|Ahead of print publication
Atypical chest radiological feature in a patient with nCOVID-19
M Vishnu Sharma1, N Anupama2
1 Department of Respiratory Medicine, A J Institute of Medical Sciences and Research Centre, Mangalore, Karnataka, India
2 Department of Physiology, Kasturba Medical College, Mangalore Manipal Academy of Higher Education, Manipal, Karnataka, India
|Date of Submission||25-May-2021|
|Date of Decision||06-Dec-2021|
|Date of Acceptance||26-Dec-2021|
Department of Physiology, Kasturba medical college, Mangalore, Manipal academy of higher education, Manipal, Karnataka
Source of Support: None, Conflict of Interest: None
Classical high-resolution computed tomography (HRCT) pattern in nCOVID-19 pneumonia is bilateral, basal, peripheral, subpleural, bronchopneumonia. Ground-glass opacities and consolidation are the most common initial radiological findings. However, chest computed tomography (CT) should not be used as an independent diagnostic tool to exclude or confirm COVID-19. CT is not a standard diagnostic tool for the diagnosis of COVID-19, but CT findings help to suggest the diagnosis in the appropriate setting. Chest CT findings should be correlated with epidemiologic history, clinical presentation, and reverse transcriptase–polymerase chain reaction (RT-PCR) test results. Many other diseases can mimic nCOVID-19 in HRCT and vice versa. We report an atypical radiological feature in RT-PCR-confirmed nCOVID-19 pneumonia case. HRCT showed unilateral peripheral ground-glass opacity. Atypical HRCT features in nCOVID-19 described in literature include central involvement, peribronchovascular involvement, isolated upper lobe involvement, nodular opacities, lobar consolidation, solitary opacity, unilateral lung involvement, mediastinal adenopathy, cavitory lesions, pleural and pericardial effusion, and subpleural sparing. When radiological manifestations are atypical, diagnosis of nCOVID-19 pneumonia should be by exclusion of other causes for the radiological abnormality.
Keywords: Atypical chest radiological feature, nCOVID-19 pneumonia, unilateral peripheral ground-glass opacity
| Introduction|| |
High-resolution computed tomography scan (HRCT) of the thorax is useful in patients with high pretest probability of nCOVID-19 pneumonia when reverse transcriptase–polymerase chain reaction (RT-PCR) report is negative and in symptomatic patients with hypoxia for rapid presumptive diagnosis as RT-PCR report usually takes 24 h. Classical HRCT pattern in nCOVID-19 pneumonia is bilateral, basal, peripheral, subpleural, bronchopneumonia. Ground-glass opacities and consolidation are the most common initial radiological findings.
However, chest CT should not be used as an independent diagnostic tool to exclude or confirm COVID-19. CT is not a standard diagnostic tool for the diagnosis of COVID-19, but CT findings help to suggest the diagnosis in the appropriate setting. Chest CT findings should be correlated with epidemiologic history, clinical presentation, and RT-PCR test results. Many other diseases can mimic nCOVID-19 in HRCT and vice versa. We report an atypical radiological feature in RT-PCR-confirmed nCOVID-19 pneumonia case.
| Clinical Presentation|| |
A 47-year-old male was admitted with a history of dry cough and mild exertional breathlessness for 2 days. He had fever and sore throat which started 7 days back, lasted for 2 days. Fever was associated with generalized body ache and fatigue. He had no other symptoms. He had no past history of any lung disease or respiratory symptoms. He had no other illness in the past. He was a nonsmoker, he had no addictions. He was not on any previous regular medications. His daughter, aged 14, had similar symptoms 4 days before him. Her RT-PCR for nCOVID-19 was positive.
On admission, his respiratory rate was 20/min and oxygen saturation was 94% on room air which reduced to 88% after 2-min walk. In view of his contact history and symptoms, nCOVID-19 pneumonia was suspected.
Rapid antigen test for nCOVID-19 was negative. RT-PCR for nCOVID-19 was sent. His chest X-ray [Figure 1] appeared normal. RT-PCR for nCOVID-19 was sent, the report was expected in 2 days as the sample load was high. Hence, a high-resolution CT scan of the thorax was done to identify lung involvement and risk stratification [Figure 2] and [Figure 3]. CT scan showed ground-glass opacity in the left lower lobe.
|Figure 3: Axial view showing peripheral ground glass opacities in left lower lobe|
Click here to view
Causes for unilateral peripheral ground-glass opacity include infections which can be due to any microbial infection and alveolar hemorrhage due to trauma. Other usual causes for ground-glass opacities lead to bilateral abnormalities. He had no history of chest trauma. He had no underlying predisposing condition to suspect alveolar hemorrhage.
| Outcome, Follow-Up, and Discussion|| |
Hence, a presumptive diagnosis of nCOVID-19 bronchopneumonia was made and treatment was initiated. His RT-PCR report for nCOVID-19 came as positive after 2 days. Hence, the diagnosis was confirmed. He made an uneventful recovery with supplemental oxygen, remdesivir, steroids, anticoagulant, and symptomatic treatment.
With contact history and typical symptoms, the diagnosis was easy in this patient. When symptoms and history are not typical, or RT-PCR for nCOVID-19 is negative, unilateral ground-glass opacity in a patient with nCOVID-19 pneumonia may lead to a diagnostic dilemma. Diagnosis in such cases will be by exclusion of other causes for the similar radiological picture. In cases where RT-PCR is negative, raised antibody titers for nCOVID-19 will help to establish the diagnosis.
A normal CT excludes nCOVID-19 bronchopneumonia. The proportion of false-positive or false negative chest CT examination results in covid 19 bronchopneumonia is substantial It is due to overlapping imaging features in covid with numerous other diseases, including other viral pneumonias. The positive predictive value for HRCT in diagnosis of nCOVID-19 bronchopneumonia is low (1.5% to 30.7%) in low-prevalence regions, and the negative predictive value ranged from 95.4% to 99.8% for nCOVID-19 pneumonia. Pooled sensitivity and specificity for chest CT for the diagnosis of covid 19 bronchopneumonia is 94% to 96% and 37%, respectively.
Atypical radiological features can occur in some patients with nCOVID-19 pneumonia. Atypical HRCT features include central involvement, peribronchovascular involvement, isolated upper lobe involvement, nodular opacities, lobar consolidation, solitary opacity, unilateral lung involvement, mediastinal adenopathy, cavitory lesions, pleural and pericardial effusion, and subpleural sparing. Awareness about these atypical findings is important to avoid misdiagnosis. Some of these CT features such as cavitory lesion, mediastinal adenopathy, pleural, and pericardial effusion may be due to complications during the course of the disease or coexistent diseases. When radiological manifestations are atypical, diagnosis of nCOVID-19 pneumonia should be by exclusion of other causes for the radiological abnormality. Correlation of CT findings with epidemiologic history, clinical presentation, and RT-PCR test results or in later stages antibody titers will help in confirming or excluding the diagnosis.
| Conclusion|| |
Atypical manifestations in CT scans can occur in some patients with nCOVID-19 bronchopneumonia. Correlation of chest CT scan findings with epidemiologic history, clinical presentation, RT-PCR test result, and exclusion of other causes for a similar radiological abnormality will help to establish a diagnosis when chest CT findings are atypical.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]