What is essential thrombocythemia? | Hematologic System Diseases | NCLEX-RN | Khan Academy

What is essential thrombocythemia? | Hematologic System Diseases | NCLEX-RN | Khan Academy

– Essential thrombocythemia is a disorder where you have too many platelets or thrombocytes in your blood. It’s one of our myeloproliferative disorders. So let’s recall how this all begins. Platelets are first generated in the bone marrow and remember the bone marrow is located in the shaft of long bones like our femur and it all begins with this cell which is called a pleuripotent meaning with the ability to do many things so pleuri meaning plural, potent meaning ability, hematopoetic meaning relating to blood stem cell. A pleuripotent hematopoetic stem cell. This guy can then embark on two different types of lineages. This one down here we’re not going to talk about, lymphoid stem cell because I’ve mentioned that before. But let’s focus here, on they myeloid stem cell. Remember there are six different things that can come off a myeloid stem cell. And I won’t talk about them in detail here but I’ll just draw them out for reference. But our focus for this conversation will be on the sixth
thing that can be made. And it follows this path here that begins with a megakaryoblast, a megakaryoblast. Which just means a cell that
has a really big nucleus. So that’s what karyo means,
a really big nucleus. That will divide and
mature into a megakaryocyte which will do this crazy
thing where it will break into pieces like
that so it just fractures and then produces a bunch of these little dudes right here which are just called thrombocytes or as you may recall, platelets. Thrombocytes or platelets. Remember platelets are
for our clotting system. They make sure we don’t bleed out when we sustain an injury. So for example, imagine we get poked right here or we’re stabbed and then we start bleeding. Well our platelets here will then come on over and start aggregating, aggregating or start forming the early parts of a clot that will help close off this wound an
then stop all that bleeding. Now another thing to remember about platelets is that over time they can get sheared as they pass through the vasculature and actually become messed up. So I’m trying to show these deformed platelets right here. So I’ll drive that home and just write that they are deformed, if my drawing doesn’t make sense. And they’re no longer effective. We need to get rid of them. And so they go to the spleen. Our spleen right here will then act as a filter for the blood and destroy any deformed or unusual blood cells that are passing through. And that’s kind of what happens for a platelet throughout it’s lifetime. The problem with essential thrombocythemia is that you have a defect around here before you make the megakaryoblast, where your JAK 2 kinase, I’ll write that here, it’s
JAK 2 kinases protein. It’s a regulator protein that determines whether it’s an
appropriate time for a cell to divide and go forward
with it’s maturation. This protein is set in
the on mode which just keeps telling megakaryoblasts, keep on dividing, keep on
making these platelets. And so you end up with
a bunch of platelets which can cause a variety
of distinct things to happen to you which will then present as signs and symptoms of
essential thrombocythemia. Now one of the earliest
things that we know happens, so I’ll write first here just because it’s early. You can end up having what are called, thromboses which just mean clots which would make sense because you have a lot of platelets in your blood stream, I’ll write plt for platelets and so these platelets will go around and make platelet plugs everywhere but there are three main places we notice them. First there’s the head where you can end up having symptoms such as headache, dizziness or even weakness which can show up like a facial paralysis or even slurred speech which is not too different from a stroke which sure enough is what happens when you have a lot of platelet plugs that
accumulate in your brain. The other two places your platelet plugs will predominately accumulate and I’ll group these together. That includes your hands and your feet. And when these platelet
plugs accumulate here, I’ll draw an example in
this hand right here. So this artery, kind of branches like this and let’s say it goes
to the tip of your thumb and then from there you need to have a return of the venous
blood flow up this way but imagine you have platelets clotting over here and forming a plug and it makes it difficult for blood to flow from the arterial part to the venous part and so you end up not having oxygenated blood go to your tips of your fingers or your toes. That can manifest as two things, you can get some numbness or even burning. Now aside from thromboses, the next thing or the second thing that can happen is bleeding and that’s because the presence of so many platelets in your blood stream will cause you to use up
ingredients for clotting. Meaning that when you
sustain a real injury and when you really need to clot, your platelets fail. Now this can manifest as a nose bleed or imagine if you were walking through a really crowded room and you just bump your thigh against a table or a chair, well you’re not supposed to have an effect just from simply bumping your thigh on something but because you’re not clotting, you can
actually form a bruise and that can happen
with even the most mild knock against a solid object. And lastly, remember that since platelets go to the spleen to be destroyed, if you have a lot of
platelets coming here, your spleen is going to be kicked into overdrive,so it’s going to be a lot bigger than what
I’ve drawn right here. So you’re going to get a mega spleen which we call splenomegaly. So those are some of the things we can look for if we suspect essential thrombocythemia. But how do we diagnose it? Well while this isn’t one of the first line things you’d look for, sort of a slam dunk finding would be the presence of JAK 2 kinese mutation suggesting that we indeed have a myeloproliferative disorder. But a more specific thing to look for is the number of platelets that this patient has because if that number is greater than 450,000 for two or more months, then that’s pretty suggestive. The other thing that’s knows about essential thrombocythemia is that it’s a diagnosis of exclusion which means you just have to make sure other disorders aren’t present before you can conclude a patient has
essential thrombocythemia. That means that you need to exclude things like other
myeloproliferative disorders as well as causes of inflammation because that will cause the number of platelets to increase and there are a few other things I won’t list here that could suggest why they have such a high count of platelets. And finally the last thing that you can do which is rarely done, is
a bone marrow aspiration to check to see if there’s a bunch of megakaryoblasts or cytes
found in the bone marrow and then following the diagnosis, what can we do to treat
essential thrombocythemia? Well the strategy for treatment
depends on their risk. The risk for having bad outcomes related to thromboses or bleeding. If they’re low risk,
things like if they’re young of age or they don’t have very severe symptoms, than all they need is a mild anti-coagulant or something that prevents clotting like aspirin. Remember that one of the first things that happen when you have too many platelets in your
circulation are thromboses. So aspirin will decrease
the risk of having these clots or thromboses. Now if they’re high risk, meaning that they’re older or they’ve got other chronic diseases or if they have more severe symptoms,
you can try a few things. First, you can give them hydroxyurea. Hydroxyurea is a drug that will decrease the production of megakaryoblasts. Another drug you can give is called, interferon alpha and this will work similarly to decrease the number of megakaryoblast that you have. But finally, in emergencies, if you’ve got excess bleeding or the patient is rather unstable, one of the things you can do is a procedure called, platelet phoresis. Platelet phoresis which is similar to dialysis where you filter the blood through a machine but in this case you are filtering the
blood for excess platelets to decrease their risk
of thromboses or bleeding or whatever else it is that
initiated the emergency. Now most cases of
essential thrombocythemia never get to be this bad. Most patients are actually
in this low risk range and are treated on something pretty benign like aspirin but now that we’ve talked about all of these things here, now you’re able to identify, think about how you’d diagnose or what you’d probably do to even treat essential thrombocythemia.

