Essential Thrombocythemia: Causes, Symptoms, Treatment, Life Expectancy, Prognosis, Diagnosis

Essential thrombocythemia is a rare and chronic condition where there is excessive production of blood platelets in the body. Due to this condition, patient experiences tiredness, lightheadedness, headaches and changes in vision. Essential thrombocythemia also increases the risk of blood clots. Individuals aged over 50 years commonly have this condition; however, it can develop at any age. Women are at a slightly increased risk for Essential Thrombocythemia than men.

There is no cure for Essential Thrombocythemia. Treatment is not needed if this condition is in mild form. In severe cases of Essential Thrombocythemia, medicines are given to lower the platelet count along with blood thinners.

Our bones contain a spongy tissue known as bone marrow that contains stem cells which is responsible for producing red blood cells, white blood cells and thrombocytes (platelets). Platelets are responsible for clot formation and they do this by sticking to each other and help in stopping the bleeding when there is any damage to a blood vessel. The normal range for platelet count is about 150,000 to 450,000 platelets per microliter of blood.

In cases of essential thrombocythemia or primary thrombocythemia, there is overproduction of platelet-forming cells, i.e. megakaryocytes by the bone marrow. These extra platelets do not function properly and result in abnormal bleeding or clotting.

The exact cause of essential thrombocythemia is not known. Around 80% patients with this condition will have an acquired gene mutation, which contributes to essential thrombocythemia. This can involve the calreticulin (CALR) or MPL and Janus kinase 2 (JAK2) gene mutation.

An increased platelet count resulting from iron deficiency or an underlying medical condition, such as infection, is called secondary or reactive thrombocythemia. Patients suffering from secondary thrombocythemia are at a lesser risk of bleeding and blood clots than patients having essential thrombocythemia.

Older individuals having Essential Thrombocythemia and individuals who have experienced prior bleeding or blood clots problems are at a greater risk for complications. Some of the potentially serious complications occurring as a result of abnormal blood clotting in essential thrombocythemia include:

• Complications in pregnancy can occur. There are many women, who although suffering from thrombocythemia, will have normal and healthy pregnancies. However, uncontrolled thrombocythemia can result in miscarriage along with other complications. Medications and regular checkups help in reducing the risk of complications in pregnancy from essential thrombocythemia.
• Stroke can occur in patients suffering from essential thrombocythemia. Formation of a clot, which obstructs blood flow to the brain causes stroke.
• Heart attack can occur when the clot blocks the blood circulation to the heart. Symptoms of heart attack include fullness, pressure or squeezing pain in the middle of the chest, pain radiating to the arm, shoulder, back, jaw or teeth, clammy skin, sweating and shortness of breath. Immediate medical attention should be sought if anyone experiences the above symptoms.
• Patient can also experience bleeding with significant blood loss in essential thrombocythemia. In some cases, essential thrombocythemia can progress to some fatal diseases, such as: Myelofibrosis and Acute Myelogenous Leukemia. Myelofibrosis is a disorder of the bone marrow causing bone marrow scarring, severe anemia and spleen and liver enlargement. Acute Myelogenous Leukemia is a form of bone marrow and white blood cell cancer, which advances very rapidly.

Development of a thrombus or a blood clot is the first sign of Essential Thrombocythemia. Signs and symptoms depend on the site of clot formation. Clots can form anywhere in the body, but in case of essential thrombocythemia, clots commonly develop in the brain, hands and feet. Common signs & symptoms of Essential Thrombocythemia are:

• Lightheadedness or dizziness.
• Headache.
• Weakness.
• Chest pain.
• Fainting.
• Changes in vision, which are temporary.
• Tingling or numbness in the hands and feet.
• Erythromelalgia, i.e. burning pain, throbbing and redness in the hands and feet.
• Slight enlargement of the spleen.

Patients with essential thrombocythemia may also have bleeding; especially if the platelet count is very high; although this is uncommon. Bleeding can occur in the form of:

• Bruising.
• Nosebleeds.
• Bleeding from the gums or mouth.
• Bleeding in stools.

If there is blood clot in the arteries, which supply the brain, then it can cause a stroke or transient ischemic attack (TIA). Signs and symptoms of a TIA or stroke are sudden and include:

• Aphasia, which is difficulty in speaking or understanding speech.
• Numbness or weakness in the face, arm or leg, often experienced on one side of the body.
• Vision changes, which include double, blurred or decreased vision.

