Transcription
Hey everybody, let's talk about iron deficiency anemia. So, in previous videos, we have talked about anemia, what's anemia, also microcytic anemia, iron studies. So, if you need anything from previous subjects, please go ahead and watch previous videos first, so this one can make sense.
Let's talk about iron deficiency anemia: tired and pale, pale and tired. Some quick facts are about iron deficiency anemia: it's the most common cause of anemia worldwide. In the developing world, it's usually nutritional, like nutritional deficiency. In the developed world, it's usually a curable blood loss from GI bleeding or peptic ulcer, especially peptic ulcer disease. It's the most common cause of nutritional deficiency worldwide. The population includes females, why menstruation; children, why decreased intake, high demand because they are growing.
What are the causes? Imagine that you are a businessman; so when you have a problem, it's either decrease supply or increase demand or loss. Decrease supply is, like, nutritional deficiency or malabsorption: I'm not getting enough iron, or I'm getting enough iron, but I cannot absorb it. What's the difference? It's basically the same. Increase demand, such as increased utilization: I need more iron now, I need more and more. Or loss, such as blood loss or hemolysis: the RBC's are being destroyed. So, the causes of iron deficiency anemia are decrease supply, increase demand, or loss. Decrease supply, we said nutritional deficiency or malabsorption. Nutritional deficiency: it says prematurity; premature babies are more at risk from getting iron deficiency. Poverty and nutritional deficiency: not getting enough food or enough minerals. Also old age, the same problem as the kids' diet. Some people who are strict vegans, they are not getting enough heme iron. So, as we have said before, there are two types: the heme that we get from meat products and the non-heme from the vegetables. The heme iron is better absorbed than the non-heme. So, people who are strict vegans, they eat only vegetables; there's increased risk of getting iron deficiency anemia.
Malabsorption, such as celiac disease or post-gastric surgery. Increased demand, increased utilization, such as pregnancy: so the lady is not only feeding her body, she's feeding two bodies; she needs more. Also lactation, same concept; growth: I'm needing more iron because I'm building new cells. Loss, such as blood loss or intravascular hemolysis. Blood loss, such as peptic ulcer disease, Meckel's diverticulum. Peptic ulcers usually in adults, Meckel's in kids, because Meckel's has some gastric tissue in them sometimes, so they can bleed. Hookworm infection, hookworm such as Ancylostoma duodenale or Necator americanus. So, lost my dog, Nellie, or Necator americanus. Colon polyps can bleed; colon cancer, of course, can bleed. They relate to blood loss, which will lead to iron deficiency anemia. Intravascular hemolysis has to be intravascular; so the blood will get broken down, then eventually they will go through the kidney, and they will lose a lot of iron there. So, we have microangiopathic hemolytic anemia and a condition called paroxysmal nocturnal hemoglobinuria. These are the causes of iron deficiency anemia: decrease supply, increased demand, or blood loss.
Let's review. So, hemoglobin consists of heme and globin. Heme consists of iron and protoporphyrin. So, when I have iron deficiency anemia, iron will be decreased, heme decreased, hemoglobin decreased; that's why it's anemia—anemia: low hemoglobin and hematocrit, by definition. Hemoglobin will be low. Okay, since protoporphyrin will not have enough iron to bind with to form heme, protoporphyrin also will pile up. Okay, okay. I'm at two pieces. We have proerythroblast all the way down to the mature erythrocyte. Cells start up big, then they get smaller and smaller and smaller. So, here is the mature red blood cell. The cells are waiting for cell division, and they're waiting for iron. So, if iron is not coming, they will keep decreasing in size, like this, like this. We end up with small cells; that's why it's called microcytic anemia. They are stopped, waiting for iron. By the same token, them being so small will get the hemoglobin inside them to look relatively bigger. So, they are trying to mitigate the problem.
Clinically, iron deficiency anemia, such as any other anemia: turning pale, pale and tired. Sometimes I have angina, sometimes I have weakness, irritable, exercise intolerance. We have sometimes other associations, such as Plummer-Vinson syndrome with esophageal webs, glossitis, colitis—inflammation of the tongue and the lips. Restless leg syndrome; for an unknown reason, restless leg syndrome is associated with iron deficiency anemia. This is high-yield. Achlorhydria: we have talked about iron absorption. We have mentioned that HCl is necessary to convert the ferric iron into the ferrous, which is more readily absorbed. Also, there is an association with celiac disease, as we have mentioned; it's a malabsorption problem. We have spoon-shaped nails, called koilonychia. Koilonychia. Beeturia: you know, ten percent of the general population, when they eat beets, they get red urine. In iron deficiency anemia, almost all of them will get the beeturia. Pica: pica is craving for ice, not just ice, but any ice-containing drink, such as ice coffee. They just crave, they just want the ice. Why? I don't know. So, remember these associations. Also the pica, or pica is also known as pagophagia.
