People know that red blood cells carry oxygen. They know that white blood cells fight infection. Many are not aware of platelets. These are other blood cells. They assist with blood clotting.
In 2015 I had a problem with my platelets. I wrote several articles about them at that time.
Normally we have between 240,000 to 450,000 platelets per cubic centimeter of blood. Mine dropped to 2,000. Fortunately, I got better and have had normal platelet counts since that time.
Platelets are formed by giant cells called megakaryocytes. The prefix “mega” suggests their size. Of course they are still microscopic in nature. They are just large compared to other blood cells.
One of the clinical observations in COVID-19 infections is that there are large numbers of megakaryocytes present. That would suggest an increased amount of platelet formation.
Too low a number of platelets causes increased bleeding because of decreased clotting. However, too high a number of platelets can cause increased blood clotting.
Recently, autopsy studies of COVID-19 patients have been released. Their findings are consistent with this. They found an increased number of megakaryocytes present.
They also found an increased number of blood clots in the various organs of the body. The various organs affected included the lungs, kidneys, liver and heart.
Many of the clots were small in size. That means the areas affected were only small. Some were larger.
We already knew about the larger blood clots. They occurred with increased frequency in COVID-19 patients.
The most famous instance was in Broadway performer Nick Cordero.
He lost a leg before he ultimately died from the virus.
What we also know is that COVID-19 produces neurologic symptoms.
A study looked at 125 COVID-19 patients with neurologic symptoms. Thirty-nine of them had outright strokes from the infection.
The rest showed a variety of symptoms. Some showed evidence of dementia. Some showed acute psychosis. What was clear was that there was no predictability to the symptoms.
The initial thought was that these changes were due to infection (encephalitis) or inflammation (encephalopathy). However, the autopsy findings did not show the presence of any virus or any inflammation.
What they showed was that COVID-19 patients who died has multiple small blood clots in brain blood vessels.
Thus, the neurologic symptoms appear to be related to the area of the brain affected by the blood clots.
That is likely why the symptoms vary so much from patient to patient. It is also likely that future treatments may include some kind of anti-clotting medication.
We often take for granted that our blood cells work the way they are supposed to work. That is not always the case. COVID-19 may be the latest example of that kind of failure.