Majority of coronavirus patients who died had muscle inflammation – sometimes very severe – a new study suggests.
Researchers performed autopsies on 43 patients who passed away with a confirmed diagnosis of COVID-19.
Of that group, they found that six in 10 had weakness, swelling and redness of their skeletal muscle tissue – and it was much more evident in patients who were chronically ill.
The team, from the Charite-Universitatsmedizin in Berlin, Germany, says this inflammation is very different from that seen in organs such as lungs, heart and kidneys, and could explain why people with muscle injuries are more likely to die from COVID-19 and why survivors have long-term weakness.
Previous studies have found that COVID-19 patients with skeletal muscle injuries were more likely to have serious illnesses and/or death.
Additionally, as many as two-thirds of survivors of COVID-19 experience fatigue or muscle weakness, or muscle pain.
While it is well-known the damage that the virus causes to the major organs, few muscle biopsies have been performed to assess their damage.
For the study, published in JAMA Network Open, the team looked at 54 patients who died between March 2020 and February 2021.
Among the deceased patients, 43 had tested positive for COVID-19 and 11 were diagnosed with other diseases.
Autopsies were performed on all the patients and, during that process, skeletal muscle tissue samples were analysed.
Muscles looked at included quadriceps, a large muscle at the front of the thigh, and deltoid muscles, a large, triangular muscle that spans the upper arm and the shoulder.
Results showed that 60 per cent of the coronavirus patients had died with muscle inflammation.
This was determined by the presence of MHC class I antigens, which are molecules that alert the immune system to cells that have been infected with a virus.
Next, the team compared the coronavirus patients to the non-virus patients.
On a scale of zero to four, the control patients had an average inflammation score of one while the COVID-19 patients had an average score of 3.5.
What’s more, there was greater evidence of muscle inflammation than heart inflammation suggesting that myocarditis is a rare complication.
“In this case-control study of patients who had died with and without COVID-19, most individuals with severe COVID-19 showed signs of myositis ranging from mild to severe,” the authors wrote.
“Inflammation of skeletal muscles was associated with the duration of illness and was more pronounced than cardiac inflammation
“This suggests that SARS-CoV-2 may be associated with a post-infectious, immune-mediated myopathy.”
– Mail Online