Polycythaemia Vera (PV) is a Rare Disease of the blood-building cells in the bone marrow primarily resulting in a chronic increase of red blood cells (erythrocytes), thereby decreasing the flowability of blood. Circulatory disorders such as thrombosis and embolism are possible consequences.
With proper treatment, the majority of patients with Polycythaemia Vera have a near-normal life expectancy.
The cause of Polycythaemia Vera is still unknown. The disorder is usually contracted but, in rare cases, it can be inherited. It is typically characterized by an increase in the production of red blood cells (erythrocytes). Patients with PV are often symptom-free at the time of diagnosis.
At the onset of the disorder, the signs and symptoms tend to be unspecific. A noticeable reddening of the face can give the impression that the affected person is actually very healthy. When the red blood cell count reaches a critical number, the flowability of the blood decreases leading to restricted blood circulation. This causes a blue coloration of the skin (cyanosis).
Other symptoms may include:
The most common complications are a result of the high viscosity (resistance to flow) of the blood, which can lead to blood clots (thrombosis). Clogging of both small and large blood vessels (embolism) can also occur.
Both the number of platelets and their function are responsible for the balance of the coagulation system. Hypercoagulation results in blood clotting, while lack of coagulation results in bleeding (e.g. skin, gastrointestinal tract).
The patient will be referred to a specialist (hematologist) for further examination if Polycythaemia Vera is suspected (due to unspecified symptoms and a change in the blood count such as an increase in hemoglobin or hematocrit).
During the diagnosis it is important to first check if the increase in erythrocytes does not stem from a reactive condition caused by an underlying disease. Hence, underlying conditions in the heart, lungs, liver or kidney need to be ruled out as possible causes.
The number of erythrocytes, together with the hemoglobin and hematocrit results, are elevated (hemoglobin: blood pigment, hematocrit: cellular components of blood).
An increase in thrombocytes and leucocytes also points to the existence of PV.
95% of all PV patients are carriers of the JAK2V617F mutation.
If the kidneys suffer from a lack of oxygen, they release erythropoietin which stimulates the production of blood cells in the bone marrow (erythropoiesis). However, in the case of Polycythaemia Vera, a rise in the erythrocyte count provides the organ with a higher amount of oxygen, which leads to a decline in the production of erythropoietin.
The upper abdomen should undergo an ultrasound scan in order to check the size of the liver and spleen. These organs are sometimes swollen in patients with Polycythaemia Vera.
The removal and histological examination of bone marrow from the iliac crest region may provide verification in uncertain cases.