Transcription
Greetings. Today's topic is normocytic anemia. We have been talking about anemia since the beginning of history in my playlist called Hematology Oncology. There are like around 30 videos so far, so this is a series; it's supposed to be watched in that order. So, if you can, go ahead and watch the previous videos. But for now, let's talk about normocytic anemia. We have talked about microcytic first, then macrocytic, and the last type is the normocytic anemia: normal, normal-sized RBCs. The MCV is 80 to 100; that's the normal MCV; that's why it's normocytic anemia.
Symptoms of anemia are the exact same: pale, pale, and tired. Sometimes I have angina, and I can also get a murmur, headache, as well as exercise intolerance. And here is your nice slide about hematopoiesis. The myeloid stem cells will give us the RBCs, and they have a lot of steps until they become mature RBCs. Reticulocytes are the baby RBCs. Mr. MCV always determines the type of anemia: microcytic, normocytic, or macrocytic. Normocytic anemia will have the normal MCV, 80 to 100. So what's the difference? Let's say you have like a patient, and you measure the MCV; it's 80 to 100. It can be a normal patient or can be a patient with normocytic anemia. There is a difference between a normal patient and an anemic patient; a huge difference. What's the difference? The normal patient has a normal RBC count, normal hemoglobin, and hematocrit. The normocytic anemia has a decreased RBC count, decreased hemoglobin, decreased hematocrit.
Now let's get into it. So, normocytic anemia: MCV is 80 to 100. So this is the normocytic anemia. Okay, fine. We have three main causes: acute blood loss, underproduction, or over destruction. I've made this word up; "over destruction" is not a real thing. I mean hemolysis, increased destruction. In acute blood loss, as well as underproduction, the reticulocyte index is less than 2.5. What is the reticulocyte index? It is a doubly corrected reticulocyte count. Reticulocyte count needs two corrections, and you can watch my previous video on reticulocytes because it's like a long topic. So, for now, we have acute blood loss and underproduction anemia with a reticulocyte index less than 2.5. However, in hemolysis, the reticulocyte index is more than 2.5. There are a lot of reticulocytes.
Fine, let's go to acute blood loss. It can be external, such as well, knife wounds, car accidents, open fractures; or internal, such as ruptured spleen, ruptured abdominal aortic aneurysm. Fine. And, of course, the acute blood loss will lead to which type of shock? Yes, hypovolemic shock. Hypo-less volume, okay. Fine. First, in acute blood loss, everything will be fine, really. Yes, RBC count, hemoglobin, hematocrit, everything will be fine in the beginning. Then what will happen? Why is everything fine? Because you are losing blood; you're losing RBCs and you're losing plasma. Okay, that's in the beginning. So you're losing both of them at the same rate; that's okay. It's still normocytic. Then what will happen? Let's see. Here is your blood vessel; you are bleeding or losing blood, losing RBCs and plasma at the same rate, so normocytic anemia. Then plasma is replaced from the interstitial, going to the blood vessel, so it will dilute your RBC count. So if you measure your RBC count, you will have less RBCs, less hemoglobin, and hematocrit. That's later; earlier you have normocytic, you have normal, but later you have normocytic anemia. So earlier you are normal; later, when plasma is replaced from the interstitial, so we have more plasma than RBCs, this is normocytic anemia. You will have decreased RBC count, decreased hemoglobin, and decreased hematocrit. I hope this one is clear. So there is a problem when giving normal saline to a patient who is bleeding. Why is that? Because the patient is bleeding RBCs and plasma. Normal saline is kind of plasma, very similar. So you're giving plasma instead of giving both plasma and RBCs. Wow. So this is a problem. Yes, this is a problem. Be aware of that. You will have an RBC deficit appearing, why? Because saline is acting like plasma. That's why nowadays we have something called packed red cell. Packed red cells are like bags, okay, of not blood, but only the red blood cells. One unit of packed red cells should increase your hemoglobin by one and increase your hematocrit by three. That's a packed red cell. Okay, fine. We are done with this. Yeah, until now, reticulocytes are low. The bone marrow starts to realize, wow, I need to produce more, so it produces more reticulocytes, but this will take around one week, maybe five to seven days, but it will take a lot of time. In the beginning, the reticulocyte index is less than 2.5.
Okay, good. How about underproduction? This will include iron deficiency anemia or anemia of chronic disease. Early, the bone is still having enough iron, but later it will be microcytic because the bone marrow ran out of iron. How about aplastic anemia? The bone marrow is useless; you get anemia, leukopenia, and thrombocytopenia, i.e., pancytopenia. Chronic renal failure? Why? Because of less EPO secreted, as well as anemia of chronic disease. There is a relation between chronic renal failure and anemia of chronic disease. You have to watch my previous video on anemia of chronic disease. Also malignancy, by a different mechanism. Okay, fine. Over destruction or hemolysis: reticulocyte index is more than 2.5, sometimes more than 3. Intrinsic versus extrinsic. Intrinsic means the problem isn't in the blood vessel; it could be in the hemoglobin, such as sickle cell disease. We have hemoglobin S, membrane defect spherocytosis, or enzyme deficiency, such as pyruvate kinase deficiency or glucose-6-phosphate dehydrogenase deficiency. How about extrinsic? Yeah, a valve, like a stenotic aortic valve. Okay, and the RBCs, while passing, gets smashed and sheared, producing schistocytes. This is called microangiopathic hemolytic anemia. How about a complement problem or antibodies attacking these nice cute RBCs? All of these are the causes of normocytic anemia. We will discuss them one by one in detail in the upcoming videos, but for now, thank you for watching. Please get the main idea: other than acute blood loss, normocytic anemia is either due to underproduction or over destruction, and this will be the discussion later. I'll see you in the next video. Take care. Study hard. Be well.