Doctors and carers should look out for signs of confusion or strange behaviour in frail older people because it could be an early warning sign of Covid-19, research suggests.
Even if they have no cough or fever, delirium is more common in vulnerable over-65s than other, fitter people of the same age.
But it’s not yet clear why this extreme confusion or delirium happens.
The study calls for more awareness of it in hospitals and care homes.
The three main symptoms of a Covid infection are a new and continuous cough, a temperature above 37.8C and a change in smell or taste. About 85% of people will have at least one of those symptoms.
However, research suggests certain age groups may also have other symptoms, such as diarrhoea and vomiting in children.
In this King’s College London study, data from more than 800 people over the age of 65 was analysed.
They included 322 patients in hospital with Covid-19, and 535 people using the Covid Symptom Study app to record their symptoms or log health reports on behalf of friends and family.
All had received a positive test result.
The researchers found that older adults admitted to hospital who were classified as frail were more likely to have had delirium as one of their symptoms, compared with people of the same age who weren’t frail.
Frailty is used by doctors to describe older people who find it difficult to recover from everyday illness, strains and accidents. They are also more likely to have falls and end up in hospital when ill.
For one in five patients in hospital with Covid, delirium was their only symptom.
‘Changes in mental state’
Among over-65s using the app, delirium was also more common in frailer people with Covid-19 compared with more robust people of the same age with the infection.
For them, possible delirium was defined as having any symptoms of confusion, disorientation or drowsiness.
Tiredness and breathlessness were also common among frail app users.
And a third of app users who said they had experienced delirium did not have the classic symptoms of a cough or fever.
“Older, frailer people are at greater risk from Covid-19 than those who are fitter, and our results show that delirium is a key symptom in this group,” said Dr Rose Penfold from King’s College London.
“Doctors and carers should watch out for any changes in mental state in elderly people, such as confusion or strange behaviour, and be alert to the fact that this could be an early sign of coronavirus infection.”
The study also highlights the importance of protecting people in care homes, where the virus can spread quickly, by making sure that handwashing, hygiene and PPE (personal protective equipment) are a priority.