The coronavirus may cause brain damage in as many as six in 10 critically-ill patients in hospital, a study has suggested.
British researchers looked at 125 people hospitalised with the virus at the height of the UK’s crisis in April – but they admitted the patients were selected by doctors and were likely to be some of the most severely-ill.
Sixty-two per cent suffered a stoke during their hospital stay, while almost a third developed psychosis or dementia-like symptoms.
Scientists from the universities of Liverpool, Southampton, Newcastle and University College London admit their study is too small to draw firm conclusions.
But they say it provides a ‘snapshot’ of the lesser-known neurological damage that the respiratory infection may be triggering.
Up to a third of people who fall severely ill with coronavirus develop dangerous blood clots, which can trigger deadly strokes if they migrate to the brain and cut off its blood supply.
Scientists are struggling to pinpoint exactly why the clots form but they are thought to be caused by severe inflammation caused by Covid-19 infection.
This inflammation in major arteries leading to the brain is thought to be behind the psychiatric problems seen in some patients.
The coronavirus may cause brain damage in as many as six in 10 people, a small study of more than 100 patients has found (file)
The latest study, published in The Lancet Psychiatry, found the most common brain damage was a stroke, which was reported in 77 of 125 patients (62 per cent).
Of these, 57 patients had a stroke caused by a blood clot in the brain, known as an ischaemic stroke and nine patients had a stroke caused by a brain bleed.
One patient had a stroke caused by inflammation in the blood vessels of the brain.
Age data was available for 74 of the patients who experienced a stroke and the majority were over 60 years of age (82 per cent).
WHAT’S CAUSING BLOOD CLOTS IN COVID PATIENTS?
One in three people who fall severely ill with coronavirus develop dangerous blood clots, which scientists believe is contributing to their deaths.
The clots can become fatal if they migrate to major organs, like the lungs, and cut off their blood supply.
The blockages can trigger heart attacks, strokes, organ failure and pulmonary embolism, if they migrate to major organs.
While experts are unsure why the virus causes the blockages, there are three main theories:
The prevailing theory is that it is the result of a an immune overreaction called a ‘cytokine storm’.
Cytokines are chemical-signaling molecules which guide a healthy immune response.
They tell immune cells to attack viral molecules in the body.
But in some people, this resonpse goes into overdrive and immune cells start attacking healthy tissue as well, known as a cytokine storm.
As blood vessels become damaged they can leak, causing blood pressure to drop and driving up the chance of clots forming.
BYPRODUCT OF INFECTION
Other scientists say the surge in strokes may be a byproduct of the way COVID-19 invades the human body.
Professor Ian Jones, a virologist at the University of Reading, told MailOnline: ‘Covid binds to an enzyme called ACE2 which is on the surface of the cell.
‘It simply uses it as a way of attaching itself but in doing so the enzyme function of ACE2 is reduced.
‘The consequence of this is an imbalance of hormones called Angiotensin I and Angiotensin II which together regulate blood pressure.
‘It could be related to the increase in strokes reported.’
VIRUS’ UNIQUE SHAPE
Dr Robert Bonow, a professor of cardiology at Northwestern University, said it may be the coronavirus’ unique shape that is causing the bloodclotting issues.
He said the virus’ spikes, which latch onto receptors in cells, can also attach to blood vessels.
Once they dock onto these blood vessel cells, the viral particles can trigger damage to these as well as to heart muscle, Dr Bonow says.
Meanwhile 39 patients showed signs of confusion or changes in behaviour reflecting an altered mental state.
Nine had unspecified brain dysfunction, known as encephalopathy, and seven patients had inflammation of the brain, medically known as encephalitis.
The remaining 23 patients with an altered mental state were diagnosed with psychiatric conditions.
Only two of these patients had been diagnosed with a mental health problem prior to being hospitalised with Covid-19.
But the researchers say they cannot exclude the possibility that these people were living with undiagnosed conditions beforehand.
The 23 patients with psychiatric diagnoses included ten patients with a new-onset psychosis and six patients with a dementia-like syndrome.
Seven patients had signs of a mood disorder, including depression and anxiety. Age information was available for 37 of the 39 patients with an altered mental state and of those, around half were aged under 60 years of age (49 per cent).
Co-author Dr Benedict Michael, from Liverpool University, said: ‘Whilst an altered mental state was being reported by some clinicians, we were surprised to identify quite so many cases, particularly in younger patients, and by the breadth of clinical syndromes ranging from brain inflammation (encephalitis) through to psychosis and catatonia.
‘Clinicians should be alert to the possibility of patients with Covid-19 developing these complications and, conversely, of the possibility of Covid-19 in patients presenting with acute neurological and psychiatric syndromes.’
But independent scientists say people should ‘not worry too much’ about the findings because they are ‘probably relatively rare’ in most Covid-19 patients.
Michael Sharpe, professor of psychological medicine at the University of Oxford, said: ‘This report describes often striking cases of neurological and psychiatric illness as being sometimes associated with severe Covid-19 in hospitalised patients.
‘It reminds us that Covid-19 is more than a respiratory infection and that we need to consider its link to variety of other illnesses.
‘However, because this is only a series of case reports of patients seen by certain types of hospital specialists, we cannot be certain that these illnesses were in fact caused by Covid-19 or were simply co-occurring.
‘Additionally, we cannot estimate how common these illnesses are in the wider population of people who develop Covid-19. We do need to do research to address these uncertainties.
‘However at present people in the general population should not worry too much about these possibly associated illnesses as they are probably relatively rare in those who become infected with this coronavirus.’
Professor Paul Garner, an infectious diseases expert at the Liverpool School of Tropical Medicine, said: ‘I am concerned that it is too early for confident psychiatric diagnoses in patients with severe Covid-19 who are experiencing symptoms that are used in the diagnosis of long term psychiatric illnesses.
‘My concern is that this [latest study] is a classic case of doctors putting things in boxes.
‘People have symptoms and then doctors diagnose them against pre-existing understanding, but in this case we do not yet understand what is happening with patients with Covid-19, nor do we know the natural course of the Covid-19 neurological, psychological, or psychiatric symptoms.
‘There are many more questions to be answered and studies to be done before we can confidently say if Covid-19 causes psychiatric disorders such as psychosis.’