Essential thrombocythemia

Overview

Essential thrombocythemia, also known as primary thrombocythemia, is a rare blood disease characterized by an overproduction of platelets in the bone marrow. The excessive number of platelets increases the risk of thrombus formation, which can lead to severe health issues such as stroke, heart attack, or pulmonary embolism. Platelets play a crucial role in clotting blood to prevent excessive bleeding. Essential thrombocythemia is considered an acquired genetic condition, meaning it occurs when specific genes undergo mutations or changes.

The condition is often detected during a routine blood test, which reveals abnormally high platelet levels. In some cases, individuals may not initially experience any symptoms, and immediate treatment may not be necessary. Although essential thrombocythemia is not curable, appropriate treatment strategies can help reduce the risk of developing serious complications.

The main objective of treating essential thrombocythemia is to minimize the likelihood of thrombotic events. The approach to treatment varies based on individual factors, and for those without symptoms, a strategy known as watchful waiting may be recommended. Medications aimed at preventing blood clots and reducing platelet levels are commonly prescribed by healthcare providers to manage essential thrombocythemia.

Symptoms

Symptoms of essential thrombocythemia can vary among individuals as it progresses gradually, leading to increased production of platelets in the bone marrow and elevated platelet levels. It is possible to have this condition without experiencing any symptoms. However, as platelet levels rise, you may start to exhibit symptoms associated with blood clotting. While blood clots can develop anywhere in the body, they tend to occur more frequently in the brain, hands, or feet in cases of essential thrombocythemia.

Essential thrombocythemia manifests through signs and symptoms that arise as a result of elevated platelet counts, leading to the formation of blood clots (thrombi). These symptoms may include:

• Pain, swelling, and redness in the arms or legs: This can occur due to deep vein thrombosis, which refers to a blood clot forming in a vein deep within the body.
• Shortness of breath, chest pain, and cough: These symptoms may be indicative of a pulmonary embolism, which occurs when a blood clot lodges in the lungs.
• Chest pain, shortness of breath, and nausea: These symptoms can signify a heart attack caused by a blood clot.

When a blood clot forms in the arteries that carry blood to the brain, it can lead to a temporary interruption of blood flow to a specific area of the brain. This interruption can result in a stroke or a transient ischemic attack (TIA), which are characterized by the following signs and symptoms:

• Headaches
• Dizziness
• Weakness or numbness on one side of the body
• Blurred or double vision
• Slurred speech

In some cases, individuals with essential thrombocythemia (ET) and an exceptionally elevated platelet count may experience bleeding as a result of the condition. The signs and symptoms associated with bleeding in such cases can include:

• Easy bruising
• Nosebleeds
• Gastrointestinal (GI) bleeding
• Presence of blood in stools
• Blood in the urine

In addition to the previously mentioned signs and symptoms, essential thrombocythemia (ET) may also present with the following manifestations:

• Persistent fatigue
• Unexplained weight loss
• Recurring low-grade fevers
• Night sweats
• Pain, redness, and swelling in the hands or feet which results from reduced blood flow.
• Enlargement of the spleen

Cause

Essential thrombocythemia is a genetic disorder that is acquired rather than being present at birth. It occurs when certain genes within cells undergo mutations or changes. Specifically, the mutations affect the genes JAK2, CALR, and MPL, which are responsible for regulating the production of blood cells in the bone marrow.

• JAK2 gene encodes the JAK2 protein, which plays a role in controlling how stem cells produce blood cells. When this gene mutates, it disrupts the normal regulation of stem cell production.
• CALR gene provides instructions for producing the calreticulin protein. Calreticulin is believed to influence gene activity, cell growth and division, and programmed cell death. Mutations in the CALR gene can impact these processes.
• MPL gene, which stands for myeloproliferative leukemia virus, is an oncogene. Oncogenes have the potential to cause cancer. When the MPL gene mutates, it triggers a cascade of events that leads to excessive production of platelets by the overactive stem cells.

In summary, the mutations in these genes lead to an abnormal increase in platelet production, exceeding the body’s needs, and resulting in essential thrombocythemia.

Risk factors

The following factors increase the risk in developing essential thrombocythemia.

• Age: Usually, this illness affects persons between the ages of 60 and 80. People under the age of 40 are involved in about 20% of all cases. Rarely does this problem affect children.
• Gender: People with this syndrome are twice more likely to affect female than male.
• Family history: The patient is more likely to develop the condition if someone in the family is diagnose with the condition.