Many survivors of COVID-19, particularly those who were hospitalized with severe disease, experience long-term symptoms even after being discharged from hospital.
Perhaps the most common problem is a persistent shortness of breath and fatigue.
You might think that is because of lung damage due to the coronavirus — and that certainly does occur — but a new study has found that damage to the diaphragm could also be a major cause of those long-term symptoms.
A study of COVID-19 survivors undergoing rehabilitation therapy at the Shirley Ryan AbilityLab has found that damage to the diaphragm — the muscle that draws air into the lungs — could be a significant factor.
“In our COVID Care Unit at Shirley Ryan AbilityLab, we have observed severe muscle limb weakness and functional limitations, including fatigue and shortness of breath, among patients undergoing inpatient rehabilitation,” said Dr. Colin Franz, a physician-scientist at the AbilityLab and an assistant professor at Northwestern University’s Feinberg School of Medicine.
“In the medical community, there is an assumption that shortness of breath is the result of lung damage following COVID pneumonia,” Franz said. “However, based on our previous research, we hypothesized that diaphragm weakness may in fact be a large contributor, and that the diaphragm is negatively affected following severe COVID just as other muscles in the body are.”
Researchers found that in a cohort of 25 COVID-19 survivors admitted to Shirley Ryan AbilityLab for inpatient rehabilitation, 80% showed some kind of abnormality in their diaphragms after ultrasound examination. Three-quarters of the patients experienced impairments related to the diaphragm’s ability to contract and inflate the lungs, and 20% had experienced diaphragm muscle atrophy.
While many patients who have extended stays in intensive care experience muscle atrophy, the new study suggests that this is especially severe for COVID-19 patients.
“Our findings suggest that COVID is uniquely damaging to muscle tissues, including the diaphragm,” said Franz.
“Survivors who are experiencing persistent difficult or labored breathing, fatigue, poor sleep, brain fog or other concerning symptoms should consult with their physicians,” said Dr. Ellen Farr, who conducted the research while a medical resident at Shirley Ryan AbilityLab and Northwestern University. “Additionally, patients who wake up frequently through the night or who experience headaches in the morning should do the same, as it’s possible they’re not getting enough oxygenation when they lie flat, another telltale sign of diaphragm weakness.”
“The diaphragm plays a key role in preserving stamina and is even important for ensuring a good night’s sleep,” said Dr. Lisa Wolfe, co-author of the study and professor of Medicine and Neurology at Northwestern University’s Feinberg School of Medicine, and medical director of Respiratory Care at Shirley Ryan AbilityLab.
The most common problem researchers found when using ultrasound to image the diaphragm was “the impaired quality of the muscle contraction,” said Franz. “Very rarely did they have severe atrophy or wasting of the muscle but what we saw a lot of times was that it wasn’t moving.”
While that may sound bad, for researchers it was actually encouraging.
“We know that this tends to be a pattern that responds better to rehabilitation and exercises training because we don’t have to rebuild the muscle, but we do need to strengthen it,” said Franz. “I would say that a lot of patients have experienced a substantial improvement within three months of being discharged.”