Polycythemia vera is a condition characterized by an overproduction of red blood cells. What are the causes of this pathology? How to detect and treat it? We take stock.
Hypertrichose, Lafora disease, syndrome de Cushing, progeria… There are several rare diseases. These pathologies are often serious, genetic, orphan, chronic, disabling and sometimes fatal. They are little known to the general public and little studied by the scientific community.
Among rare conditions, we also find polycythemia vera. This pathology affects both men and women. It can occur at any age. However, it most commonly presents between the ages of 50 and 70. According to Orphanet, its incidence is approximately one in 36,000 to one in 100,000 individuals per year. As for its prevalence, it is one in 3,300 patients.
What is polycythemia vera?
Polycythemia vera is also called polycythemia vera. This condition belongs to a group of pathologies called “myeloproliferative syndromes (PMS)”. Myleoproliferative syndromes are tumor diseases of bone marrow. They are presented by an excess production of blood cells.
Polycythemia vera is characterized by an overproduction of Red cells. This excess of red blood cells is “due to an uncontrolled production, often associated with an overproduction of leukocytes and platelets”, specifies Orphanet. The term “polycythemia” means that bone marrow produces an excessive number of red blood cells which then pass through the blood. Polycythemia vera thus originates in the bone marrow.
Erythropoietin (Epo), a hormonal growth factor, controls the production of red blood cells. In the case of polycythemia vera or “primitive”, the hyperproduction of red blood cells is spontaneous but erythropoietin (Epo) does not increase. In contrast, in “secondary” polycythemia, the increase in red blood cells is associated with an increase in hormonal growth factor.
Polycythemia vera: what are the causes?
The exact cause of this condition is not known and determined. However, the majority of people with polycythemia vera have a mutation of the JAK2 gene. This mutation leads to unregulated proliferation cells, called precursors or progenitors, at the origin of red blood cells.
What are the symptoms of polycythemia vera?
Polycythemia vera may have no symptoms in the early stages of the disease. However, signs can occur when a large amount of red blood cells and platelets build up in the blood.
Symptoms of the disease are:
- Visual disturbances
- Aquagenic pruritus, which is itching or tingling after contact with water
- Erythrosis of the skin (on the face and palms), mucous membrane and conjunctival, i.e. permanent redness
Vaquez disease: what are the possible complications?
According to doctors from the French Society of Hematology, polycythemia vera can cause complications when it progresses and if left untreated. Thrombotic complications, i.e. obstruction of one or more blood vessels, can occur. They can cause pulmonary emboli or strokes.
Fibrosis can also appear in the bone marrow. “After many years of development, polycythemia vera can also turn into acute leukemia. These serious and late developments are fortunately very rare”, say the doctors.
Polycythemia vera: how to diagnose it?
To diagnose polycythemia vera, one should perform a blood test. Blood tests show the ratio of the number of red blood cells to the total volume of blood. They thus make it possible to notice an increase in the rates ofhemoglobin and hematocrit.
When the hematocrit level is greater than 52% in men and 48% in women, the amount of red blood cells in the blood is correct. On the other hand, if it is greater than 60% in men and 56% in women, it means that the patient suffers from polycythemia. The diagnosis should be confirmed by clinical examination and ultrasound.
The patient can also take a blood test to identify the mutation in the JAK2 gene. This examination can be performed in hospital laboratories.
How to treat polycythemia vera?
The treatment of polycythemia vera relies on bloodletting. A bloodletting consists of taking blood to reduce the hematocrit level, improve blood flow and reduce the risk of complications. Cytoreduction, i.e. reduction in tumor size, may be considered for patients over 60 years of age, people with vascular disease, d’hypertension or a history of thrombosis. “Hydroxyurea remains the standard treatment for elderly patients”, indicates the Orphanet.
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