22 Replies to “What is essential thrombocythemia? | Hematologic System Diseases | NCLEX-RN | Khan Academy”

  1. thank you for making this video. I have e.t. …my on-site symptom was a stroke…followed by h.I.t. and when I told someone I have a platelet disorder called e.t. they said…"explain that" haha I can't even say the words…so I'm gonna show them this very well made and informative video.

  2. I have ET with Myelofibrosis. Im a 34 year old Male and just started JAKAFI pills to HELP. SO far I still feel like shit ,but I'm praying something will give. Such a HELPFUL VIDEO.

  3. iron deficiency anemia -> inc EPO -> inc thrombocytes(platelet) but not rbc because not enough iron -> slight thrombocytosis
    must differentiate essential thrombocythemia from IDA

  4. ET different from other myeloprolif because:
    1) No marrow fibrosis
    2) No progress to acute leukemia
    3) No gout because platelets dont have nucleus

  5. I have had ET since 2008. Since turning 40 (43 now) symptoms like night sweats, headaches, feeling sick, tiredness all the time have increased a lot. Was not on anything until now, just aspirin. Have noticed drs are taking more notice (they did before but even more so now) of symptoms. They say it's because I am older. Would not like to get to the stage of non chemo drugs so just take one day at a time but it is really hard emotionally and mentally as your life is totally different and that can be hard to accept. People don't see anything wrong with you and don't understand so I don't explain. There is no energy in me sometimes and can live to sleep and literally take each day as it comes, took a lot of getting used to because I have just done whatever I want.

  6. I just got this diagnosis after bone marrow biopsy Thursday, I don’t think it’s very common. Mine is hemorrhagic type.

  7. I have ET. Platelet count = 1,250,000! I’ve had it for 5 years now. While I was radiation tx for breast ca. Will I ever get AML? I’m on Anagrelide 6 times a day. Tried Hydrea, side affects were horrific! Really bad. Thank you Dr. very informative! Subbed

  8. I still don't get it what's the difference between E.T and PV 🙁 Is it possible to have both?
    Mine is high RBC and platelet as well, but stll waiting for the complete blood test to come out.

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