Post by the Scribe on May 30, 2021 22:21:28 GMT
The Mystery of "COVID Tongue" Explained
Doctor Mike Hansen
671K subscribers
What is the COVID tongue? COVID seems to be causing some people to have an extremely large tongue, called macroglossia.
Macroglossia is relatively rare but not unheard of. Certain chronic conditions can cause it, like amyloidosis. But it can also be caused by different types of angioedema. Angioedema is an area of swelling (edema) of the lower layer of skin and tissue under the skin or mucous membranes.
Mentioned Video:
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There is something called hereditary angioedema that occurs at a younger age. Then there’s something called acquired C1 inhibitor deficiency, usually at an older age. And there is also the well-known ACE inhibitor-induced angioedema. ACE inhibitor medications are most commonly given for patients with high blood pressure.
Over the last year or so, there has been a cluster of these macroglossia cases in Texas. Dr. James Melville has seen 9 of these cases in that timeframe because he gets these patients referred to him to so he can surgically reduce the size of their tongue. I don’t know all the details in these cases, but based on the media report, this is what we know:
In all 9 cases, they were intubated. In 2 cases, they suffered strokes. In the other 7, they were hospitalized with COVID.
Understanding what is going on here helps to better understand a known medical condition called ACEi-induced angioedema. Angiotensin-converting enzyme (ACE) inhibitors are the leading cause of drug-induced angioedema in the United States because they are widely prescribed. Examples of these meds include lisinopril, captopril, ramipril, enalapril, and the like. So basically, if it ends in “pril,” it's an ACE inhibitor.
When angioedema occurs due to these medications, it most commonly causes swelling of the lips, tongue, or face. Hives, meaning urticaria, are notably absent. ACE inhibitor-induced angioedema occurs in 0.1 to 0.7% of those who receive these medications and is five times more likely to occur in African descent.
The swelling usually develops over minutes to hours, peaks, and then resolves over 24 to 72 hours, although complete resolution may take days in some cases. Swelling occurs due to elevated levels of bradykinin, a substance called des-Arg9-BK, and a substance called substance P. These substances cause the blood vessels to dilate, leading to swelling. When the body doesn’t break these down quick enough, you get the swelling.
When someone is taking an ACEI, the risk of this happening is slightly higher. So is it possible that these patients were given an ACEI? Yes, it's possible. Especially the ones who had strokes, because usually stroke patients have elevated blood pressures. But it's also possible that this was covid related.
For the two people who were not covid cases, maybe they had covid, and they didn’t know it. Maybe they had a false negative test because they were tested outside the window for the PCR test. So we just don’t know. But we know that 7 out of the 9 did have COVID.
And COVID binds to ACE2 receptors. And the tongue is lined with ACE2 receptors. And when the virus binds to the receptor, we know that it alters this pathway, affecting bradykinin levels. This is something I talked a lot about in this video…
Why are some people more prone to this? Again, it comes down to genetics. There are various genetic polymorphisms in certain enzymes called aminopeptidase P and neutral endopeptidase, which occur at a greater rate in African Americans. These polymorphisms lead to lower circulating levels of these enzymes responsible for degrading bradykinin and its active metabolite (des-Arg9-BK).
And it makes sense that the SARS-CoV-2 virus triggers this same mechanism. So COVID tongue looks like one more thing to add to the list of strange things that come with the disease. And one more reason to get the vaccine.
Doctor Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine