Transcription
We continue talking about hematology, and we are discussing anemia. Please go ahead and watch the previous video, the introduction to anemia. Okay. Today, specifically, we're talking about microcytic anemia. And as a recap, remember symptoms: tired and pale, headache, and even angina sometimes in people with previous heart problems. Micro means small; cytic cell, small cell; which cell? The red blood cell. Anemia: no amia, blood; so anemia literally means no blood, i.e., less. Our basis, as we have said before, microcytic anemia: when the MCV, mean corpuscular volume, is less than 80. What's the MCV? Go ahead and watch my video on the erythrocyte indices. Okay. Anemia is decreased oxygen-carrying capacity of the blood; decrease the RBC mass; decrease hemoglobin and hematocrit; an RBC count. So we have decreased hemoglobin, hematocrit, and the MCV is less than 80. Perfect.
Okay, why are the cells small in microcytic anemia? To know that, let's take an example of iron deficiency anemia. Okay, so you are deficient in iron. Now, we have said before, when we just got tomato pieces, how the red blood cells are formed through a cascade from the myeloid stem cell, okay, going through all of these steps. When cells go from here to here, they decrease in size. While they are decreasing in size, they are waiting for the iron to come. Okay, so iron, please come. Not coming. I'm deficient in iron, please come. I'm deficient. Not please come. I'm deficient. Not please come. I'm deficient. Not. So we end up with a cell smaller than normal, i.e., microcytic anemia. I'm still waiting for the iron. By the same token, this is actually kind of okay. Why? The RBC's are trying to adapt. How? Because we have, like, this is the hemoglobin; hemoglobin, hemoglobin came alone. The hemoglobin is not enough. Okay, so the cell is decreasing in size in order for the hemoglobin to be relatively occupying a larger space. Okay, it's kind of adaptation as well. So there are two reasons for microcytic anemia: why are the cells small? Small, first: iron is deficient, and I'm waiting for the iron, so the cells are decreasing in size. Number two: when I am decreased in size like this, okay, the hemoglobin will occupy a relatively larger portion of me, okay, and this will try to mitigate the problem.
Now, in order to memorize all of the forms of microcytic anemia, we have to see this diagram or illustration. So we know that hemoglobin, hemoglobin consists of heme and globin; that's why the name is hemoglobin. Okay, heme will be further broken down into iron and protoporphyrin. Okay, what will happen to that globin? Will be recycled. Globin is protein; when ends with "in," it's a protein. The amino acid in this protein will be recycled. The iron, same thing, will be recycled; we'll use it again. Protoporphyrin has a different pathway, which we will discuss later. So causes of microcytic anemia include: what about iron deficiency anemia? It will affect this portion, this step, this part. So here we have iron deficiency anemia. Okay. How about thalassemia? Here, problem: the globin. Thalassemia, perfect. How about sideroblastic anemia? Here: protoporphyrin. Good. Which one was the last one? Yes, anemia of chronic disease. Same thing: iron. Okay. Anemia of chronic disease. What's the difference between iron deficiency and anemia of chronic disease? The first one: I'm deficient in iron. The second one: I have iron, but I cannot use it. We will discuss all of these further in the next video, so please subscribe and stay tuned.