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Low Hemoglobin in Children
In this segment, Frederick S. Huang, MD, Washington University pediatric oncologist at St. Louis Children’s Hospital, discusses low Hemoglobin, treatment options and when to refer to a specialist.
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Learn more about Frederick S. Huang, MD
Frederick S. Huang, MD
Frederick S. Huang, MD cares for children with cancer and blood disorders. Dr. Huang is consistently recognized in "The Best Doctors in America" list.Learn more about Frederick S. Huang, MD
Transcription:
Low Hemoglobin in Children
Melanie Cole (Host): Anemia is not a specific disease entity, but a condition caused by various underlying pathologic processes. My guest today is Dr. Frederick Huang. He’s a Washington University Pediatric Oncologist at St. Louis Children’s Hospital. Welcome to the show, Dr. Huang. What would be some clinical indications for a blood count in a child?
Dr. Frederick Huang (Guest): I think it would be a good idea to get a complete blood count, or a CBC when you suspect that there is a problem with one of three main blood cells, the white blood cells, the red blood cells, or the platelets. What I’d like to talk about today is what happens when a CBC is obtained, and it is discovered that the hemoglobin, which is the reflection of red blood cells, is low.
There are a number of causes for a low hemoglobin or anemia. The most common reason in children is a deficiency in iron and the way most practitioners suspect that that is the case is that the low hemoglobin is associated with a low mean corpuscular volume, or MCV, which is just a fancy laboratory way of saying what the size of the red cell is. When there are a low hemoglobin and a small red blood cell size, iron deficiency is at the top of the list. The other possibility might be that it would be related to a hemoglobinopathy like Thalassemia.
Most recommendations suggest that if you see a low hemoglobin and a low MCV, that a trial of iron be tried to see if the lab results get better. If not, then one could get a test called a ferritin, which looks at the amount of iron in the body, to be sure that it was really iron deficiency or not. The other thing that could be ordered is a hemoglobin analysis, also known as a hemoglobin electrophoresis because that test can help reveal whether there is an abnormal hemoglobin, like one might see in Thalassemia.
I think that it is fairly standard for most practitioners to feel comfortable going this far for a workup of a low hemoglobin, but what I’d like to spend a little time talking about today is how I might approach a low hemoglobin when there has not been associated low MCV. In those cases, I like to get another test called a reticulocyte count, which is a measure of the number of young red cells that are circulating, so it can be a helpful test in trying to decide if the cause of anemia is because red cells just aren’t being made – a production problem, or that red cells are being made, but are being destroyed earlier than one might expect. The way to sort those two possibilities out is to see if the reticulocyte count is low or high. If the reticulocyte count is low, then the decreased hemoglobin is likely to be a result of decreased production. Some causes for that might be that you’re born with an inability to make red cells, a condition known as Diamond-Blackfan anemia. It might be that your bone marrow, where the red cells are made is being suppressed by a drug like some antibiotics or an infection like some viruses. It might also be that you don’t make enough hormones known as erythropoietin that is critical for the production of red blood cells. That can sometimes be seen when you have kidney disease. A low hemoglobin, in association with a low reticulocyte count, suggests one of these kinds of red cell production problems.
The other pathway to consider would be a low hemoglobin in association with a high reticulocyte count, which suggests that the red cells can be made but they're being destroyed and therefore, the bone marrow is compensating by making a lot of new, young red blood cells. Certain causes that you might want to think about include, again, problems with hemoglobin. One of the most common problems with hemoglobin is something known as Sickle Cell Disease, which is often appreciated on the newborn screen for newborns. It might be a problem with the amount of a certain enzyme inside red blood cells, the most common one being glucose-6-phosphate dehydrogenase or G6PD. A deficiency of G6PD can lead to red cell destruction and anemia.
Another reason for red cell destruction might be an inherited condition known as hereditary spherocytosis. Finally, another important reason might be that the patient has an antibody that’s directed against the red cell, which leads to its premature destruction, a condition known as autoimmune hemolytic anemia. I’ve just discussed a large number of diagnostic possibilities, but I think that dividing them into one of two categories, production problems or destruction problems, through the aid of a reticulocyte count can help better organize the thinking of the possibilities and therefore, organize the consideration of what additional tests the practitioner might want to order into order to confirm a particular possibility, or not.
