Transcription
Hello, one more time. Let's compare between intravascular hemolysis and extravascular. For analysis, we have discussed them separately in the previous video. Today, it's a comparison. Again, there is your erythropoiesis. Here are the RBCs. Mean corpuscular volume determines if the anemia is microcytic, normocytic, or macrocytic. Here is your normal, CEREC anemia, acute blood loss, underproduction, or overdestruction, or hemolysis. Reticulocyte index is more than 2.5 on either. Is reticulocyte doses from the cause standpoint? Is it either intrinsic or extrinsic? So, causes: intrinsic or extrinsic mechanisms; intravascular or extravascular. There are other classifications, such as inherited vs. acquired, acute versus chronic, etc. So, mechanisms of hemolysis are intravascular, extravascular. Discussed in the previous video, in brief: extravascular—this spleen or any reticuloendothelial organ is destroying your red blood cells. In intravascular hemolysis, the hemolysis is occurring inside of the blood vessel due to, maybe, complement enzyme deficiency, macroangiopathic hemolytic anemia, or microangiopathic hemolytic anemia. The song: sing with me: DIC, TTP, HUS—help me! Microangiopathic hemolytic anemia. Here is the process of your extravascular hemolysis. Please go to my video on extravascular hemolysis to get some details. And here is the intravascular hemolysis. Again, for details, watch my video on intravascular hemolysis. What's unique here is hemoglobinuria and hemosiderinuria. Both of them are excreted in the urine.
Now, let's talk clinically. What's the difference between intravascular or extravascular? Usually, they are the same, really. Yep, all signs, symptom, and symptoms of anemia. They are tired, and extreme fatigue, dizziness, shortness of breath, dyspnea on exertion, also exercise intolerance. Signs will include stuff like murmur, pale conjunctiva, etc. But here also, jaundice. Which type of jaundice? Uncomplicated hyperbilirubinemia, a hemolytic jaundice, a pre-hepatic jaundice, and of course, unconjugated bilirubin. There is hemolytic jaundice. You'll have urine discoloration, also known as Coca-Cola-like urine. Splenomegaly? Yes, both intravascular and extravascular can have splenomegaly, especially the extravascular. That's fine. Why will intravascular have splenomegaly? Oh, extramedullary hematopoiesis. When the bone marrow realizes that, oh, I'm getting overwhelmed, I have a lot of stuff to do, let's call our friends, the extramedullary organs, to try to produce some red blood cells. Hepatomegaly? Yep. Skeletal changes? Yes, from the extramedullary hematopoiesis, the same as thalassemia, of course. Tell us, you'll be more severe in the skeletal changes. By the way, why hepatomegaly? Because the liver is working really hard to conjugate this excess of unconjugated bilirubin.
Okay, how to read labs? If the haptoglobin is low, there is hemolysis. Boom, just like that. Haptoglobin low, hemolysis, especially with the intravascular. Haptoglobin is really low. Maybe extravascular is not that obvious. How about increased unconjugated bilirubin? Both of them, especially the extravascular. How about increased LDH? Both increase. Your own hemoglobin and hemosiderin? This is uniquely intravascular. It happens in the blood vessel. Hemoglobin escapes from the blood to the kidney, gets excreted, and the iron in the hemoglobin, hemosiderin. It's uniquely intravascular. Splenomegaly? Both, especially the extravascular. Okay, labs, are you ready? Yep. How about hemoglobin? Normal or low. Hematocrit? Normal, although it's anemia. MCV can be normal, yes, or can be high. Why? You shouldn't say normocytic anemia. Yeah, but remember, when the bone marrow is in a hurry, it secretes larger cells. It does not have any time. Immature cells are larger, so you will have increased MCV. How about MCH? Can be increased for the exact same reason. Cells are more immature. Reticulocytes? Increase, of course, both the reticulocyte count and reticulocyte index. Bilirubin increased? Usually the unconjugated bilirubin. LDH high. Haptoglobin low. Your polychromasia increase? Why? The liver is working very hard to secrete or to conjugate the unconjugated bilirubin into conjugated bilirubin. But of course, the rise in the unconjugated bilirubin will be much, much, much higher than the urobilinogen or the conjugated bilirubin. Bone marrow biopsy will reveal erythroid hyperplasia, but bone marrow biopsy is not necessary to diagnose hemolytic anemia.
Okay, so intravascular and extravascular are similar in a lot of ways. What's different and unique? Splenomegaly, usually extravascular. Unconjugated bilirubin usually goes more with extravascular. Okay, but what's really unique is the hemoglobinuria and the hemosiderinuria. It's uniquely intravascular. If you find them, it's intravascular, boom, and you're done. I'll see in the next video. We'll discuss the different causes and conditions of normocytic anemia. I'll see you then.