripheral lung tissue are also auxiliary signs.
In total, 90 patients were included, with 47 males and 43 females. The mean age was 55.1 ± 13.9 years. The initial throat swab test results were positive in 76 (87.4%) patients. Among these, 64 (73.6%) had mild or common disease, 23 (25.6%) had severe disease, and 3 (3.3%) had critical disease. The most common presenting symptoms were fever (90.2%) and cough (68.9%), and 28 (31.1%) patients showed rapid progression to dyspnea (the mean time from onset of illness to dyspnea was 1.4 ± 2.9 days). Hypertension (22.2%) and diabetes (11.1%) were the most common comorbidities. Two patients had COPD, one assessed as severe disease and the other as critical disease. None of the patients had a history of bronchiectasis.
Regarding CT findings, all patients presented with GGOs, and 70 (77.8%) patients had interstitial changes in their lungs. These were the most common findings. Additionally, 39 (43.3%) patients showed pulmonary consolidations, 18 (20.0%) showed local patchy shadowing, and 14 (15.6%) showed bronchiectasis. Other findings included bronchial wall thickening, small pleural effusion, and small pericardial effusion. Similar to chest imaging findings noted in viral pneumonia, bilateral GGOs and/or unilateral pulmonary consolidation were observed in the majority of patients.
The study further evaluated the correlation between CT findings and clinical severity. Bronchiectasis and pulmonary consolidation were associated with increased severity. A multivariable-adjusted model showed that these relationships persisted after controlling for age, sex, COPD, hypertension, diabetes, cardiovascular conditions, chronic renal or liver insufficiency, and malignancies. The odds ratio (OR) for bronchiectasis was 3.78, with a 95% confidence interval (CI) of 0.95–15.06 and a P-value of 0.050. For pulmonary consolidation, the OR was 24.91, with a 95% CI of 5.07–122.28 and a P-value of less than 0.001.
The study found that bronchiectasis on chest CT is observed more frequently in patients with severe COVID-19 disease than in those with mild or common COVID-19. The presence of bronchiectasis could be a useful marker for severe pulmonary damage caused by COVID-19. A recent autopsy report confirmed that the iliac bronchioles and terminal iliac bronchioles were filled with dense thick “mucus plugs” obstructing the lower respiratory tract. The exudation and necrosis of the bronchial mucosa lead to the accumulation and agglomeration of mucus in the bronchi. Based on chest CT findings and pathological results from the autopsy study, bronchiectasis may result from the formation of mucus plugs in COVID-19 patients. Further analysis of the biochemical changes involved in bronchiectasis is needed to clarify the mechanisms underlying this correlation.
Previous studies have also focused on CT findings in adults with COVID-19. Shi et al reported rapid evolution from focal unilateral GGOs to diffuse bilateral GGOs and the co-existence of consolidations within 1 to 3 weeks of COVID-19 onset. Guan et al extracted data from 1099 patients and found that GGO was the most common finding on chest CT upon initial admission.
The multivariable-adjusted model eliminates the possible impact of COPD on the prognosis of patients. However, due to the small number of patients with COPD, the association between COPD and the severity of COVID-19 requires further study.
Compared to chest radiography, chest CT is more sensitive for detecting GGOs and more effective in the early detection of COVID-19 pneumonia. Chest CT is easy to perform, fast, and highly sensitive for detecting COVID-19 pneumonia in the early stages. Therefore, it provides more accurate and timely information regarding diagnosis, severity, and treatment. In patients with COVID-19, bronchiectasis, GGOs, and pulmonary consolidation on chest CT were associated with severity. This is of great significance for the clinical diagnosis and severity staging of COVID-19 pneumonia. Chest CT can further help guide the provision of personalized and precise treatment.
doi.org/10.1097/CM9.0000000000001368
Was this helpful?
0 / 0