Melanie: And, Doctor, what tests would you like pediatricians to order?
Dr. Huang: I think that what would be very helpful is to always include a reticulocyte count along with the CBC if one is worried about anemia because it’s often easier to get it to get it and use those two pieces of information to wade through the possibilities than it is to order the complete blood count alone, which is more common, but can sometimes be inconvenient if a reticulocyte count is needed.
Melanie: And when would you like them to refer to a specialist?
Dr. Huang: I think that a referral to a specialist should happen whenever the provider feels that it would be helpful, but I think that every practitioner’s going to have a certain familiarity with the possibilities I just discussed and the tests that could be helpful in determining those possibilities. A referral would always be appropriate when a practitioner reaches their limit with regards to their familiarity with the right kinds of tests to order and how to interpret the results.
Melanie: So wrap it up for us, with your best advice for other providers and pediatricians about what you would like them to know about low hemoglobin and the tests to order.
Dr. Huang: I think the biggest lesson is that low hemoglobin is most commonly due to iron deficiency and that the standard approach to looking at a low hemoglobin and checking the MCV to see if it’s also low in order to provide a little evidence that the anemia is due to iron deficiency is a very good first approach, but I think that in all other cases, having a reticulocyte count can be very beneficial with regards to the thinking and the evaluation of that low hemoglobin because it allows one to organize a fairly long list into a more thinkable list and be a good guide for the practitioner.
Melanie: And tell us about your team. Why is St. Louis Children’s Hospital so great to work with?
Dr. Huang: Well, I’m a very lucky person because I’m part of a very talented and committed team of physicians, nurses, and staff. Our goal every day is to take care of children who have cancer and blood problems, like anemia. We are always ready and willing to do what it takes to figure something out and have the child be healthier and happier.
Melanie: Thank you, so much, for being with us, today. A physician can refer a patient by calling Children’s Direct Physician Access Line at 1-800-678-HELP, that’s 1-800-678-4357. You’re listening to Radio Rounds with St. Louis Children’s Hospital. For more information on resources available at St. Louis Children’s Hospital, you can go to StLouisChildrens.org, that’s StLouisChildrens.org. This is Melanie Cole. Thanks, so much, for listening.
Low Hemoglobin in Children
Melanie Cole (Host): Anemia is not a specific disease entity, but a condition caused by various underlying pathologic processes. My guest today is Dr. Frederick Huang. He’s a Washington University Pediatric Oncologist at St. Louis Children’s Hospital. Welcome to the show, Dr. Huang. What would be some clinical indications for a blood count in a child?
Dr. Frederick Huang (Guest): I think it would be a good idea to get a complete blood count, or a CBC when you suspect that there is a problem with one of three main blood cells, the white blood cells, the red blood cells, or the platelets. What I’d like to talk about today is what happens when a CBC is obtained, and it is discovered that the hemoglobin, which is the reflection of red blood cells, is low.
There are a number of causes for a low hemoglobin or anemia. The most common reason in children is a deficiency in iron and the way most practitioners suspect that that is the case is that the low hemoglobin is associated with a low mean corpuscular volume, or MCV, which is just a fancy laboratory way of saying what the size of the red cell is. When there are a low hemoglobin and a small red blood cell size, iron deficiency is at the top of the list. The other possibility might be that it would be related to a hemoglobinopathy like Thalassemia.
Most recommendations suggest that if you see a low hemoglobin and a low MCV, that a trial of iron be tried to see if the lab results get better. If not, then one could get a test called a ferritin, which looks at the amount of iron in the body, to be sure that it was really iron deficiency or not. The other thing that could be ordered is a hemoglobin analysis, also known as a hemoglobin electrophoresis because that test can help reveal whether there is an abnormal hemoglobin, like one might see in Thalassemia.
