Can the prevalence of mediastinal lymphadenopathy in infected patients mean anything for the treatment of COVID-19? Authors of a study titled ‘Association of Mediastinal Lymphadenopathy with COVID-19 Prognosis’ highlight the possibility. Here is a summary of their research and findings.

Two papers published in The Lancet Infectious Diseases (2020) identify the prevalence rate of mediastinal lymphadenopathy in patients with severe COVID-19. While both studies had different approaches and different results, is it possible to use the prevalence rate to determine the severity of the infection? Is it an atypical feature, which if identified can help in the prognosis of COVID-19? The paper titled ‘Association of Mediastinal Lymphadenopathy with COVID-19 Prognosis’ presents research by Francesco S., Andrea C., Lorenzo M., et. al., to seek answers. [1]

The researchers refer to a paper previously published in The Lancet – ‘Mediastinal Lymphadenopathy in Patients with Severe COVID-19’. [2] The paper describes a study done on 15 infected patients, who were admitted in the ICU for COVID-19. The prevalence rate of lymphadenopathy was found to be as high as 66%. However, owing to the small sample size, it was concluded that further research was needed.

Presenting their own study, authors Francesco S., Andrea C., Lorenzo M., et. al., reviewed CT scans of 410 COVID-19 patients in the emergency department of hospitals in Lombardy, Italy. However, they identified a prevalence rate of only 19% in their patients.

Why the difference?

In their paper, the authors explain the difference by drawing a comparison between the two studies.

First is the sample size, of course. Also, the two cohorts studied are at different stages in terms of the treatment; while the older study was conducted on a group of 15 patients wo were already in the ICU, the cohort of 410 patients in this study presented to the emergency department. This means the severity of COVID-19 infection was also low in that (second) group.

The second study is based on the CT scans of the patients, whereas the first study was based on the data of the patients available in the ICU.

A look at the research findings:

• 76 patients had mediastinal lymphadenopathies; making the prevalence rate 19%
• 60 patients from the entire cohort were admitted to the ICU and only 15 of them had lymphadenopathies while in the emergency department
• Patients demonstrating a crazy paving pattern in their CT scan (33 of 106 patients) had more frequent lymphadenopathies at admission when compared to those without the pattern (43 of 304 patients) and likewise in patients who died during hospitalisation (37 of 136 patients) in comparison to those who were discharged (39 of 274)

Conclusion

A lower lymphadenopathy prevalence rate (found in the second study) is said to be due to the low severity of the COVID-19 infection in patients. According to the authors, although the prevalence was lower, it was still three times higher than estimates reported for other populatopms.

Therefore, the study concluded that lymphadenopathy can be defined as a “not-atypical” feature of COVID-19 and can be considered as a parameter to gauge the severity of the infection. However, they suggest further investigation to assess the pathophysiological correlation with the new coronavirus infection and to use this information for the clinical treatment of COVID-19 patients.

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