Transcription
Alright, medicos. Is perfection Alice listeners? Let's talk about sideroblastic anemia. In the last video, I explained heme synthesis. Please go ahead and watch that video first. This video will make a lot of sense then.
Sideroblastic anemia, again. Anemia symptoms: tired and pale, pale and tired. Sometimes, I have a murmur; sometimes, I can get angina. Also, there is exercise intolerance, extreme fatigue, etc. Sideroblastic anemia is characterized by the presence of ringed sideroblasts in the bone marrow. Let's talk about that, but first, remember hemoglobin: heme and globin. The heme consists of iron and protoporphyrin. Iron deficiency anemia will be here; anemia of chronic disease will be here; thalassemia will be here; sideroblastic anemia will be here. These are the main causes of microcytic anemia. So, the word sideral means iron or constellation, depends on Greek or Latin. Blast means growth. Let's use the three words, although not scientifically accurate, but there is a growth of iron constellation, on constellation iron, around the nucleus of the RBCs. But wait, you have said that RBCs are non-nucleated. But this is a disease; it's an exception because it's a disease. And of course, the sideroblasts are immature, so it makes sense that they are nucleated.
Whatever. Sideroblastic anemia means a defect in protoporphyrin synthesis. Protoporphyrin synthesis is part of heme synthesis, and please go ahead and watch my video on heme synthesis first. So, when protoporphyrin forms, it combines with iron to form heme. Heme combines with globin to form hemoglobin. However, in sideroblastic anemia, there is no protoporphyrin. This iron has nothing to be combined to, so it will accumulate and accumulate and back up and accumulate and will increase. It will give us a picture very close to hemochromatosis or any iron overload condition. I will not be able to form heme; I will not be able to form hemoglobin; hence anemia, because anemia is low hemoglobin, low hematocrit.
What are the causes? Alcoholism. Alcoholism: major cause of sideroblastic anemia. Alcohol is a toxin to the mitochondrion. What else? B6 deficiency. Do you want to know why? I've explained it in my video on heme synthesis. Lead poisoning. Do you want to know why? Go ahead and watch my video on heme synthesis. I know I'm boring. Others: we have congenital type of sideroblastic anemia, mostly X-linked or can be autosomal recessive; acquired reversible, such as this case of B6, vitamin B6 deficiency; acquired clonal, which is part of a syndrome called myelodysplastic syndrome or myelodysplasia. And since it's associated with myelodysplasia, there is an increased risk of leukemia, especially AML. This iron that is accumulating because there is no protoporphyrin will accumulate in the RBC, or RBCs, around the nucleus, forming what's called as ringed sideroblast. The ring is iron, so as said, it's an iron overload condition. So it makes sense that I may have heart disease, liver damage, kidney failure, why? Because iron builds up in organs, and iron is bad. Of course, you know that from the Fenton reaction. Also, I can get hepatosplenomegaly.
Okay, lab results. Any anemia: low hemoglobin, low hematocrit. What about the RBC count? Of course, it will be low; that's a no-brainer. How about MCV? Since it's a microcytic anemia, MCV will be low or maybe normal. Okay, forget about this. Forget about reticulocytes. Okay, white blood cells and platelets, I don't care. Let's go about iron studies. How about serum iron? It's an iron overload condition. High ferritin: furnace iron storage. If serum iron is high, and it can go to be stored, ferritin will be high. How about TIBC? Ferritin is high; automatically TIBC is low; that's a no-brainer. How about percent transferrin saturation? It will be high because saturation is the ratio of serum iron over the TIBC. RDW: oh, this is cool. Can be increased. Why is that? It's similar to iron deficiency with respect to the bone marrow. It makes no difference if you are deficient in iron or if you have iron that you cannot use. Okay, kind of makes sense.
How to diagnose this condition? As we have said before, you have signs and symptoms. You may have hepatosplenomegaly and signs of organ damage because of the iron. So you have the clinical, and then you got the lab: perfect CBC and iron studies. You can do peripheral smear. What will the peripheral smear show? Something called basophilic stippling. Okay, basically stippling, why? Because lead poisoning affects the ribonuclease; the ribonucleic, ribosomes cannot be degraded and they will persist in the RBC. This persistence is the stippling, so that is why we have basophilic stippling. Also, we may get the famous target cells. Okay, what else? You may have something called Pappenheimer bodies, but we don't care. We can do a bone marrow biopsy to get these nice ringed sideroblasts. Ringed sideroblasts. They will not exit the marrow; they are in the marrow. We need a bone marrow biopsy. And since this is iron, we will use which type of stain? Let me know in the comments. That's an easy question. Perfect. So, CBC, iron studies, peripheral smear, bone marrow biopsy: this is the diagnosis.
Treatment: if it's vitamin B6 deficiency, give vitamin B6. If it's severe anemia, we transfuse blood. If it's very severe, we can do bone marrow transplant. Here we go. Question of the day: when is MCV expected to be high in sideroblastic anemia? We have said that it's microcytic, so it's probably low. There is an exception to that, and what's the exception? By the way, I've mentioned the condition, the name of the condition in this video, but I didn't tell you which one. So, when is MCV expected to be high in sideroblastic anemia? Let me know in the comments below. Also, let me know which stain is used to see iron in the rings that are seen on the bone marrow biopsy under microscopy. So that's it. I'll see in the next video. Please consider subscribing to get my previous questions. Go to my Facebook page; there's an album there called Question of the Day. Thank you, and see you in the next video.