Essential thrombocythemia is a blood disorder characterized by increased production of platelets. It is genetically determined, according to current evidence. Thrombosis is common.
What is essential thrombocythemia?
Essential thrombocythemia is a myeloproliferative neoplasia (MPN). In this case, there is increased formation of platelets. The term “essential” means that the increased platelet formation is not a concomitant of another blood disorder, but is the primary symptom. Normally, between 150,000 and 450,000 platelets are found in the blood per microliter of blood. If the platelet count rises above 450,000 microliters, the levels are elevated but without symptoms. If the count exceeds 600,000, there may be increased thrombus formation associated with the development of thrombosis and microcirculatory disorders. When the level is above 1000,000 platelets per microliter, instead of thrombosis formation, an increased bleeding tendency comes to the fore. The platelets have the task of sealing the blood vessel in the event of injury by clumping together, forming a blood clot that quickly dissolves after healing. The increased number of platelets can lead to large blood clots that clog vessels. However, even higher platelet concentrations cause absorption of clotting factors, again increasing the tendency to bleed. Women are affected by the disease more often than men. Life expectancy is normal in the mild form of ET.
Causes
Like all myeloproliferative neoplasms, essential thrombocythemia is genetic. However, despite genetic predisposition, the disease does not occur in every patient. The severity of the disease also varies among individuals. The genetic background has not yet been fully elucidated. In recent years, however, three different mutations have been identified for this disease. Half of all cases have a mutation in the tyrosine kinase JAK2. This is the JAK2 mutation-V617F. In this mutation, the JAK2 tyrosine kinase remains permanently active and causes the constant production of platelets. However, JAK2 mutation-V617F has been found to exist in other MPNs such as polycythemia vera and osteomyelofibrosis. In one percent of cases, there is a mutation in the gene encoding the thrombopoietin receptor MPL. This permanently stimulates the blood stem cells in question to grow. In 70 percent of all diseases without JAK2 mutation-V617F, the gene CALR, which encodes the protein calreticulin, is altered. Interestingly, the JAK2, MPL and CALR mutations never occur together. Thus, it can be assumed that at least three different mutations must be responsible for the same clinical picture.
Symptoms, complaints, and signs
Essential thrombocythemia occurs in three different forms. The development of disease symptoms is largely dependent on the concentration of platelets. In many cases, the disease is asymptomatic. When symptoms do occur, they are usually microcirculatory disturbances with increased blood pressure or functional disturbances. Complications may include thrombosis, myocardial infarction, stroke, or embolism. In an embolism, a blood clot breaks loose and blocks the corresponding blood vessel. On the other hand, deficiency of blood flow can also occur in various parts of the body, such as the legs or the head (empty head). In this case, severe pain occurs in the legs when walking, for example. If the platelet count has risen above one million per microliter of blood, there is again an increased tendency to bleed. One-third of patients do not experience any symptoms. The average life expectancy in these cases is that of the normal population.
Diagnosis
Today, the diagnosis of essential thrombocythemia is usually made during a routine physical examination because the disease is often asymptomatic. Elevated platelet counts are detected. The cause of the elevated values must then be clarified further. This is because high platelet concentrations can also occur in many other diseases. These include iron deficiency, infections or certain tumors. Various criteria must be present for the clear identification of an ET.The platelet count is persistently above 600,000 per microliter. Bone marrow histology reveals enlarged, mature megakaryocytes. Furthermore, the typical mutations for ET must be diagnosed. Because a JAK2 mutation is also present in other MPNs, several other blood disorders must also be excluded.
Complications
In essential thrombocythemia, increased platelet production occurs in the blood. As a result, there is a risk of impaired blood flow. The result is an increased tendency of the blood to clot, which can lead to serious complications. Local blood clotting repeatedly occurs, leading to the formation of a blood clot (thrombus). Both the venous and arterial blood systems can be affected. In ET, there is a particular risk of thrombosis of the deep veins of the leg (phlebothrombosis), the hepatic veins (Budd-Chiari syndrome), and the abdominal veins, especially the portal vein. A feared complication is thromboembolism, in which a thrombus is carried away by the bloodstream and occludes a vessel part or branch. If the venous system is affected, pulmonary embolism may result. The consequences of arterial thromboembolism include the threat of splenic infarction, heart attack and stroke. Microemboli in the brain can lead to a transient ischemic attack (TIA) with transient symptoms resembling a stroke. The duration of the neurological disturbance is usually limited to one to two hours. In addition, essential thrombocythemia may progress to another disease from the group of myeloproliferative neoplasms. In most cases, myelofibrosis or polycythaemia vera develops. The development of acute myeloid leukemia is very rare.
When should you see a doctor?
