Primary thrombocythemia is a rare blood clotting disorder that causes bone marrow to produce too many platelets. It’s also known as essential thrombocythemia.
Bone marrow is the spongelike tissue inside your bones. It contains cells that produce:
- red blood cells (RBCs), which carry oxygen and nutrients
- white blood cells (WBCs), which help fight infections
- platelets, which enable blood clotting
A high platelet count can cause blood clots to develop spontaneously. Normally, your blood begins to clot to prevent a massive loss of blood after an injury. In people with primary thrombocythemia, however, blood clots can form suddenly and for no apparent reason.
Abnormal blood clotting can be dangerous. Blood clots may block the flow of blood to the brain, liver, heart, and other vital organs.
This condition occurs when your body produces too many platelets, which can lead to abnormal clotting. However, the exact cause for this is unknown. According to the MPN Research Foundation, approximately half of people with primary thrombocythemia have a gene mutation in the Janus kinase 2 (JAK2) gene. This gene is responsible for making a protein that promotes the growth and division of cells.
When your platelet count is too high due to a specific disease or condition, it’s called secondary or reactive thrombocytosis. Primary thrombocythemia is less common than secondary thrombocytosis. Another form of thrombocythemia, inherited thrombocythemia, is very rare.
Primary thrombocythemia is most common among women and people over age 50. However, the condition can also affect younger people.
Primary thrombocythemia usually doesn’t cause symptoms. A blood clot may be the first sign that something is wrong. Blood clots can develop anywhere in your body, but they’re more likely to form in your feet, hands, or brain. The symptoms of a blood clot can vary depending on where the clot is located. Symptoms generally include:
- lightheadedness or dizziness
- numbness or tingling in your feet or hands
- redness, throbbing, and burning pain in your feet or hands
- changes in vision
- chest pain
- a slightly enlarged spleen
In rare cases, the condition can cause bleeding. This may occur in the form of:
Women who have primary thrombocythemia and also take birth control pills have a higher risk of blood clots. The condition is also particularly dangerous for women who are pregnant. A blood clot located in the placenta can lead to problems with fetal development or miscarriage.
- blurred vision
- weakness or numbness in the limbs or face
- shortness of breath
- difficulty speaking
- clammy skin
- squeezing pain in the chest that lasts for more than a few minutes
- shortness of breath
- pain that extends to your shoulder, arm, back, or jaw
Although less common, an extremely high platelet count may result in:
- bleeding from the gums
- blood in the stool
Call your doctor or go to the hospital immediately if you have symptoms of:
- a blood clot
- heart attack
- heavy bleeding
These conditions are considered medical emergencies and require immediate treatment.
Your doctor will first perform a physical examination and ask you about your medical history. Make sure to mention any blood transfusions, infections, and medical procedures you’ve had in the past. Also tell your doctor about any prescription and over-the-counter (OTC) medications and supplements you’re taking.
If primary thrombocythemia is suspected, your doctor will run certain blood tests to confirm the diagnosis. Blood tests may include:
- Complete blood count (CBC). A CBC measures the number of platelets in your blood.
- Blood smear. A blood smear examines the condition of your platelets.
- Genetic testing. This test will help determine whether you have an inherited condition that causes a high platelet count.
Other diagnostic testing may include bone marrow aspiration to examine your platelets under a microscope. This procedure involves taking a sample of bone marrow tissue in liquid form. It’s typically extracted from the breastbone or pelvis.
You’ll most likely receive a diagnosis of primary thrombocythemia if your doctor can’t find a cause for your high platelet count.
Your treatment plan will depend on a number of factors, including your risk of developing blood clots.
You may not need treatment if you don’t have any symptoms or additional risk factors. Instead, your doctor may choose to carefully monitor your condition. Treatment may be recommended if you:
- are over age 60
- are a smoker
- have other medical conditions, such as diabetes or cardiovascular disease
- have a history of bleeding or blood clots
Treatment may include the following:
- OTC low-dose aspirin (Bayer) may reduce blood clotting.
- Prescription medications can lower the risk of clotting or reduce platelet production in the bone marrow.
- Platelet pheresis. This procedure removes platelets directly from the blood.
Your outlook depends on a variety of factors. Most people don’t experience any complications for a long time. However, serious complications can occur. They can include:
- heavy bleeding
- heart attack
- pregnancy complications, such as preeclampsia, premature delivery, and miscarriage
Bleeding issues are rare, but may lead to complications such as:
There’s no known way to prevent primary thrombocythemia. However, if you’ve recently received a diagnosis of primary thrombocythemia, there are some things you can do to lower your risk of serious complications.
The first step is managing any risk factors for blood clots. Controlling your blood pressure, cholesterol, and conditions such as diabetes can help reduce the risk of blood clots. You can do this by exercising regularly and eating a diet that largely consists of fruits, vegetables, whole grains, and lean protein.
It’s also important to quit smoking. Smoking increases your risk of blood clots.
To further reduce your risk of serious complications, you should also:
- Take all medications as prescribed.
- Avoid OTC or cold medications that increase the risk of bleeding.
- Avoid contact sports or activities that increase the risk of bleeding.
- Promptly report abnormal bleeding or symptoms of blood clots to your doctor.
Before any dental or surgical procedures, make sure to tell your dentist or doctor about any medications you may be taking to lower your platelet count.
Smokers and people with a history of blood clots may need medications to reduce their platelet count. Others may not need any treatment.