Lack of fever, normal radiological findings complicates diagnosis in some COVID-19 cases

Last Updated: 2020-02-28

By Gene Emery

(Reuters Health) - Patients infected with the COVID-19 virus can take many days to develop a fever, often don't present at the hospital with pneumonia and, when they are destined to die from the disease, it can take weeks, according to a new report from Chinese doctors detailing the clinical characteristics of 1,099 patients with laboratory-confirmed cases.

"Patients often present without fever, and many did not have abnormal radiologic findings," a team led by Dr. Nan-shan Zhong of Guangzhou Medical University reported in a study published online in The New England Journal of Medicine. "Severe illness occurred in 15.7% of the patients after admission to a hospital."

In 8.9% of patients, the infection "was detected before the development of viral pneumonia or viral pneumonia did not develop," the researchers said.

At the data cutoff point, only 5% of hospitalized patients had been discharged.

While the World Health Organization is estimating a death rate of 0.7% outside of China, the study found that 1.4% of the patients in the Chinese study died, with a mean interval between onset of symptoms and death of 15.4 days.

"Since patients who were mildly ill and who did not seek medical attention were not included in our study, the case fatality rate in a real-world scenario might be even lower," the China team said.

Seventeen percent of patients ultimately needed some type of mechanical ventilatory support and it took an average of 9.3 days for the infection to become bad enough to require a ventilator.

The average patient infected 2.2 other people and it typically took 4.0 days for symptoms to appear.

Fewer than half the people - 43.8% - had a fever when they were admitted, although that ratio grew to 88.7% during hospitalization.

Cough was a symptom in two thirds (67.8%) of the cases. Lymphocytopenia was present in 83.2% at the time of admission.

Smokers and former smokers were more likely to develop serious disease.

Although 7,736 people in China had been diagnosed with COVID-19 at the time of data cutoff, only 1,099 were studied because data on clinical symptoms and outcomes were available for that group.

Healthcare workers accounted for 3.5% of the patients.

Only 0.9% of patients were younger than age 15. An earlier report on the virus published by the Journal, involving a smaller number of patients, found that children were not falling ill from the virus for reasons that remain a mystery.

The rate of abnormal CT scans at the time of admission was 86.2%, with ground-glass opacity seen in 56.4% of patients and bilateral patchy shadowing seen in 51.8%. When the disease was severe, only 2.9% had no abnormality on a chest x-ray or CT scan. In non-severe cases, 17.9% showed no chest abnormality.

Among patients with severe disease, the cumulative risk of death, invasive mechanical ventilation or admission to the intensive care unit was 24.9%. It was 6.1% among all patients.

The median duration of hospitalization was 12.0 days, the researchers said.

The virus was detected in saliva, urine and the gastrointestinal tract (although few patients reported GI upset) so "these routes of potential transmission need to be investigated," they said.

SOURCE: https://bit.ly/2T6XGde The New England Journal of Medicine, online February 28, 2020.