Polycythemia Vera(TE)

La polyglobulie de Vaquez

 

icn_gene  General:

Also called primary polycythemia, or called Vaquez Disease after person who first described the disease in 1892.

Impact: Between 10 and 15 cases per 1 million persons.

Classified as rare disease.

 

icn_sym  Symptoms:

The proliferation of erythrocytes (synonym: red blood cells or RBC) causes a thickening of the blood. Many of the symptoms are:

  • Erythromelalgia, resulting in red patches on the hands, toes or face.
  • The feeling of high head temperature is significant.
  • TIAs (Passing ischemic accident) is among one of the first alerts or symptoms, also more major vascular events, particularly portal vein thrombosis which develops with serious effects in Budd-Chiari syndrome.
  • Headaches are often reported. Hypertension (HTN) can also reported in accompaniment to the headaches.

The chance of discovery at a CBC (Complete Blood Count) is becoming more common.

 

icn_diag  The diagnosis:

The diagnosis must always be done by a haematologist.

The first phase of diagnosis is always a blood count. It would show an increase in level of haemoglobin (>16 for a man, >15 for a woman) and an elevated hematocrite, indicating the percentage of red cells in the blood (50 and over). These are the only parameters that can used be present figures above normal, but often these symptoms are accompanied by a elevation in platelet count (> 400,000) that can vary in significance. A rise in the rate of Neutrophil Granulocyte during a transitional period can also be observed on occasions.

The second examination done from a blood test is looking for the JK2V617F mutation. This is present in 95% of Polycythemia Vera disease and confirms the diagnosis of a MPN (Myeloproliferative Neoplasms). Polycythemia Vera is said to be identified, when the possibility of any another diseases has been ruled out.

Further investigation may be necessary; in particular the measurement of the blood volume, against the typical blood volume characteristic associated with Polycythemia. A bone marrow examination may also be required when the diagnosis is uncertain. Moderate splenomegaly (enlarged spleen: from 12 to 15 cm) is sometimes observed.

 

icn_trait  Treatments:

In an emergency, when the blood count numbers are particularly high, the first line of treatment is a phlebotomy (bleeding, or the removal of blood). This practice, very similar to what is practiced for blood donors, consist in removing 350-500 g of blood to reduce the concentration of erythrocytes and thus relieve the patient. This method has long been the only treatment for the disease. This is practiced today only in the case of an emergency upon the discovery of the disease, or to compliment to another treatment whose effectiveness is delayed.

Bleeding (phlebotomy), is not strictly speaking a treatment, and so does not induce any side effects. However, it is an onerous method that forces the patient to travel frequently to a blood clinic. Furthermore, blood volume restores quickly, resulting in the CBC having a “saw tooth” pattern which is not ideal. It also evokes a ripple effect where the bone marrow would automatically be “prompted” to produce more red blood cells.

The first line of chemical treatment remains at present to be Hydroxyurea (Hydrea). Having perfectly manageable side effects (see the product’s instructions) this medication often gives good results to significantly reduce the rate of erythrocytes in the blood. A serious drawback however is that treated men become sterile with hydroxyurea, often outright. It would be prudent before starting a hydroxyurea treatment to freeze sperm for the future. If the results are not effective over time, other medications are used, such as:

  • Pegylated interferon (or α2A α2B): Used much more delicately as the side effects are more difficult to control (refer to the product’s instructions). Severe fatigue may occur along with unexplained pain. Pegylated interferon reduces the rate of the mutated kinase JK2V617F. However, there is a great difficulty when starting this treatment, as it may be necessary to vary the dosage for several months before finding the correct dosage. Many patients resent and get tired of the side effects, and often give up on the treatment before identifying the right dosage.
  • Pipobroman (Vercyte) still preferred by some doctors. This is an alkylating, whose long-term effect results in acute leukemia, thus discouraging its use. The manufacturing of this product was stopped in 2014 and resumed in 2015.The anti-JAK2, with the exception of JAKAVI ( ruxolitinib), are still in the evaluation phase. They will begin to be applied to the treatment of Polycythemia Vera in the experimental phase. It is currently too early to give an evaluation on these products. With the current test dosages, the side effects appear to be difficult to control. The ruxolitinib gives interesting results. It has obtained a marketing authorization

Polycythemia Vera and Pregnancy:

It may seem to be a contradiction, but even in the most serious cases of Polycythemia Vera, it is still possible. It is recommended to seek medical advice from a haematologist before trying to conceive and to respect the guidelines that are to be followed once provided. These are still pregnancies which are ‘at risk’, and which require special precautions.

 

icn_prono  Prognosis:

Polycythemia Vera is a chronic disease whose progress is not predictable. Life expectancy may not change, but a shift to a more severe form is to be feared. In this case, the progression is to myelofibrosis. A progression towards Acute Myeloid Leukaemia (AML) can happen directly or following the progression of myelofibrosis. Some deaths occur, although thankfully rare, remain unexplained and are difficult to interpret even after clinical investigation.

 

icn_evol  Criteria of evolution:

Biologically, a steady decline in platelet and red blood cell count; with or without the presence of blasts, unexplained weight loss, should prompt review of the diagnosis. Clinically, increased fatigue, night sweats, mild fever are all clear signs.

A key criterion of the diseases progression remains increased and unexplained tired.

Date de l’artcle : 25/10/2012