What happens to the blood
Normally, the production of red blood cells is regulated by the hormone erythropoietin: its level increases when tissues lack oxygen. In polycythemia vera, the mutant JAK2 protein constantly sends a signal to cells to divide, and production occurs regardless of need. The level of erythropoietin, on the contrary, is reduced. Blood volume and viscosity increase, blood flow in small vessels slows down, and the tendency to form blood clots increases. Overproduction of cells depletes iron stores, so it is not uncommon for red blood cells to become small when their numbers are high.
- JAK2 mutation triggers uncontrolled cell division
- Erythropoietin is decreased, not increased
- Blood viscosity and the volume of circulating red blood cells increase
- White blood cells and platelets are also often elevated
- Iron stores are depleted
- The spleen gradually enlarges
Symptoms
For a long time the disease proceeds hidden. Gradually, headache, heaviness in the head, dizziness, tinnitus, impaired concentration, redness of the face and palms, and redness of the eyes appear. A very characteristic symptom is itching of the skin after a hot shower or bath, which is difficult to explain by anything else. Many people report burning and tingling in their fingertips, sometimes with redness and pain. Due to the enlarged spleen, heaviness in the left hypochondrium and rapid saturation occur. Some patients learn about the disease only after thrombosis.
- Headache, dizziness, tinnitus
- Red face and bloodshot eyes
- Itchy skin after hot water
- Burning and pain in the fingertips
- Heaviness in the left hypochondrium
- High blood pressure
- Nosebleeds and bleeding gums
Diagnostics
They start with distinguishing polycythemia vera from a secondary increase in red blood cells. Secondary erythrocytosis occurs with smoking, chronic lung diseases, sleep apnea, living at high altitudes, kidney tumors and testosterone intake; in these cases, erythropoietin is elevated or normal. In polycythemia vera it is low, and a JAK2 mutation is detected in the blood, which is detected in the vast majority of patients. The picture is completed by bone marrow biopsy and ultrasound of the spleen. Ferritin levels, uric acid levels and kidney function are also checked.
- Complete blood count, hemoglobin and hematocrit over time
- Erythropoietin level
- JAK2 mutation test
- Trephine biopsy of bone marrow
- Ultrasound of the spleen and abdominal organs
- Ferritin, uric acid, creatinine
- Elimination of smoking, apnea and lung diseases
Why is the disease dangerous?
The main threat is thrombosis, both arterial and venous. They determine the prognosis and are the main cause of complications. There is also an increased tendency to bleed, especially with a very high platelet count. Over time, in some patients the disease passes into the phase of hematopoietic depletion with the development of myelofibrosis, and in a small proportion - into acute leukemia. Constant cell breakdown increases uric acid levels, which can lead to gout attacks and kidney stones. Regular monitoring reduces all these risks.
- Myocardial infarction and stroke
- Thrombosis of deep veins and pulmonary artery
- Thrombosis of abdominal vessels
- Bleeding with high thrombocytosis
- Transition to myelofibrosis
- Gout and urolithiasis
Treatment and lifestyle
The goal of treatment is to keep the hematocrit below the target level prescribed by the doctor, thereby reducing the risk of thrombosis. Basic measures are regular bloodletting and low doses of acetylsalicylic acid, unless there are contraindications. For older patients who have had thrombosis or have a high cell count, cytoreductive drugs are added, and if intolerant, interferon or targeted therapy is used. It is important to control blood pressure, cholesterol and weight, stop smoking, and drink enough fluids. Iron supplements for this disease are not prescribed without a doctor's instructions.
- Phlebotomy to maintain target hematocrit
- Low doses of acetylsalicylic acid as prescribed
- Cytoreductive therapy in risk groups
- Interferon or targeted drugs when indicated
- Quitting smoking
- Drinking enough, especially in hot weather
- Control of blood pressure, lipids and body weight