If the platelet count is more than 450,000 platelets per microliter of blood, then the doctor will try to find out the underlying medical condition causing this. Other causes of high platelet counts are excluded to confirm the diagnosis of essential thrombocythemia. Blood tests are done which include:

• Complete blood count (CBC) to find out the number of platelets in the blood.
• Blood smear, where a small amount of blood is taken on a slide and is examined under a microscope to assess the activity and size of the platelets.
• Genetic testing is done to determine if there are any chromosomal abnormalities, which are causing the increased platelet count. Genetic testing also helps in finding out whether there is mutation in the JAK2, CALR or MPL gene.
• Blood test is also done to check the iron level in the blood or to look for markers of inflammation.
• Bone marrow aspiration or bone marrow biopsy is done where a small amount of the liquid bone marrow or a sample of solid bone marrow tissue is taken through a needle. This sample is then sent to a laboratory to be examined under a microscope to find out if the bone marrow contains an increased amount of megakaryocytes, which are the cells responsible for producing platelets.

Treatment for Essential Thrombocythemia depends on the patient’s risk of bleeding episodes or blood-clotting. If the patient is younger than 50 and does not have any signs or symptoms of Essential Thrombocythemia, then regular medical checkups will suffice. Medications to treat Essential Thrombocythemia are prescribed if the patient is:

• Greater than 50 years of age.
• If the patient has had a previous history of blood clots or TIAs.
• If the patient has cardiovascular risk factors, such as hypertension, high cholesterol and diabetes.

The following medications can be prescribed to decrease the clotting risk or platelet count in a patient.

• Low-dose aspirin is prescribed in essential thrombocythemia, as aspirin helps in making the platelets less sticky and thus decreases the chances of formation of blood clots. Aspirin is more commonly used in pregnancy, as it carries fewer side effects for the fetus.
• Hydroxyurea is a medication, which suppresses the production of blood cells by the bone marrow, including the platelets. It has mild side effects and the patient’s blood counts and liver function will be monitored while on this medication. It is thought that long-term use of this medication can slightly increase the chances of developing acute myelogenous leukemia.
• Anagrelide is another medication for treating essential thrombocythemia. It is not thought to increase the risk of leukemia, but is also not considered as effective as Hydroxyurea. Side effects of Anagrelide include heart problems, fluid retention, headaches, nausea, dizziness and diarrhea.
• Interferon Alfa or Pegylated Interferon alpha 2a is a medicine, which is given via injection. This treatment is more expensive and has worse side effects than anagrelide and hydroxyurea; however, it can be the best treatment choice for some people. Side effects of this medicine include confusion, flu-like symptoms, nausea, diarrhea, depression, irritability, seizures and sleepiness.

Plateletpheresis is a medical procedure, which is used only in emergency situations, such as after the patient has experienced dangerous blood clotting or a stroke. This procedure works by temporarily lowering the platelet count. A needle is attached to a tube through which the blood flows to a device that removes the platelets, after which the blood is transfused back to the body with a decreased platelet count.

Adopting a healthy lifestyle habits lowers the risk of developing conditions, such as hypertension, diabetes and high blood cholesterol, which can contribute to blood clotting. The following measures should be undertaken:

• Eating a healthy diet comprising of vegetables, whole grains and fruits with very few saturated fats should be followed. Trans fats should be avoided and portion control should be developed to maintain a healthy weight.
• Quit smoking and alcohol for a healthy life and to fight essential thrombocythemia more effectively.
• It is important to exercise or partake in some sort of physical activity, such as brisk walking, swimming or riding a bicycle, for a minimum of 30 minutes a day.
• Lose weight if you are overweight, as obesity increases the venous pressure in the pelvis and legs. Being overweight also increases the risk for high blood pressure and diabetes.

If Essential Thrombocythemia is diagnosed and treated on time, then the prognosis is good and patients have an excellent chance of living a long life, i.e. they have a very good chance of having a normal life expectancy. Essential Thrombocythemia is a chronic condition and it is important that the patients are monitored regularly and should consult their physician if they are experiencing any symptoms, such as unexplained pain, visual disturbances, tingling or numbness and bruising. If the patients do not have any symptoms, then treatment is not needed and they are monitored on a regular basis. If the patients experience symptoms, then treatment is required.

About less than 10 to 15% of patients having Essential Thrombocythemia can develop acute leukemia or post-polycythemic myelofibrosis later on in their lives. Both of these conditions can be potentially life threatening.