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- Wed Jul 28, 2010 9:25 pm
I am a 43 yo femalie with mild hypertenstion 130/90. I do not smoke and have never smoked. I have no history of Lung or Heart Disease. I have a history of oncology visits 2 years ago. I had high hematocrit, hemoglobin and RBC. I believe my EPO was low at that time. I had a bone marrow aspiration/biopsy and it came back normal. I then lost my insurance. I have had no care for 2.5 years but am finally insured again.
My first CBC came back
I went to the lab today and had blood drawn for a JAK 2 mutation test. I am not able to see the oncologist for 3 weeks. I am feeling very anxious about it all.
I would really appreciate any input. Thank you so much for this service!!
| Dr.M.Aroon kamath
- Fri Jul 30, 2010 3:42 am
Philadelphia chromosome is a choromosomal abnormality seen in 95% of cases of chronic myelogenous leukemia (CML). It is a reciprocal translocation (swap of chromosomal material) between chromosomes 9 and 22. Thus, Philadelphia chromosome is a BCR-ABL fusion gene.
BCR stands for "breakpoint cluster region" gene from chromosome 22. ABL stands for ‘Abelson murine leukemia viral oncogene homolog’ from chromosome 9.
There are 4 myeloproliferative disorders. These may be classified into two major groups.
- BCR-ABL mutation positive: Chronic myelogenous leukemia and
- BCR-ABL mutation negative: Essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia (the "classic" BCR-ABL -negative myeloproliferative disorders).
(BCR-ABL mutation positive cases of Essential thrombocythemia have been repoted fairly recently).
Each of these MPDs is believed to represent a stem cell-derived clonal myeloproliferation with the features of thrombocytosis, erythrocytosis, and bone marrow fibrosis respectively.
Unlike with cases of chronic myeloid leukemia, in which the bcr/abl mutation is invariably detectable, current diagnosis of essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia is based on a set of clinical and laboratory criteria that have undergone substantial modification in recent times.
A unique “gain-of-function” mutation, Janus tyrosine kinase (JAK2), was first reported in 2005 in PV. Since then it has been identified in all 3 classic MPDs.
Polycythemia Vera (PV): in PV, a reported increase in hematocrit (Hct) value
may or may not represent a true increase in erythrocyte production.
Apparent polycythemia: results from either an acute plasma contraction
(relative polycythemia) or confusion regarding the upper limit of normal laboratory values for Hct.
Although acute plasma contraction is a well accepted entity, the existence of chronic plasma contraction, [Gaisböck syndrome (relative polycythemia with nephropathy & hypertension) as well as “stress polycythemia” (relative polycythemia occurring with emotional stress)] is still debated.
Traditionally, PV has been diagnosed based on the criteria from the ‘Polycythemia Vera Study Group’, which requires an elevated red blood cell mass.
Some clinicians currently recommend that one should depend primarily on the clinical presentation, serum erythropoietin (sEPO) level, and bone marrow histology in diagnosing PV.
Initial work-up: includes determination of the sEPO level and further investigations are based on this value.
In PV, the sEPO level is usually low but can be normal; It is extremely unlikely to be elevated. Therefore, further work-up is recommended only if the sEPO level is low or normal.
A low sEPO level mandates a BM biopsy to look for morphologic evidence of PV as well as to test for JAK2 mutation.
Decisions to perform BM biopsy and JAK2 mutation screening, in cases with normal sEPO levels, should be based on the presence or absence of a compelling clinical picture (pruritus, erythromelalgia, splenomegaly, arterial or venous thrombosis) or laboratory (thrombocytosis, leukocytosis, increased leukocyte alkaline phosphatase score, well documented increase in Hct level from an individual’s baseline value).If these features are lacking, then, one should consider close follow up with periodic monitoring of Hct and sEPO levels.Abdominal ultrasonography to exclude splenomegaly may be useful.
As you may well appreciate, in your case, one may not diagnose PV based on the elevated Hct alone, but the sEPO level will perhaps determine the further workup needed. So, you need to be patient till then.
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