COVID-19 Linked To Development Of Myasthenia Gravis
COVID-19 is a disease caused by infection with a novel coronavirus, called SARS-CoV-2. The most common symptoms of COVID-19 are fever, muscle aches, fatigue, congestion or runny nose, cough, breathing problems, and loss of smell and taste. However, there is also evidence that COVID-19 may be linked to the development of neurological conditions after infection, including myasthenia gravis (MG).
Doctors have reported a few rare cases of MG developing among the 52 million people who have been infected with COVID-19 so far. We do not yet know exactly how COVID-19 is linked to MG and other long-term neurological conditions. Doctors should be aware that MG and other neurological complications may occur because of COVID-19.
COVID-19 and MG
We already know that infections can trigger a myasthenic crisis in people who already have MG. A myasthenic crisis is a complication where breathing muscles quickly get weaker. This often requires emergency breathing support in the hospital.1-4
We do not yet know how or why COVID-19 may cause MG to develop in these rare cases. Some doctors have also reported that COVID-19 triggered a myasthenic crisis in someone who already had MG. COVID-19 has caused several long-term neurological complications in some people.3-7
Doctors reported 3 people in Italy who developed MG symptoms 5 to 7 days after developing a fever from COVID-19. Their symptoms included double vision (diplopia), muscle fatigue, and swallowing problems (dysphagia). None of these people had any previous neurological or autoimmune conditions.3,4
They also showed increased levels of the acetylcholine receptor (AChR) antibody. This is one of the proteins that drive the immune system to attack the areas between nerves and muscles. These attacks cause the symptoms of MG. All 3 people’s symptoms improved after they were given typical treatments for MG, such as pyridostigmine bromide.3,4
Doctors reported another case of a person developing ocular MG after a COVID-19 infection. The person showed eyelid drooping (ptosis), high AChR antibody levels, and abnormal muscle-nerve communication. Typical treatments for COVID-19 and MG eventually reduced the person’s symptoms.5,6
It is possible that there are more cases of MG linked to having COVID-19. Fatigue is a common complication of COVID-19, and doctors may miss MG if it develops during or after a COVID-19 infection. However, it could also be that these people would have developed MG anyway. It is still too soon to tell.3
Infections may be a trigger
These reports are consistent with evidence of other infections triggering autoimmune conditions. They are also consistent with evidence of other neurological and autoimmune conditions developing after COVID-19 infection.3,5
If COVID-19 can cause MG to develop, doctors have several theories of how this might happen. For example, the immune system develops antibodies to fight COVID-19. One possible explanation is that these COVID-19 antibodies accidentally begin to target healthy tissue along with the COVID-19 virus.3,5,8
Another possibility is that MG is “unmasked” by an infectious disease like COVID-19. This could happen when a person with mild, undiagnosed MG begins to create enough antibodies that more noticeable MG symptoms begin to appear after a COVID-19 infection.3,5
It is important to keep in mind that we cannot make any conclusions from only a few case reports. We need larger clinical studies to fully understand the possible connection between COVID-19 and MG. Until then, it is important for doctors to recognize that COVID-19 may cause a host of long-term neurological conditions. Quickly diagnosing MG can improve treatment and reduce complications.
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