I think that it is fairly standard for most practitioners to feel comfortable going this far for a workup of a low hemoglobin, but what I’d like to spend a little time talking about today is how I might approach a low hemoglobin when there has not been associated low MCV. In those cases, I like to get another test called a reticulocyte count, which is a measure of the number of young red cells that are circulating, so it can be a helpful test in trying to decide if the cause of anemia is because red cells just aren’t being made – a production problem, or that red cells are being made, but are being destroyed earlier than one might expect. The way to sort those two possibilities out is to see if the reticulocyte count is low or high. If the reticulocyte count is low, then the decreased hemoglobin is likely to be a result of decreased production. Some causes for that might be that you’re born with an inability to make red cells, a condition known as Diamond-Blackfan anemia. It might be that your bone marrow, where the red cells are made is being suppressed by a drug like some antibiotics or an infection like some viruses. It might also be that you don’t make enough hormones known as erythropoietin that is critical for the production of red blood cells. That can sometimes be seen when you have kidney disease. A low hemoglobin, in association with a low reticulocyte count, suggests one of these kinds of red cell production problems.
The other pathway to consider would be a low hemoglobin in association with a high reticulocyte count, which suggests that the red cells can be made but they're being destroyed and therefore, the bone marrow is compensating by making a lot of new, young red blood cells. Certain causes that you might want to think about include, again, problems with hemoglobin. One of the most common problems with hemoglobin is something known as Sickle Cell Disease, which is often appreciated on the newborn screen for newborns. It might be a problem with the amount of a certain enzyme inside red blood cells, the most common one being glucose-6-phosphate dehydrogenase or G6PD. A deficiency of G6PD can lead to red cell destruction and anemia.
Another reason for red cell destruction might be an inherited condition known as hereditary spherocytosis. Finally, another important reason might be that the patient has an antibody that’s directed against the red cell, which leads to its premature destruction, a condition known as autoimmune hemolytic anemia. I’ve just discussed a large number of diagnostic possibilities, but I think that dividing them into one of two categories, production problems or destruction problems, through the aid of a reticulocyte count can help better organize the thinking of the possibilities and therefore, organize the consideration of what additional tests the practitioner might want to order into order to confirm a particular possibility, or not.
Melanie: And, Doctor, what tests would you like pediatricians to order?
Dr. Huang: I think that what would be very helpful is to always include a reticulocyte count along with the CBC if one is worried about anemia because it’s often easier to get it to get it and use those two pieces of information to wade through the possibilities than it is to order the complete blood count alone, which is more common, but can sometimes be inconvenient if a reticulocyte count is needed.
Melanie: And when would you like them to refer to a specialist?
Dr. Huang: I think that a referral to a specialist should happen whenever the provider feels that it would be helpful, but I think that every practitioner’s going to have a certain familiarity with the possibilities I just discussed and the tests that could be helpful in determining those possibilities. A referral would always be appropriate when a practitioner reaches their limit with regards to their familiarity with the right kinds of tests to order and how to interpret the results.
Melanie: So wrap it up for us, with your best advice for other providers and pediatricians about what you would like them to know about low hemoglobin and the tests to order.
Dr. Huang: I think the biggest lesson is that low hemoglobin is most commonly due to iron deficiency and that the standard approach to looking at a low hemoglobin and checking the MCV to see if it’s also low in order to provide a little evidence that the anemia is due to iron deficiency is a very good first approach, but I think that in all other cases, having a reticulocyte count can be very beneficial with regards to the thinking and the evaluation of that low hemoglobin because it allows one to organize a fairly long list into a more thinkable list and be a good guide for the practitioner.
Melanie: And tell us about your team. Why is St. Louis Children’s Hospital so great to work with?
Dr. Huang: Well, I’m a very lucky person because I’m part of a very talented and committed team of physicians, nurses, and staff. Our goal every day is to take care of children who have cancer and blood problems, like anemia. We are always ready and willing to do what it takes to figure something out and have the child be healthier and happier.
Melanie: Thank you, so much, for being with us, today. A physician can refer a patient by calling Children’s Direct Physician Access Line at 1-800-678-HELP, that’s 1-800-678-4357. You’re listening to Radio Rounds with St. Louis Children’s Hospital. For more information on resources available at St. Louis Children’s Hospital, you can go to StLouisChildrens.org, that’s StLouisChildrens.org. This is Melanie Cole. Thanks, so much, for listening.