Some patients with long Covid-19 symptoms could be suffering from a rare disorder that affects the nervous system, scientists now believe.
Postural orthostatic tachycardia syndrome (Pots) can cause dizziness, extreme fatigue and a rocketing heart rate.
Much remains unknown about Pots but doctors can treat it and the discovery sheds more light on the long-term implications of coronavirus.
Female Covid patients aged between 15 and 50 appear to be worst affected.
Doctors told The National that Pots has not been formally diagnosed in many recovering Covid-19 patients in the UAE, but most recognised the symptoms.
Dr Elhadi Abbas, a senior consultant and head of internal medicine at RAK Hospital, spent two weeks in the intensive care unit after contracting the virus on September 3.
While he has made a full recovery, Dr Abbas, 70, said others remain blighted by long lasting symptoms that could be explained by the under-reported syndrome.
“Pots generally follows infections in patients who have been in hospital for some time,” said Dr Abbas, from Sudan.
“I have seen Covid patients who have reported similar symptoms of fatigue and dizziness, so I would not be at all surprised that they will have undiagnosed Pots.”
Symptoms can be debilitating, and include dramatically elevated heart rates from small movements, dizziness and extreme fatigue after even minor physical exertion.
“As a syndrome, it may be unrecognised but as a symptom seen in recovering patients, it is very common,” said Dr Abbas.
He said viral infections generally cause increased heart beats, dizziness and fatigue, which are considered part of the recovery.
“Some people can fall over, and we usually see this in patients in hospital with any viral infection.
“Older people are, of course, more at risk from fractures and other trauma as a result.”
While the diagnosis of Pots is relatively common in the US, with as many as three million recorded cases, its association with recovering Covid-19 patients is less conclusive.
Brain fog, nausea, blurred vision and palpitations have also been reported in patients with the condition.
It is diagnosed using a 10-minute standing test to see if symptoms appear, or a head-up tilt table test if the patient is bedridden.
Treatment involves adding sodium and extra fluid to the diet, or beta-blockers to control the heart rate.
Leg stockings can also help increase blood flow to the heart, to reduce the effects of dizziness.
“I needed oxygen and was in ICU for two weeks,” said Dr Abbas, of his own recovery.
“Covid is an experience you would not wish on anyone. The psychological effect is as damaging, as we know so little about it.”
He said the virus had symptoms that could continue for a long time but people usually recovered quickly.
“Those with severe symptoms seem to suffer for a long time, they lose weight and get tired and short of breath easily. That could continue for four months or so,” he said.
In August, RAK Hospital was one of the first to launch a free Covid-19 rehabilitation programme.
Nurses developed specialist rehabilitation programmes for recovering coronavirus patients.
Many patients who spent time in hospital reported difficulty readjusting to everyday life, with even basic tasks such as washing, dressing and walking becoming a challenge.
Long-Covid has become a familiar diagnosis, with a fifth of people in the UK reporting continuing symptoms, five weeks after recovery.
Danny Altmann, an immunology professor at Imperial College London, said the figures were worrying and could indicate as many as 10 million people in the UK have a long-term health condition with no current explanation or treatment plan.
Dr Nezar Bahabri, an infectious diseases consultant at Dr Soliman Fakeeh Hospital in Jeddah, tested positive for the virus six months ago.
The 49-year-old treated hundreds of patients during the pandemic, and continues to suffer from symptoms, including breathlessness and dizzy spells.
“I have some kind of lung fibrosis too,” he said.
“No one knows if it can be treated effectively, but more than likely the damage is irreversible.”
Dr Bahabri also reported tachycardia, the rocketing heart rate seen in those with a Pots diagnosis.
“Whenever I move, I have a very fast heart rate,” he said.
“I am taking medication for that, but I am also losing my hair. The other doctors I have spoken with said this is common.
“While I am back at work, it is difficult.
“It is likely I have Pots, but there is not much more that I can do.”
The condition is estimated to affect only 1 per cent of the world's population, according to a 2018 study published in the Journal of Internal Medicine.
John Hopkins University in Baltimore, America, runs a Pots clinic dedicated to treating an increasing number of recovering coronavirus patients.
Its director, Dr Tae Chung told The National the condition was also likely to become more prevalent in the UAE.
“It is not clear at this point, but I personally think that Pots after Covid-19 can develop into an issue in the UAE as well,” he said.
“We see patients from almost all ethnic backgrounds in our clinic.
“Unfortunately, no one knows about the long-term impact of the condition.
“It is believed to be non-fatal, but Pots can be significantly debilitating for some patients.”
Dr Chung said it remains unclear if the syndrome results in permanent damage to a patient’s heart or nervous system.
A reason for under reporting could be that symptoms need to be present for about six months before a diagnosis is made.
“Given that the pandemic started early this year, we only began to see Pots after [diagnosing] Covid-19 infections,” Dr Chung said.
“We will need more research to better understand Pots after infection and its long-term impact.”