If you’ve seen my previous videos on autopsies that were done on COVID-19 patients, it’s pretty clear by now that when patients do die of this coronavirus, it’s because of the lungs. Either because of all the inflammation in the lungs, with pneumonia and cytokine storm and ARDS, sometimes with multiorgan failure….or because of the major blood clot that develops in the lungs. Sometimes though, blood clots show up in other parts of the body as well. For example, in some cases, clots can travel to the brain, and lodge in the blood vessels there, causing decreased blood flow to certain regions of the brain, and this is known as a stroke.
But this virus, in a different manner, can cause neurologic symptoms in some people, such as headache, confusion, and anosmia, meaning loss of taste and smell. But we don’t really know why this coronavirus sometimes causes these symptoms. Is it because the coronavirus travels in the bloodstream to the brain? Maybe. After all, there are ACE2 receptors that are located in the brain. Is it because the virus gets in our nose, and used the olfactory nerves that are there to gain entry into our brain? Or are these symptoms more related to the effects of the cytokine storm, which is actually pretty common with infections in general, whether that be from pneumonia or something else? In a recent study in NEJM, they looked at brain findings from autopsies done on 18 patients who died from COVID-19, in a single teaching hospital. All 18 of these patients had nasopharyngeal swab samples that were positive for SARS-CoV-2 on RT-PCR.
Eleven COVID 19 patients required mechanical ventilation, meaning a breathing tube. Interestingly, it was noted that all of the ventilated patients had a confusional state or decreased arousal from sedation for ventilation. The way that I interpret this is that when they paused the sedation, meaning they temporarily stopped the sedation to assess their mental status, the patient was able to follow commands during that time. This, in general, is not uncommon, but this does seem to occur more often with COVID 19 patients, and this is something that I’ve been finding with my COVID 19 patients in the ICU.
On average, these COVID-19 patients died about 10 days after being admitted to the hospital.
When they did the autopsies, they looked at the brain as a whole, and they also sampled 10 different areas of the brain, and then looked at those samples underneath the microscope. Microscopic examination showed acute hypoxic injury in some regions of the brain. Acute hypoxic injury means tissue was damaged as a result of not getting enough oxygen. There was an acute hypoxic injury in the cerebrum, which is the part of the brain that allows us to think, and be conscious. There was also an acute hypoxic injury in the cerebellum in all the patients. There were no blood clots in the brain, or vasculitis, meaning inflammation of blood vessels. So another thing we want to know, is, is the virus actually invading the cells of the brain? In this study, they actually tested the brain tissue for the virus with RT-PCR.
Dr. Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine
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