Click here to view next page of this article

 

New Treatments for Iron Deficiency

There are a number of causes of iron deficiency, but Iíd like to say that basically - for the adult hematologist and the adult internist - when you see iron deficiency you need to think of blood loss and you need to identify the site of blood loss iron deficiency anemia. But it can occur because of increased physiological requirements. This especially occurs in women of childbearing age in which menstruation, pregnancy and lactation all have increased requirements of iron, and in infants and adolescents where the growth spurt is associated with high iron requirements. You can also see iron deficiency due to decreased absorption in certain circumstances, such as gastric surgery in which you have the absence of the acid production that helps absorption. If you have a resection of the proximal small bowel, that can also lead to iron deficiency because the absorptive surface is lacking. And inflammatory bowel disease and celiac disease can lead to a malabsorption of iron. But, as I said, in 90% or more of the cases there is loss of iron and you have to think, very commonly the loss of iron can be due to gastrointestinal bleeding.

This is a slide to remind us that even though we are practicing in the United States, we have to think of the global picture of iron metabolism and in the tropics, hookworm infestation is a very common cause of iron deficiency. This slide shows the hemoglobin concentration on the horizontal axis in a study that was done in the tropics, and the school count of hookworm ova on the vertical axis. And, as you can see, there is a marked decrease in the hemoglobin.

Children of early age, between the ages of six months and two years, can have impaired growth and psychomotor development because of iron deficiency. In adults, iron deficiency is associated with fatigue, irritability and decreased work productivity. Pica is a very common finding in patients with severe iron deficiency and you will find it if you ask the patients about it; do they eat clay? Do they eat laundry starch?

What are the laboratory findings of iron deficiency? Well, one of the very first ones that you can see on a CBC is an increase in the red cell distribution width, as even early iron deficiency begins to be associated with an increased variability in the size of the red blood cells. As iron deficiency becomes more established, you see a decrease in the MCV, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red blood cell count, hemoglobin concentration and hematocrit.

Now iron deficiency is kind of the prototype of a microcytic hypochromic anemia, but itís important to remember that there are a number of other causes of microcytosis and to keep this differential diagnosis in mind; the anemia of inflammation can be associated with a mild decrease in the hemoglobin and a mild decrease in the MCV, which ranges in the lower limit of normal to the upper limit of being abnormal. Thalassemia minor and thalassemia major, beta thalassemia major and beta thalassemia minor, are both associated with microcytosis. Hemoglobin H disease, the deletion of 3-alpha globin chains is associated with microcytosis, as is hemoglobin E trait, hemoglobin C disease and hereditary sideroblastic anemias. You always have to have a differential diagnosis in mind when you look at the defining features of the condition, so we are always looking at the serum iron and the transferrin saturation and we know that the low concentration and the low saturation is associated with iron deficiency. But there is quite a differential. Of course iron deficiency causes this constellation, but also inflammation.

In that setting, the bone marrow is the final arbiter. The bone marrow is the gold standard of diagnosing iron deficiency. You do this on the aspirate. You donít do it on the core because the core loses a lot of iron during the decalcification process. So you look at the iron stain of the aspirate. The other caveat is that your aspirate has to have good spicules. If you have an inadequate aspirate that really doesnít have any spicules, you cannot grade iron stores. So you have to have a good aspirate that has good spicules on it.

Okay, how about the management of iron deficiency, once weíve made the diagnosis? Well, first and foremost, you have to look for a source of blood loss, and you have to rule out the possibility of a gastrointestinal malignancy or a genitourinary malignancy. So you have to think; could there be a colorectal cancer? A gastric cancer? An esophageal cancer? An endometrial cancer or a bladder cancer thatís leading to this iron loss? And you have to rule out the

So once youíve made the diagnosis, youíve found the cause of it, youíve resected the curable colon cancer or gastric cancer, then you worry about treatment. Typically we treat iron deficiency with an oral iron preparation. Typically 325 mg ferrous sulfate tablets a day provides 200 mg of elemental iron. You can actually treat iron deficiency very well with a nontoxic form of very fine elemental iron power called carbonyl iron. There is a big problem with iron poisoning in children when they get into the mothers iron tablets, that are actually synthesized to look like

There are problems with iron therapy. One, are the gastrointestinal side effects, which are really quite common. This is really the reason usually why people donít respond to oral iron is because theyíve had side effects and they are not taking the medication. So there are a couple of things you can do. One is, you can decrease the ferrous sulfate from 325 mg three times a day and give it twice a day or once a day. And it turns out that if you corrected the site of bleeding, you can

If the person takes the iron preparation, you will correct the anemia just as fast with oral iron as you will with parenteral iron. In almost all circumstances, itís better to find ways to get the patient to comply with the oral therapy than to resort to