It was widely believed COVID-19 mostly affects the lungs and airways.
But it’s now becoming clear that it can affect other parts of the body too, such as the brain.
This helps to explain why the range of symptoms extend beyond a new, continuous cough or high temperature – typical warning signs of respiratory infections.
Indeed, data from the COVID Symptom Study app, which has analysed data on more than four million participants, shows that patients with coronavirus frequently suffer from delirium – a state of acute confusion, and disorientation.
To investigate the prevalence of the symptom, Dr Steves and her team included a simple question in our COVID Symptom Study app: “Do you have confusion, disorientation, or drowsiness?”
“We found that it is quite a common symptom, especially in frailer older people. Delirium is more common in those that tested positive than those that tested negative for COVID-19,” said Dr Steves.
The app also revealed that if you have delirium, you are more likely to be admitted to hospital with COVID-19, and you are more likely to need respiratory support, she noted.
Other studies have also found that 20 percent of people admitted to hospital and 60 percent of patients in intensive care with COVID-19 suffered from confusion.
Why are people with COVID-19 suffering from delirium?
Dr Steves suspects that the SARS-COV-2 virus, which causes COVID-19, may enter nerve cells in the brain, disrupting them and causing delirium symptoms.
This idea that coronavirus might attack nerve cells is supported by studies suggesting that loss of smell (anosmia) experienced by some people with COVID-19 is also caused by the virus entering olfactory nerve cells in the back of the nose.
Delirium has also been linked to hypoxia, which is when your body is not getting enough oxygen, which can be related to the lung damage and blood clots caused by the virus.
But clinicians have noticed that patients with coronavirus may not show any signs they are hypoxic.
What should I do if I recognise this symptom?
The NHS does not explicitly state what to do if you experience delirium, but it does say to call 999 for an ambulance if you or someone you care for become confused or very drowsy.
Other emergency indicators include if you:
- Are struggling to breathe
- Are coughing up blood
- Have blue lips or a blue face
- Feel cold and sweaty, with pale or blotchy skin
- Have a rash that does not fade when you roll a glass over it
- Collapse or faint
- Have stopped urinating or are urinating much less than usual
If you have only mild symptoms, such as a new, continuous cough, you should stay at home and self-isolate, the health body advises.
This helps stop the virus spreading to other people.