Hematology is all about lab results. The story of iron: that we have iron, the serum gets on transferrin, the binding protein, then gets stored in the tissue as ferritin. So, as an anemia, what will happen to hemoglobin and hematocrit? They'll both be low; that's a given. MCV, since it's a microcytic, MCV is below. MCH and MCHC, they'll be low. It's an iron deficiency anemia; it's an anemia. Reticulocytes will be low. Why is that? I don't have enough iron to make mature RBC's or even immature RBC's; you don't have enough iron, period. White blood cells are usually normal, except there is one exception, I'll mention it later. Platelets: platelets may get slight increase. Why is that? Because sometimes the erythropoietin is very similar to thrombopoietin; okay, that's a theory. Other theory is that, now anemia, the blood is very thin; let's try to make it thicker and more dense by producing more cells. I cannot produce RBC's, at least I can produce more platelets.
What about the iron studies? That's crucial. Serum iron definitely decreased; okay, it's iron deficiency. How about ferritin? The stored iron, the store comes from, from the serum, so they're decreased. How about TIBC? The liver recognizes the problem; says, hey, we're not having iron, let's get more carriers to try to catch the last iron molecule left; let's try our best. So, TIBC is increased. And as we have said before, iron and TIBC are always inversely related to each other. Percent saturation, of course, is decreased, because percent saturation is the iron on the transferrin, and since iron is decreased and TIBC is increased, the ratio, of course, will be decreased. How about this one, the soluble transferrin receptor, sTfR? This one will be increased in iron deficiency anemia, but normal in anemia of chronic disease, as we've said before. RDW: RDW is the variation in the sizes of red blood cells. And if you go back to our video when I've talked about RDW, Rome did not fall in a day, and neither did the bone marrow. So, it happens gradually; there is a wide variation. So, the RDW is high. But wait, there is an important piece of information here. Ferritin is an acute phase reactant, data influenced by interleukin-6. So, if I have a patient with iron deficiency anemia, I expect low ferritin; however, if he has concurrent inflammation, maybe ferritin will be high. Oh, how can I know? It will not be anchored; it will not be helpful. That's why the soluble transferrin receptor, sTfR, is not influenced by interleukin-6. So, you'll have, this one will be high. Okay, so that's how you know the difference.
So, long story short, do not rely on ferritin if you have ongoing inflammation. We all did not fall in a day; neither did the bone marrow. Start as normal-sized cells, then become micro-sized cells. Microcytic cells have increased central pallor, and since protoporphyrin is left alone, start to pile up. So, we have increased free erythrocyte protoporphyrin. There is no iron to join it; poor protoporphyrin, you'll be left alone. One of the most accurate tests to diagnose iron deficiency anemia is bone marrow biopsy, and by the way, it's very painful. The patients are very sensitive to pain. So, do we usually do bone marrow biopsy just to diagnose iron deficiency anemia? No, there is an easier way to diagnose it. Give the patient iron; if they improve, it's iron deficiency anemia; bingo. Okay, what will happen if we did a bone marrow biopsy in a patient with iron deficiency? We will have depleted iron stores evident on the biopsy. We've mentioned that iron deficiency anemia usually have normal white blood count, but there is one exception; you know what's that? Yes, when there is a hookworm infection. Hookworms such as Ancylostoma duodenale and Necator americanus.
What's the treatment of iron deficiency anemia? We start with oral ferrous sulfate. Has side effects? Yes, sometimes diarrhea or constipation, black stool, since iron will come in the stool. However, this is guaiac-negative stool, why? Because it's just iron; there is no blood. Remember, guaiac stool test detects RBC's, hemoglobin, myoglobin. Since we have only iron in the stool, it will be guaiac-negative. Failure of treatment sometimes because patients are not compliant with the treatment. Okay, also blood loss; if it's going on, it will not fix it just to give him iron. Absorption problem; this is very important. The resistant cases to treatment usually have celiac disease. Okay, what if the first one failed? Let's start intramuscular, intravenous iron. What's the biggest side effect? Anaphylaxis, especially if it contains dextran. That's it; that's iron deficiency. Please subscribe; there are new videos coming every week. Thank you for your support; I'll see you in the next video to continue talking about microcytic anemia.