Critically ill COVID-19 patients develop virus-induced damage of respiratory muscles, scientists at Amsterdam UMC in The Netherlands reported in JAMA Internal Medicine.
They performed autopsy studies of the diaphragm, the main respiratory muscle, in 26 COVID-19 patients who died in the intensive care unit (ICU) and 8 ICU patients who died without COVID-19. In everyone, the diaphragm muscle cell membranes contained a protein called ACE2, which the new coronavirus uses as an entryway into cells.
The researchers found genetic evidence of the virus in diaphragm muscle cells in some of those who died from COVID-19, and microscopy analyses showed much more connective tissue scarring (fibrosis) in COVID-19 patients’ diaphragms, indicating damage, study coauthor Coen Ottenheijm told Reuters.
He said the diaphragm damage may help explain why it is often difficult for COVID-19 patients to breathe on their own again after they have been on mechanical ventilators in the ICU. It may also explain the persistent shortness of breath in patients recovering from COVID-19.