In about two thirds of the individuals, the disease does not cause any symptoms and is diagnosed incidentally on routine blood tests. In patients with symptomatic disease the signs and symptoms vary among different individuals. The most common manifestations are abnormal bleeding or thrombosis.

Bleeding tendency may manifest in the form of:

• Bleeding from respiratory tract.
• Bleeding from gastrointestinal tract.
• Bleeding from urinary tract.
• Bleeding from gums.
• Epistaxis.
• Early bruising.

Thrombi may form anywhere in the body including the heart and intestine, thus compromising their blood supply. Thrombosis occurring in small vessels mainly causes numbness and abnormal burning sensations of hands and feet [5] [6].

Other signs and symptoms of clotting include:

• Changes in speech and orientation causing confusion.
• Seizures.
• Shortness of breath.
• Nausea.
• Discomfort in arms, legs, back, neck, jaw or abdomen.

In high risk cases clotting in the brain may result in stroke. In pregnant females, blood clots in the placenta may cause problems in the fetal growth and development or may lead to termination of pregnancy. All the females with essential thrombocythemia who use oral contraceptive pills are at a higher risk of developing thrombosis.

Most of the cases of essential thrombocythemia are diagnosed during routine blood tests. In patients with the signs and symptoms of platelet dysfunction or thrombocytosis, the diagnosis of primary thrombocythemia is established after ruling out all the causes of these abnormalities.

In order to confirm the diagnosis, a number of different tests are required. These include the following [7].

• Complete blood count: The blood count will show increased numbers of platelets greater than 600,000 per micro liter of blood.
• Blood smear: Blood smear will show abnormally large or clumped platelets.
• Genetic testing: This is done to look for JAK2 kinase mutation.
• Bone marrow aspiration: This will show abnormal megakaryocytes.
• Bone marrow biopsy: Bone marrow biopsy is required to confirm the results of bone marrow aspiration.

Most of the patients with primary thrombocythemia do not need any treatment.

In individuals who are at a higher risk of developing thrombosis or abnormal bleeding, the mainstay of treatment is to lower the platelet count [8]. The most widely used drugs for this purpose are hydroxyurea, interferon-alpha or anagrelide along with low doses of aspirin. These medications are to be taken for whole life [9].

In pregnant and lactating patients, hydroxyurea and anagrelide are contraindicated. These females are monitored closely throughout pregnancy to detect any blood clots. After parturition, these patients receive injections of low molecular weight heparin daily for several weeks as during this time they are more prone to develop thrombosis.

In rare cases with life threatening complications, platelet count can be rapidly reduced by removing platelets directly from blood in a procedure referred to as platelet apheresis.

The outlook for the disease may vary from one patient to another. Most of the patients, if diagnosed and treated properly, may have a normal life span [10].

In a small number of people, complications from bleeding or blood clotting may arise. Rarely, the disease may have the following complications:

• Acute leukemia or myelofibrosis
• Severe bleeding
• Stroke
• Myocardial infarction

There is no definite cause of essential thrombocythemia or other myeloproliferative disorders; however, certain gene mutations in the JAK2 kinase, a member of the Janus-kinase family of genes, have been found in half of the patients with this disorder [3] [4].

Essential thrombocythemia is not a very common disease. The annual incidence rate of essential thrombocythemia is about 2 to 3 per 100, 000 individuals.

The average age at diagnosis is around 40 to 50 years, although it may occur in females below 40 years of age [1]. Very rarely, it can also occur in children and young adults [2].

The bone marrow contains stem cells that develop into different blood cell lineages. Platelets are produced from large cells called megakaryocytes. The normal platelet count ranges from 150,000 to 300,000 per microliter of blood. The main function of platelets is to help in hemostasis by forming a platelet plug at the site of bleeding.

In essential thrombocythemia, there is an increase in the number of platelets in the blood. Besides, these extra platelets do not function normally. In about 50 percent of the patients, this abnormality occurs due to a mutation in the JAK2 kinase which renders the megakaryocytes excessively sensitive to stimulation by the growth factors.

These abnormally functioning thrombocytes may cause episodes of bleeding from different sites in the body or they may cause the formation of blood clots restricting blood flow to the vital organs.

There are no guidelines for prevention of essential thrombocythemia.

Essential thrombocythemia or essential thrombocytosis (ET) is an uncommon chronic hematologic disorder in which megakaryocytes in the bone marrow produce excessive platelets (thrombocytes) without any known cause. It is also known as primary thrombocythemia (PT). 

Essential thrombocythemia is one of the four components of a group of conditions called myeloproliferative disorders; the other three members of this group being chronic myelogenous leukemia, polycythemia vera and primary myelofibrosis.

It is primarily a disease of platelets but rarely other cell lineages such as red blood cells and white blood cells are also produced excessively. Essential thrombocythemia mostly occurs in people of the age of 40 to 50 years.

Most common presentations include abnormal bleeding (from the respiratory system, gastrointestinal system and skin), thrombosis, headache, dizziness and abnormal sensations in hands and feet.

The condition needs no treatment if it is symptomless; however, in case of symptomatic disease, platelet-lowering drugs are used along with small doses of aspirin to control thrombotic events.

In patients with proper treatment, the life expectancy is the same as that of a person who is not suffering from this condition.

Essential thrombocythemia is a rare, slowly progressive disease of blood in which a large number of abnormal platelets are produced. These platelets cause abnormal blood clotting or bleeding episodes in the persons suffering from this disorder.

The patients may complain of nose bleeds, blood in stools, early bruising, prolonged bleeding from cuts or other injuries, burning or tingling sensations in palms and soles of the hands and feet respectively.

In some cases, blood clots in large vessels may result in brain stroke or heart attack. In pregnant females, this condition may cause miscarriages.

The disease is treated with medicines which lower the number of platelets and the overall prognosis is good with a normal life expectancy.

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