Studies profile lung changes in asymptomatic COVID-19, viral loads in patient samples
Mary Van Beusekom | News Writer | CIDRAP News
Feb 25, 2020
In new research developments, a team from Wuhan, China, reports that even asymptomatic patients with COVID-19 pneumonia have abnormal lung findings on computed tomography (CT), and a group from Beijing noted that viral loads from infected patients appear to peak 5 to 6 days after symptom onset.
Both reports appeared yesterday in The Lancet Infectious Diseases.
Images of disease at different points
The authors of the first study described chest CT findings from 42 men and 39 women admitted to one of two hospitals in Wuhan from December 20, 2019, to January 23, 2020, with COVID-19 pneumonia. All patients (mean age, 49.5 years) had a wide range of abnormal lung changes that spread rapidly from focused areas of excess fluid in one lung to diffuse buildup in both lungs.
Patients were grouped based on the length of time between the emergence of symptoms and first CT scan: group 1 (asymptomatic patients); group 2 (scans within seven days of symptom onset); group 3 (scans 8 days to 2 weeks after symptom onset); and group 4 (scans 15 days to 3 weeks after symptom onset).
Radiologists at the two hospitals, Wuhan Jinyintan Hospital and Union Hospital of Tongji Medical College, recorded and compared the patients' clinical and laboratory findings and co-existing diseases at initial and follow-up CT scans.
Wide range of lung abnormality patterns
Different radiolographic patterns emerged at different points of the disease. The mean number of affected lung segments was 10.5: 2.8 in group 1, 11.1 in group 2, 13.0 in group 3, and 12.1 in group 4. The right lower lobe of the lung had a slight tendency toward involvement.
In asymptomatic patients, 60% had abnormalities confined to one lung, while 90% of group 2 patients had abnormalities in both lungs. Those in groups 3 and 4 showed more mixed patterns and areas where fluid had replaced the air in the lung, leading to swelling and hardening of tissues.
This study helped further characterize CT findings in the lungs of patients with COVID-19 pneumonia. With development of acute respiratory distress syndrome as few as 9 days after symptom onset, the researchers say that prompt diagnosis and treatment are paramount. "Combining assessment of imaging features with clinical and laboratory findings could facilitate early diagnosis of COVID-19 pneumonia," they wrote.
A diagnostic dilemma
In a commentary in the same journal, three radiologists from the University of Hong Kong said the varied presentations pose challenges when diagnosing COVID-19 pneumonia.
"This small number of individuals with COVID-19 pneumonia poses a diagnostic dilemma given the varied manifestations, the experts wrote.
"There is more to be learnt about this novel contagious viral pneumonia; more research is needed into the correlation of CT findings with clinical severity and progression, the predictive value of baseline CT or temporal changes for disease outcome, and the sequelae of acute lung injury induced by COVID-19," they added.