Health and medicine
Created by Nauroz Syed.
- So let's talk about some of the differences between anemia of chronic disease and iron-deficiency anemia, because really these two diseases present very similarly. Both of them are going to have patients that present with signs and symptoms of anemia. So, patients that are chronically fatigued and feeling weak, looking paler than usual, and maybe experiencing some shortness of breath. And really, when you go to draw the basic anemia labs, take a look at what's going on in the blood, you'll see that both of them are microcytic anemias. So, really the only way to tell these two diseases apart is to draw iron studies. So let's take a look at what some of those values would show. So, here's some of the values that you get back when you draw iron studies, and we already went through this for iron-deficiency anemia, but let's just do it again for practice sake. So, with iron-deficiency anemia you'd expect your serum iron to be decreased, right? Hence, the iron deficiency part of it all. The percent saturation or the percentage of total binding sites on the transferrin molecules that are actually occupied by iron would also be decreased. The total iron binding capacity in iron-deficiency anemia is increased, and we said that that was the body's compensatory mechanism to deal with the deficiency in iron. So what the body does to deal with the shortage of iron is increase its production of transferrin molecules. It makes more transferrin, puts it out into the blood, so that the transferrin can go out there and bind to more iron, to find more iron and bind to more of it, okay? And ferritin, which is reflective of the amount of iron that's in storage in the body is decreased in iron deficiency, okay? So, those are the values for iron-deficiency anemia. Let's compare that with what you see in anemia of chronic disease. So just as an overview, once again, anemia of chronic disease is a disease where you have some underlying inflammatory condition, and as a result of it, you have an increased production of a molecule called hepcidin, and what hepcidin does is it, number one, decreases the absorption of iron from the gut, and it also decreases the recycling of iron from the breakdown of red blood cells. So, really what your body is trying to accomplish in this disease is, it's trying to limit how much iron is coming into the body and at the same time it's trying to tuck away as much iron as possible into storage, so that very little is present in the blood. In essence, the body's trying to play keep away with the iron, away from bacteria and inflammatory cells, because they really need it to thrive and to grow, okay? So, you'd expect that the serum iron in anemia of chronic disease would be decreased. That's exactly what the body's trying to accomplish. It wants very little iron present in the blood. The percent saturation, which is again the percentage of transferrin binding sites that are actually filled up with iron, would also be decreased. The total iron binding capacity, or the amount of transferrin that's in the blood in anemia of chronic disease, is decreased. And again, this makes sense. It goes totally in line with what the body's trying to accomplish. It decreases the production of transferrin so that there's less transferrin out there in the blood trying to bind to iron, okay? And finally, the ferritin, which is reflective of the total amount of iron in storage in the body in anemia of chronic disease is characteristically increased, and this is because once again the body has tucked away as much iron as possible into storage, okay, which is reflective of what you see with ferritin. So, really there are a couple of differences between iron-deficiency anemia and anemia of chronic disease. Firstly, iron-deficiency anemia is really a disease of total body depletion of iron, and these lab values reflect that very well, especially the ferritin. This tells you that there is no iron in the body, not even in storage, not in the blood, not in the storage, not anywhere. Anemia of chronic disease, however, isn't necessarily a disease where you have a depletion in iron. Instead, you'll see an increase in ferritin, so that tells you that there's iron in the body, it's just tucked away, away from the access of bacteria and inflammatory cells. Now, also another difference between these two diseases is that in iron-deficiency anemia the body is doing its absolute best to increase the amount of iron available in the serum, and you see that with the total iron binding capacity. It increases the production of transferrin. It does its best to try to bring more iron into the body and into the blood. However, in anemia of chronic disease the body is trying to accomplish the exact opposite. It's decreasing its production of transferrin so that you have as little iron as possible in the serum, and the increased ferritin also reflects that the body's trying to hide away its iron in storage. So, in summary, those are some of the differences between anemia of chronic disease and iron-deficiency anemia, which again, you really rely on these iron studies to differentiate between, because they present very similarly. What's important to keep in mind is that these are both microcytic anemias.