Medical Image of the Month: Viral Pneumonias

Figure 1. Pulmonary viral infection spectrum on thoracic CT scan in lung windows: A= Coronavirus NL63; B= Adenovirus; C= Influenza AH1 2009; D= COVID-19; E= Coronavirus HKU1; F= Influenza AH1 2009.

Numerous viruses, including the corona, influenza and adenoviruses can cause lower respiratory tract infection in adults (1). Viral pneumonia in adults can be classified into two clinical groups: so-called atypical pneumonia in otherwise healthy hosts and viral pneumonia in immunocompromised hosts. Until the COVID-19 pandemic, influenza virus types A and B caused most cases of viral pneumonia in immunocompetent adults. Immunocompromised hosts are susceptible to pneumonias caused by a wide variety of viruses including cytomegalovirus, herpesviruses, measles virus, and adenovirus. The CT imaging findings consist mainly of patchy or diffuse ground-glass opacity, with or without consolidation, and reticular areas of increased opacity, are variable and overlapping. The imaging findings in COVID-19 pneumonia are generally not distinctive compared to other viral pneumonias, including other coronaviruses such as SARS and MERS (2). A recent study systematically reviewed the longitudinal changes of CT findings in COVID-19 pneumonia. The results suggested that the lung abnormalities increase quickly after the onset of symptoms, peak around 6-11 days, and are followed by persistence of the findings.

Bacterial pneumonias may also take multiple forms and are sometimes difficult to radiographically separate from viral pneumonia (3). However, the presence of ground-glass opacities alone is unusual for a bacterial pulmonary infection. Rather, bacterial infections commonly present as areas of consolidation with air bronchogram formation, centrilobular nodules (often with branching configurations) and airway thickening.

Michael B. Gotway MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

References

1. Kim EA, Lee KS, Primack SL, et al. Viral pneumonias in adults: radiologic and pathologic findings. Radiographics. 2002 Oct;22 Spec No:S137-49. [CrossRef] [PubMed]
2. Wang Y, Dong C, Hu Y, Li C, Ren Q, Zhang X, Shi H, Zhou M. Temporal Changes of CT Findings in 90 Patients with COVID-19 Pneumonia: A Longitudinal Study. Radiology. 2020 Mar 19:200843. [CrossRef] [PubMed]
3. Panse PM, Jokerst CE, Gotway MB. May 2020 Imaging Case of the Month: Still Another Emerging Cause for Infiltrative Lung Abnormalities. Southwest J Pulm Crit Care. 2020. May 1. (in press). [CrossRef]

Cite as: Gotway MB. Medical image of the month: viral pnuemonias. Southwest J Pulm Crit Care. 2022;20(5):163-4. doi:  https://doi.org/10.13175/swjpcc028-20 PDF 

May 2020 Imaging Case of the Month: Still Another Emerging Cause for Infiltrative Lung Abnormalities

Prasad M. Panse MD

Clinton E. Jokerst MD

Michael B. Gotway MD

Department of Radiology

Mayo Clinic, Arizona

Scottsdale, Arizona 85054

Clinical History: A 46-year-old man with a history of well-controlled asthma presented to the Emergency Room with complaints of worsening non-productive cough for 4-5 days followed by fever to 104°F over the previous 3 days. The patient also complained of some chills and loose stools. The patient denied rhinorrhea, sore throat, congestion, and nausea or vomiting. The patient also denied illicit drug use, and drinks alcohol only occasionally and denied smoking.

The patient’s physical examination showed a pulse rate of 79 / minute and a respiratory rate of 18 / minute, although his blood pressure was mildly elevated at 149/84 mmHg; he was afebrile with a temperature of 97.7 °F (36.5 °C). The patient’s room air oxygen saturation was 98%. The physical examination showed some mild expiratory wheezes bilaterally, but was otherwise entirely within normal limits.

Which of the following represents the most appropriate step for the patient’s management? (Click on the correct answer to be directed to the second of twelve pages)

1. Obtain a complete blood count
2. Obtain a travel history
3. Obtain serum chemistries
4. Perform chest radiography
5. All of the above

Cite as: Panse PM, Jokerst CE, Gotway MB. May 2020 imaging case of the month: still another emerging cause for infiltrative lung abnormalities. Southwest J Pulm Crit Care. 2020;20(5):147-62. doi: https://doi.org/10.13175/swjpcc027-20 PDF