A doctor must always be consulted for this disease. This will prevent serious complications, which in the worst case can lead to death. A doctor should always be consulted if the affected person suffers from elevated blood pressure over a long period of time. This can also lead to the formation of thromboses on the body. A stroke or heart attack can also occur as a result of the condition. Should this occur, an emergency physician must be notified immediately. Furthermore, mouth-to-mouth resuscitation and cardiac massage must be performed until the emergency physician arrives. The affected person should be placed in a stable lateral position, if this is possible. Similarly, a visit to the doctor is necessary if the patient suffers from circulatory disorders, which can usually be manifested by disturbances in sensibility or paralysis. If the condition does not cause discomfort or symptoms, treatment is usually not necessary. The diagnosis can be made by a general practitioner. However, further treatment depends strongly on the underlying disease and is carried out by a specialist. In most cases, this does not result in a reduced life expectancy for the patient.
Treatment and therapy
Treatment of essential thrombocythemia depends on the severity of the disease. High-risk patients with platelet counts greater than 1500,000 per microliter or a tendency to severe thrombosis or bleeding must always be treated with chemotherapy with hydroxycarbamide, anagrelide, or alpha-interferon. Anagrelide inhibits the growth of megakaryocytes in the bone marrow. The drugs hydroxycarbamide or alpha-interferon suppress the constant formation of platelets. Which drug to use must be decided on a case-by-case basis. A medium risk is present if cardiovascular diseases of other etiology, diabetes mellitus or hypercholesterolemia are already present. Chemotherapy should be weighed up individually here, taking into account the advantages and disadvantages. Possibly, the blood thinner acetylsalicylic acid can be used in low dosage. If the platelet count is less than 1500,000 per microliter, the patient is under 60 years of age, and there are no or only minor symptoms, therapy is limited to regular exercise, weight reduction, avoidance of prolonged sitting and dehydration, and observation of early symptoms of thrombosis.
Outlook and prognosis
Essential thrombocythemia is not curable. The cause of the disease is based on a mutation in the genes.Human genetics may not be altered by scientists and physicians due to legal requirements. Therefore, treatment can only be symptomatic. As soon as the therapy is discontinued, the symptoms immediately reappear. Due to this situation, long-term therapy is necessary to improve health. If left untreated, the patient is at risk of developing a thrombus. This poses a potential threat to life. The prognosis also depends on the severity of the disease. In mild cases, medication is administered. These monitor and regulate the formation of blood cells. The symptoms are alleviated. In regular control examinations the effectiveness of the preparations is checked. In severe cases, treatment with chemotherapy is indicated. This is associated with various side effects. The quality of life is impaired and everyday obligations can often not be fulfilled. Nevertheless, according to current medical knowledge, this is the only way to prolong life. In order to reduce the side effects of the treatment, the affected person should pay attention to a healthy lifestyle. Prolonged sitting should be avoided, a balanced diet supports the organism, and fluids should be taken in at a sufficient level.
Prevention
In general, essential thrombocythemia cannot be prevented because it is genetic. To prevent the onset of symptoms in low-risk patients, a healthy lifestyle with plenty of exercise, a healthy diet, and adequate hydration is recommended.
Follow-up
The person affected by this disease has very limited options or measures of aftercare available in some cases. First and foremost, the disease must be detected and treated early to prevent other complications or symptoms from occurring. Only if treatment is initiated at an early stage can a cure be achieved. However, since the disease is genetic, only purely symptomatic treatment can be carried out. If the affected person wishes to have children, genetic counseling can also be performed. This may prevent the disease from being passed on to descendants. Self-cure does not occur with this disease. Since this disease can very often lead to the development of thrombosis, regular examinations by a physician should be performed. Measures of precaution against cancer should also be taken, so that tumors can be detected and removed at an early stage. In general, a healthy lifestyle with a healthy diet has a positive effect on the further course of this disease. In many cases, however, despite treatment, the life expectancy of the person affected by this disease is reduced. Further aftercare measures are not available to the affected person.
What you can do yourself
Patients with essential thrombocythemia should maintain a balanced and healthy diet to maintain their health. Self-weight should be within the normal range according to BMI guidelines. Overweight should be avoided. A diet rich in vitamins and containing plenty of iron is recommended. In addition, the intake of the recommended daily amount of fluid should be observed, as the body must be protected from dehydration. In addition, to improve health, sufficient movements, long walks and regular practice of sports help. When choosing sports, it is important that a holistic activity takes place and that the body is not overloaded. Sports such as swimming or jogging are advisable. These stimulate the cardiovascular system, but do not overstrain the organism. Rigid postures or prolonged periods of sitting or standing should always be avoided. In everyday life, the body position should be changed at regular intervals. Slight loosening up can be exercised by stretching movements. The circulation can be stimulated with a few counter or compensatory movements. The consumption of stimulants such as nicotine or alcohol should be avoided. It is helpful to attend regular check-ups. The older the patient, the shorter the intervals should be.
