Suddenly feeling confused and delirious is a common symptom of Covid-19 among frail older people, scientists have found.
Officials in the UK don’t recognise any symptoms other than coughing, fever and a lost sense of taste or smell, but there are many others that people suffer regularly.
Experts who run the Covid Symptom Tracker app, from King’s College London, have now found that large proportions of elderly people get delirious when they’re ill.
Delirium is a state that comes on suddenly in which people get confused, struggle to think clearly and may hallucinate, become agitated or have mood swings.
The condition is caused by problems in the brain and can make people more likely to get seriously ill or die in hospital because their bodies become generally weaker and less able to recover, and the effects on the brain can be long-lasting or permanent.
Using self-reported symptoms from around 850 over-65s, the King’s researchers found people official considered ‘frail’ were three times as likely to become delirious.
And of over-65s who ended up in hospital because of Covid-19, one in five (18.9 per cent) said delirium was their only symptom.
The researchers said the coronavirus may be able to get into the brain and infect it, affecting someone’s mental state. And delirium can also be caused by high levels of white blood cells in the brain or by fever, a separate symptom of Covid-19.
Frail people – the elderly and those with long-term illnesses – are the most likely to die of Covid-19 if they catch it, so understanding how it affects them is critical, scientists say (Pictured: An elderly woman with Covid-19 in Italy in April)
This graphic, based on a study by Public Health England, shows which symptoms are most common among people with Covid-19 and how they compare to signs of cold and flu
Dr Rose Penfold, an epidemiologist at King’s, said: ‘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.
‘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.’
Although delirium can cause similar symptoms to dementia or simply age-related brain decline, it usually comes on quickly and makes a noticeable difference.
It may happen in people who are otherwise mentally healthy, or worsen problems in people who already have them.
The team looked at data from 322 older people who were admitted to hospital with coronavirus between March and May, and also at 535 people who tested positive and used the Covid Symptom Tracker app during the same time period.
App users are able to report the symptoms of a friend or family member, meaning the delirious people did not have to report for themselves in every case.
As well as considering the symptoms the over-65s reported – or had reported for them – the scientists looked at how frail they were.
This was done using a questionnaire for the app users or came from a standardised rating made by a doctor for patients who were in hospital.
People considered to be frail may be those who are physically weak, disabled, in poor health, or have brain damage such as that caused by dementia.
Most people living in care homes are considered frail, and they are also the group most at risk of dying if they catch coronavirus, which makes understanding the most common symptoms in that group important.
Frail people with Covid-19 were more likely to have delirium, tiredness and breathlessness than those who were the same age but stronger, the study found.
A third of people who reported having delirium on the app said they did not have the classic Covid-19 symptoms of coughing and fever.
Among the frail patients, 38 per cent had delirium, compared to just 12 per cent of the non-frail patients in the same age group, meaning it was three times more common.
The study found there were no significant differences in the rates of other common symptoms such as coughs or fevers between frail and non-frail groups.
Dr Claire Steves, a geriatrician in London and a lecturer at King’s College, said: ‘The past six months have shown us that Covid-19 can spread catastrophically through care homes.
‘Knowing that delirium is a symptom in frail, elderly people will help families and carers spot the signs earlier of Covid-19 and act appropriately and put in place infection control measures such as isolation, increased hygiene and personal protective equipment to protect this highly vulnerable group.’
The study, published in the journal Age and Ageing, adds to emerging evidence that the symptoms people experience when they catch coronavirus vary by age.
While middle-aged and older people – the group most likely to be admitted to hospital – often have the tell-tale cough or fever, others have them less often.
Young adults appear to often have no symptoms at all or to have just a mild flu-like illness.
And a study done in Northern Ireland found that children often have no symptoms, but among those that do, vomiting, diarrhoea and stomach pain were some of the most common.
They said that coughs were much less common in children with the illness and that problems with the gut were a stronger indicator of whether they had coronavirus.
Dr Tom Waterfield at Queen’s University Belfast told the BBC: ‘We are finding that diarrhoea and vomiting is a symptom reported by some children and I think adding it to the list of known symptoms is worth considering.’
Dr Waterfield and colleagues studied 992 children, of whom 68 had coronavirus. They had an average age of 10 years old.
Counting gastrointestinal symptoms – those affecting the stomach and bowels – would have significantly improved how many of the children could be diagnosed.
