As medical understanding of Covid-19 develops globally, studies are increasingly indicating that the condition can present in widely diverse ways.
Dr Adri Kok, a specialist physician and president of both the International Society for Internal Medicine and the Faculty of Consulting Physicians of South Africa, says in addition to asymptomatic (showing no symptoms) carriers of the virus, it has been observed that some patients do not exhibit the respiratory symptoms (cough, shortness of breath, and a sore throat) that are most typical of Covid-19, and yet they develop sudden and potentially life-threatening complications arising as a result of the viral infection.
Dr Kok, who practises at Netcare Union and Netcare Clinton hospitals in Alberton, says that internationally, cases have been documented where patients present for the first time in an emergency setting with stroke, heart attack or various types of organ failure, and testing then reveals these patients to be Covid-19 positive.
“There are reports of even young people suffering a stroke, which occurs when a part of the brain is deprived of oxygen due to a blood clot, as a first indication that they have Covid-19.
“Although this virus primarily affects the upper airway and then the lungs due to droplet spread, Covid-19 may set in motion a series of reactions in the body, which may attack the small blood vessels that are crucial to the functioning of other organs including the heart, kidneys, and brain,” she says.
Dr Kok explains that sometimes the body has an overzealous reaction to an infection, known as a “cytokine storm”, which can lead to serious complications in some cases where people have contracted Covid-19.
Cytokines are proteins that our bodies release to communicate with various cells to co-ordinate bodily responses, as is the case when our immune system stimulates inflammation to fight infection, or clotting to help repair damaged tissues.
“It has been suggested that in some Covid-19 patients who progress to a more advanced stage of the illness, a cytokine storm causes a physiological change in the pneumocytes of the lungs and this then has a pro-thrombotic or clot-causing effect, potentially leading to abnormal clotting in small blood vessels. This blood clotting is known as thrombosis,” she says.
Apart from stroke, Covid-19 positive patients can also present with cardiovascular damage such as acute ischaemic heart disease or pulmonary embolism, a medical emergency caused by a blood clot blocking an artery in the lung, or other organ dysfunction related to thrombosis, including acute kidney failure.
“In addition, it has been observed that Covid-19 can significantly deplete blood oxygen levels even though the patient may not initially feel symptoms of respiratory distress, which is known as ‘silent hypoxia’. By the time people seek medical assistance, their condition may already be serious, with a low oxygen concentration recorded.”
Dr Kok says that in addition to Covid-19 testing, which has become standard for all patients being admitted to Netcare hospitals, a D-dimer test, which indicates clotting, must be performed and the blood oxygen level of emergency patients must be monitored.
“Supplemental oxygen and blood thinning medication, as appropriate, can help to restore blood oxygen and counteract the abnormal clotting effect,” she says.
According to Dr Kok, people who already have any kind of heart or blood vessel disease may be at greater risk for not only contracting Covid-19, but also more severe illness.
“People with chronic illnesses or co-morbidities, especially those over the age of 55, should remain in close contact with their doctor.”
Dr Kok advises that people should report any new symptoms that may arise to their doctor, either their general practitioner or relevant treating specialist, promptly.
“From what we know of Covid-19 so far, better outcomes for many health conditions are usually achieved with early treatment,” she concludes.