This page has moved. Click here to view.

 

Anemia

The definition of anemia. The hemoglobin is low but thatís not really the true definition of anemia in that there is a reduction in red blood cell mass but there is also a corresponding decrease in the oxygen carrying capacity. Because some patients can be completely asymptomatic with a low hemoglobin and theyíll have to be treated. You know, athletes, generally their red blood cell mass is high but they can go low and because they are so well conditioned, donít have coronary artery disease, itís not a big deal so they can go down to a hemoglobin of 9. Theyíll notice it but in comparison in a person with severe coronary artery disease, a drop in a gram of hemoglobin which even though it might be in the normal range, letís say you have an adult male, he has a hemoglobin of 12 and it goes down to 11 and he has severe coronary artery disease, that could be a significant reduction because there his oxygen delivering capacity canít keep up with the demand and anemia, anemea

Now, what is more helpful and not always seen on every CBC is the red blood cell distribution width because there can be variations. And this is a measurement of anisocytosis Ė trying to look at how big these are, and this is helpful in helping you, especially if you have a microcytic and a hypochromic anemia but especially a microcytic anemia, is distinguishing between a thalassemia and an iron deficiency anemia because if a patient has thalassemia, the RDW tends to be very narrow. It will be in

Iím going to go through a few points and this is taken from a hematology textbook but this is looking at what are normal values and the important thing to remember relative to normal values is there are differences relative to age, relative to sex and relative to race and in particular looking at the

Now, when we get to adults we start to see there is a transition. In the teenage years the hemoglobin starts to rise and for adults, normal hemoglobins for a female is 14 with a variation of 2, so you can see it on either side. Generally, women tend to run 1 to 2 grams lower than males. And itís not because of

Now, if you took an African American, generally they run a hemoglobin of about a gram lower and this probably goes back to even with the idea about sickle cell that running a lower hemoglobin may relate to malaria and itís just normal genetics. So if we saw an African American female with a hemoglobin of 11, that doesnít necessarily mean she is anemic. That would just be normal for her age, her race and for her sex in the same way that if we saw a Caucasian male with a hemoglobin of 18, that doesnít necessarily mean that they have polycythemia vara. So each way has to 

Now, Iím going to come back and say well where do red blood cells come from? And Iím obligated as a hematologist to show you a stem cell tree. But itís important. Itís relative to think that the stem cell is a self renewing and itís capable of giving rise to all the blood elements including red blood cells, including platelets and including the white blood cells. And itís important because many of the defects may arise at the level of the stem cell. A patient with a myelodysplastic syndrome. Something you see in your elderly population. Probably markedly underdiagnosed. The 80-year-old gentleman walks in, he has a hemoglobin of 8, his platelets are about 125, his white count is 2.9 and yet the first thing we

The way that red blood cells are regulated, red blood cells, primarily 90-95% originate in the bone marrow. Other sites of red cell production can be the liver and the spleen and when there is increased stress put on the bone marrow, these can become sites of hematopoiesis. But again 95% or greater

Again, it comes back to our definition of anemia. Itís not looking at purely how much red blood cells are there but itís ability to deliver oxygen and when it senses that it is not able to deliver oxygen, with this oxygen sensors which are present in the peritubular interstitial cells of the kidney it releases erythropoietin. Erythropoietin is constantly being produced, is carried through the bloodstream and

Always remember that when you get erythropoietin levels, and I will give you an example is your patients with AIDS, is that you would see that the patient would have a hemoglobin of 9, you do an erythropoietin level and itís 75. And you go well, normal erythropoietin level at you institution is about

The way to think about anemia is three-fold. There can only be three reasons a patient is anemic. (1) They canít make enough and that would be production. The second reason is that when they do make it they destroy it. So that would be destruction. The third is that if

Just as we were taught in medical school, probably the most important thing that can help us and probably in 75% of the cases of diagnosing the cause of anemia is through a good history and physical examination. So as part of our history of present illness, we want to come back to our severity and our duration of the signs and symptoms. Again, this will help us relative to how quickly was the onset

Medications is extremely important. Patients who are on anticoagulants or drugs that may predispose the patient to bleeding such as aspirin and nonsteroidal anti-inflammatory drugs should be kept in consideration. In addition, drugs that can be toxic to the kidneys because renal insufficiency again leads to decreased erythropoietin production should be sought out and Iím going to go through some

In regard to medication, I like to think of two things. One that can lead to hemolysis and one that can inhibit production and medications that have commonly associated with hemolytic anemia include quinidine, quinine, the sulfonamides, thiazides, penicillin, cephalosporins and isoniazid. And as thereís a rise in tuberculosis, that will probably be a more common thing. So these are 

What is more prevalent are drugs that can actually inhibit production and these would include most chemotherapy agents that goes back to our history of cancer and then Bactrim and Septra. Again, with the incidence of HIV within the population and a large amount of patients may be chronically on Bactrim and Septra, similarly AZT, acyclovir, phenobarbital, diphenylhydantoin and oral contraceptives. So we can all just think about in our 

The physical examination is very important. Just the general appearance. Do these patients look cachectic? Are they malnourished and therefore may be B12 or folate deficient. Do they have pallor? I mean, they look as white as a ghost. It goes along with it. You can tell a patient who is more pale than another and that would lead you to having a suspicion of those individuals being anemic. We want to do

Neurologic examination, that I forgot to mention, is again B12 and folate deficiency. If you are severe enough to have an anemia as a direct result of B12 and folate, you can also worrying about having a neuropathy at the same time. So we have our history and we have our physical examination and then we have what should be enough along with what we need is our CBC. And the CBC should contain hemoglobin, hematocrit, it should have a red blood cell indices, it should have a reticulocyte count. It will also have our white blood cell count, again, is it high, low and again is it a related stem cell disorder.

Then weíll look at our peripheral smear and on there weíre going to see our white blood cells, we might see in the neutrophils, multiple segments, which is a sign of B12 and folate deficiency, weíre going to see if there are blasts, weíre going to see if there are red blood

The only other potential helpful one is the LDH and that can be seen in a number of disorders but it can also be seen in hemolysis. So after we have all this information, our initial assessment is to determine whether it is acute blood loss, hemorrhage or later and in that

Now, in loss we should see that the reticulocyte count is up but it could be down or it could even be normal. The reason that would be, say if you have a patient with peptic ulcer disease and theyíve been doing this slow bleed, just oozing out for several months, eventually the production is kept up. Itís initially high and then all of a sudden it starts going away with the iron stores and all of a sudden now it