COVID-19: What the illness looks like

By Dr. Liji Thomas, MDApr 2 2020

With increasing information about COVID-19 disease gathered first-hand, a more accurate picture of the clinical features is coming together.

How COVID-19 presents

So how does it start? State departments of health, and world health bodies, list the symptoms of COVID-19 as fever, a dry cough, sore throat, tiredness and shortness of breath. But clinicians would add many more.

For one, many cases have no symptoms at all, and such patients are asymptomatic carriers.

Others may have a reduced or absent sense of smell or taste, altered taste, nausea, diarrhea, and cardiac illnesses such as myocarditis, pericarditis or atrial fibrillation.

Gut symptoms are prevalent, though not always emphasized, occurring in almost half (49%) of all patients, according to some recent research published in The American Journal of Gastroenterology on 20 March. It lists symptoms such as loss of appetite in over 80% of 200 patients with COVID-19 and diarrhea in over a quarter (29%). Vomiting and abdominal pain are much less frequent, seen in 0.8% and 0.4%, respectively.

The researchers did note that the presence of gut symptoms was associated with a less favorable outcome, at 34% compared to 60% of patients without these features.

Coronavirus disease COVID-19 infection 3D medical illustration. Image Credit: Corona Borealis Studio / Shutterstock

The clinical course of COVID-19

According to Professor Louis Irving of the Royal Melbourne Hospital, the course of the illness varies tremendously. While many patients just get better without much treatment, others get worse. However, he says, “The deterioration can be a few days, even a week later, rather than a stepwise deterioration from the time of presentation.”

This is where it becomes concerning: patients who seem to have turned the corner suddenly go downhill rapidly. This is why Irving stresses that the course of this illness is not a smooth one.

ER physician shares knowledge of COVID-19 course

In a note from an emergency physician in New Orleans, the findings from the several hundred COVID-19 patients that have been seen personally by the writer are charted in chronological form, and appear to represent a realistic clinical picture of the progression of the illness:

Day 2 to day 11 – on average, around day 5, the patient has symptoms of the flu, including fever, dry cough, muscle pain (especially back pain), headache, nausea (but not often vomiting), abdominal pain and sometimes diarrhea, loss of appetite, loss of smell, and tiredness. Any of these, alone or in combination, can occur.

Day 5 – after these initial symptoms, the patient often has progressive shortness of breath because of viral pneumonia affecting both lungs.

Day 10 – those with severe illness appear to experience a ‘cytokine storm’ where a flood of cell chemicals is released from the infected cells as well as other immune cells recruited to help fight the attack. This both signals and promotes intense systemic inflammation. The resulting damage to the lung alveolar cells causes acute lung injury and multi-organ failure.

Such intensifying of symptoms could be due to either a fresh direct attack by the virus on the lungs or the result of the hyperactive immune response to the cytokine storm. Most fatalities are the result of acute lung injury, which adds to the seriousness of the warning.

With an acute lung injury, the vast and rich capillary network and the alveolar sacs in the lungs undergo damage because of viral injury, as well as the changes induced by severe reactive inflammation. The swelling of the lung caused by fluid accumulation, and its infiltration by millions of white cells, cause increased stiffness of the lungs. This hampers the normal diffusion of oxygen into the blood, leading to a lack of oxygen supply to the vital organs. Death is the result of hypoxia, therefore.

On the other hand, death could also be due to continuing viral damage or secondary bacterial pneumonia, or due to the worsening of other pre-existing conditions.

Overall, about 81% of patients only have mild symptoms. About 14% will develop severe shortness of breath, and 5% have a critical illness.

Earlier research confirmed

The post supports another paper published in the journal JAMA Network in February 2020. The latter describes a series of 138 patients in Wuhan, the place where it all began in China’s Hubei province. The median time to the first symptom to shortness of breath was five days in that study. The median period to admission in the hospital was seven days and to acute lung injury eight days. 26% in that series were ill enough to require intensive care, and the fatality rate was 4%.

Further studies in The Lancet describe several risk factors for severe COVID-19 illness: those who are older, and have underlying medical conditions like hypertension, diabetes and cardiovascular disease.

The take-home message

All the same, Irving says it is still a matter of debate whether the patients who suddenly deteriorate are those who were sicker to begin with, or just like other patients with mild illness. In the absence of such information, he says, “I’d make the recommendation that all patients should be encouraged to report any worsening, even if they initially appear to be getting better.” While such advice may scare some people, it has to be communicated plainly, if tactfully.

The long-term outcomes

Irving emphasizes that most people with COVID-19 do recover. He says their long-term outcome is likely to reflect that of other similar respiratory illnesses. Obviously, such information on COVID-19 will take years to accumulate.

From what is known, young patients who have no other medical condition and recover from mild illness are still at a higher risk of secondary bacterial infection for the next 3 months. Older patients have a higher risk of heart attacks over the next two years. Other than these, the average patient will not have many scars.

On the other hand, those who survive acute lung injury, or develop secondary bacterial pneumonia, may go on to experience permanent fibrosis of the lungs.