Having looked at the causes of hemolytic anemia in a general way (we grouped them into hereditary and acquired groups, and defined the general clinical characteristics of each), let’s take a closer look at the specific kinds of hemolytic anemia. We’ll discuss the hereditary causes first, starting with hereditary spherocytosis.

Hereditary spherocytosis is a relatively common disorder (as far as hematologic disorders go): 1 in 5,000 people of Northern European descent have it (the incidence is lower in other racial groups). Though it is a hereditary disorder, the age of onset of clinical symptoms – and their severity – is variable. The clinical symptoms are usually described as a triad of mild anemia, intermittent jaundice, and splenomegaly. Most patients are able to make enough new red cells to replace the ones that are being prematurely destroyed – so most of the time, there is a mild anemia (or no anemia at all). It’s when a patient gets exposed to something that is nasty to red cells, like parvovirus B19 infection (which wipes out red cells), that the patient can enter what’s called a “crisis” – meaning that the already maxed-out bone marrow can’t keep up with the newly increased demand, and a sudden worsening of the anemia occurs. In these crises, the patient will likely experience clinical signs of anemia (fatigue, for example) and jaundice (from the increased hemolysis).

The basic defect in hereditary spherocytosis involves components of the membrane cytoskeleton (including spectrin, ankyrin, or band 4.2). This means the red cell membrane is unstable, and there is loss of bits of membrane (which means that the cells round up, making spherocytes, which are the darker, smaller red cells with no central pallor in the image above). The big problem in this disorder is that the macrophages in the spleen see these abnormal cells and eat them up! It’s hard for spherocytes to make it through the cords of Bilroth (they aren’t nice and deformable like regular biconcave-disc-shaped red cells), so they are detained in the spleen, making it easy for the macrophages to get ahold of them. Spherocytes are also more fragile than normal red cells, so they bust open more easily. However, it’s the removal of red cells by the spleen that is the main cause of this anemia.

So when you look at a blood smear of a patient with hereditary spherocytosis, you’ll see spherocytes (you didn’t need me to tell you that). Depending on the severity of the patient’s genetic spectrin abnormality, there may be a few spherocytes, or a ton of spherocytes. You’ll also see evidence of accelerated hematopoiesis in the form of reticulocytosis (actually, you should say “polychromatophilia” if you’re describing a normally-stained blood smear. Reticulocytes are only visible on a supravital stain; on a regular Wright-Giemsa stained blood smear, you call those same cells polychromatophilic cells. You can see a polychromatophilic cell in the image above directly below the center neutrophil. If it were a supravital stain, you’d call that same cell a reticulocyte. But that’s getting a little picky.). If the bone marrow is really cranking out red cells, you might see some nucleated red cells in the blood too.

Therapy for this disorder, if necessary (many patients can get along just fine), involves splenectomy (if the patient can tolerate it). The spleen is the site of destruction of the red cells in hereditary spherocytosis. Remove the spleen, and you remove the place where the cells get destroyed! You’re not curing the genetic defect, of course; the patient will still have some spherocytes in the blood. But you are treating the disease so effectively that the patient should not have any further clinical symptoms. If splenectomy is not an option, then the patient may need red cell transfusions during crises.

Photo credit: Ed Uthman (http://www.flickr.com/photos/euthman/2989437967/).

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11 Responses to Hereditary spherocytosis

  1. Kathy says:

    I have Hereditary Spherocytosis and I had my spleen removed, that’s the only cure (so to speak) my spleen weight 10pds when they removed it, so don’t wait! Have it removed, you can live a normal life without it….But one thing and this is big, do not forget to get that pneumococcal vaccine it very important, and to keep getting it every 5 yrs after….I also passed it onto 2 of my 5 children, and so far only 1 of my 8 grandchildren have it……

  2. admin says:

    Wow – 10 pounds! That is really, really big! I’m glad you are doing well. Yes – you’re absolutely right: you need to get vaccinated against bugs that normally get killed by the spleen. Streptococcus pneumoniae has a huge capsule, so it’s hard to kill. It only really gets killed during its passage through the spleen, where it gets detained long enough for macrophages to get their grubby paws around it. Other than needing to be vigilant about vaccines, you should have no other health issues. Thanks for sharing your story.

  3. Barbi says:

    I have HS as well. I passed it on to both of my children. I had my spleen removed when I was eight and much to the surgeon’s surprise I had three of them. One right behind the other. I also had the bilirubin stones that were removed as well. With my son, I had them remove his before he started school because it was so enlarged and I wanted him to have a normal life. I always had to sit out in gym and on the playground because they were afraid I would rupture. We are very vigilant about vaccines, but last night I had an episode that scared my family so bad they rushed me to the ER. I was experiencing tightness in my chest to the point that I felt like I was in a vise. The ER doc swears that my blood is too thick with white cells and that was what was causing my pain. Has anyone else had this experience? If so what type of treatment was used?

  4. admin says:

    A person’s white blood cell count needs to be extremely elevated before blood sludging occurs! I doubt that was the cause of your chest pain; it would be good to see your CBC, however. If you were very dehydrated, that might have contributed to your symptoms. Best wishes to you and your son.

  5. Vaun says:

    Gday. I’m a 32 yr old male with hs. I got mine out when I was about 12 I think. Have been fine since. Live a very healthy active life which I think has definitely helped. I found out I had gallstones years ago when I had X-rays on my back but they have never bothered me. I just found out I’m going to be a father for the first time and I’m trying to find out, do males pass hs on to their children?

  6. dr.manar says:

    HS is a gentic disease,with autosomal inheritence,one parent is only needed to transmit the disease to his future kids,the chances of having an affected child is 50%(both sexes)

  7. Kristine says:

    That’s true!

  8. aishah says:

    I have not seen this disorder in patients I have seen so far in Malaysia. I guess its little rare here. My hematologist do tell me to look for other causes of spherocytosis if we see one.

  9. Debbie pressler says:

    It was not until my second child was born that I was diagnosed with HS. She was so jaundice that she had to be under lights for 6 weeks with the possibility of an exchange blood transfusion. At 8 weeks she had to have a blood transfusion. She, my mom and myself were tested and confirmed we all three had hs. The doctors told my parents I had an enlarged spleen and had my spleen removed when I turned 5. My mom had her spleen removed at 22. My daughter had her spleen along with gall bladder (because of gall stones) and appendics removed at 5 years and my third child had to have a transfusion at 4 years and had his spleen removed at 5 years. I now have a grandson who possibly has it. They have seen some spherocites.

  10. joly says:

    hi….tanx for coment

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