Why does the plasma volume go up in polycythemia vera?
Q. Why does PV, plasma volume, rise in polycythemia vera? This seems counterintuitive. (more…)
Q. Why does PV, plasma volume, rise in polycythemia vera? This seems counterintuitive. (more…)
Q. If the chronic leukemias have lots of mature cells, and the acute leukemias have immature cells, then how come chronic myeloid leukemia has lots of immature cells? Seems like it belongs in the acute leukemia category! (more…)
Q. I was wondering what the difference was between labeling something as a “leukemia” vs labeling it as a “chronic myeloproliferative disorder.” (more…)
Here are some real student questions about myeloproliferative disorders. You should always ask questions when you don’t understand something – preferably in lecture. (more…)
What if you had a blood smear in which you thought the diagnosis was chronic myeloid leukemia (CML), but you didn’t have access to a cytogenetic or molecular lab (to look for the Philadelphia chromosome or the bcr-abl translocation)? (more…)
Many hematopoietic malignancies have characteristic cytogenetic changes, such as translocations or inversions. It’s important to know about these because they can be used for diagnosis in tough cases, and they often carry a prognostic significance. (more…)
The four main myeloproliferative disorders share several similarities such as a hypercellular marrow, a high white count with a left shift, and splenomegaly. (more…)
There are four major types of myeloproliferative disorders: chronic myeloid leukemia, chronic myelofibrosis, polycythemia vera, and essential thrombocythemia. (more…)
We’ve talked already about how you’d differentiate chronic lymphocytic leukemia from a benign lymphocytosis. So how about the same thing for the myeloid series, namely, how do you tell apart chronic myeloid leukemia from a benign neutrophilia? (more…)
Polycythemia vera (PV) is a chronic myeloproliferative disorder in which the red cells are the predominant lineage. Here are some typical student questions along with my answers.
Q.Are the erythrocytes in PV normal?
A. No, they aren’t considered normal because they come from a malignant clone of erythroblasts. But they do carry oxygen, and they do act and look like benign RBCs. They’re just the end stage of a malignant erythroblast’s development.
Q. How come the oxygen saturation is normal in PV?
A. You use the oxygen saturation to tell apart primary polycythemia (polycythemia vera) from secondary polycythemia. In secondary polycythemia, the oxygen saturation is usually low (that’s why the patient is making so many red cells – he or she needs to create more oxygen carrying capacity! Maybe the patient lives way up in the mountains or something.). In contrast, the oxygen saturation is normal in polycythemia vera, because the malignant RBCs are simply carrying the oxygen that happens to be around (and they carry it the same way benign RBCs do), and unless the person with polycythemia vera happens to live way up in the mountains and smoke (pretty unlikely), the oxygen saturation in that person should be normal.
Q. Does the test for RBC mass necessarily tell you whether the red cells are benign?
A. The test for RBC mass and the plain old red blood cell count (RBC) that you get in a CBC do not differentiate between benign mature red cells and the malignant mature red cells you see in polycythemia vera. So patients with any kind of polycythemia (whether it’s primary or secondary) will have an increased RBC mass/increased RBC.
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