Opera singer among those hit by COVID-19 blood clot mystery
When Australian opera singer Helena Dix was rushed to hospital with COVID-19 complications late last month, doctors told her she was famous.
“Not for my high notes, unfortunately – it was for the size of the blood clot in my lungs,” she said. “They said it was one of the biggest they had ever seen. They couldn’t believe I was still breathing.”
Australian opera singer Helena Dix, performing in Norma for Melbourne Opera last year (left), and in a British hospital (right) after developing a large blood clot in her lungs .
But Dix had been training for just such an emergency all her life without realising it - performing all around the world as a soprano.
“Singers are the Olympic athletes of breathing,” said Dix, who is now recovering at her home in Britain. “What was so terrifying about this was I had to use all my exercises, everything I knew about breath, and it still ... took it away.”
As scientists race to understand the virus never before seen in humans, Dix is among a small but concerning number of otherwise healthy COVID-19 patients to develop blood clot complications. In New York City, Australian neurologist Thomas Oxley and his colleagues have just published clinical data on a spike in younger patients having strokes – all of them COVID-19 positive.
One woman, 33 and healthy, developed all the usual COVID-19 markers – cough, headache and chills. After a week, her left arm went numb, and then her leg.
She put off going to hospital for more than a day, afraid of what would await her in an emergency department pushed to the limit under the pandemic. On scans, along with the tell-tale “ground glass” mist of COVID-19 on her lungs, there was another spot higher up, deep in the brain - a large-vessel clot blocking an artery. She had had a stroke.
In the brain of another 44-year-old, a new clot started to form even as Dr Oxley operated to remove the first, and smaller "mini-clots" have also been observed in COVID-19 patients elsewhere overseas, possibly even in their toes, he said.
Infectious disease physician Sanjaya Senanayake said clotting was now one of the main mysteries facing doctors treating COVID-19, though the cases were still low and mostly among severe patients. In Australia, where total infections are relatively few, health authorities say they are yet to see patients suffering from strokes or clotting.
"There does seem to be an association with COVID-19," Associate Professor Senanayake said. 'We don't know why yet. It's probably a disruption to the clotting mechanism of the blood vessels caused by inflammation ... when the body's immune response kicks in.”
Helena Dix used singing in hospital to help test her breathing.
That same, overzealous immune response is often responsible for much of the damage caused by a new pathogen – as the body's war on the virus claims healthy cells in the fallout. The other two dangerous coronaviruses to emerge in the modern era, SARS and MERS, also led to some clotting and stroke, though there was “not a strong association”, Associate Professor Senanayake said.
This virus uses the same ACE2 receptor to hack into human cells as SARS, and it is thought to be even better at it, making it more infectious.
"ACE2 is found a lot in the lungs, which is why [COVID-19] gives people pneumonia," Dr Oxley said. "But if you follow ACE2 around the body, it explains why the virus is attacking other [organs such as] the heart. ACE2 is also found on the walls of blood vessels, so our working theory is that it attacks the vessels and starts an inflammation cascade."
Clotting could also be behind growing reports of heart failure in some COVID-19 patients. But Associate Professor Senanayake said the phenomenon could be caused by the virus infecting the heart or something “non-COVID-specific” altogether, more in line with what you would expect from an intense infection leaving the body spiralling into sepsis.
Australia’s Deputy Chief Medical Officer, Nick Coatsworth, said clots could form in the legs and travel to the lungs in those unwell with sepsis [or] in intensive care for a long period. The cause of COVID-19 clotting was still unclear, he said, but Australia was watching cases overseas closely to guide treatment.
Associate Professor Senanayake said advice to consider blood thinners in COVID-19 treatment had already been put out to doctors internationally. At Dr Oxley's hospital, Mount Sinai, internal guidelines had been updated overnight, instructing staff to put all COVID-19 patients entering intensive care on powerful blood thinners.
"This is not like anything we've seen before," Dr Oxley said. "We're also worried people are missing the early signs of stroke because they are afraid to go to hospital."
For Dix, in hospital isolation this month with a monster clot slowly breaking up in her lungs, it hurt to breathe, but she found herself still snatching moments to sing – even fielding requests from a patient next door.
“Every day I practised my breathing exercises, to help test how I was doing," she said. "People think they'll be fine because they're young and healthy. None of us are immune.
"[My voice] still isn't [healed] but I'm so lucky to be here. I know it will come back."