When living with a myeloproliferative neoplasm (MPN), you will likely need to meet with your care team on a regular basis. Your doctor may want you to undergo testing every couple of months. Blood tests often include a complete blood count, which measures the levels of each type of blood cell in your blood, including your platelets. Monitoring your blood cell levels helps your doctor determine how your MPN is progressing and analyze whether treatments are working. Tests may also show whether you’re at risk for developing complications — health problems that develop following another health condition or treatment.

To learn more about platelet counts, myMPNteam spoke with Dr. Andrew Kuykendall, a physician specializing in hematology and oncology at Moffitt Cancer Center in Tampa, Florida. Dr. Kuykendall primarily focuses on treating people with MPNs.

What Are Platelets?

Platelets, also called thrombocytes, are very small blood cells. They are made by stem cells in the bone marrow (the spongy tissue found inside certain bones). Stem cells also make red blood cells and white blood cells.

Platelets are responsible for helping your blood form clots when there is an injury to a blood vessel. During the blood clotting process, platelets stick to each other and to the edges of the damaged blood vessel, eventually plugging up the hole and stopping the bleeding.

How MPNs Affect Platelet Counts

Doctors can measure your platelet count (how many platelets are in your blood) using a complete blood count test. Normally, people have between 150,000 and 450,000 platelets per microliter of blood.

In people with MPNs, stem cells make high levels of one or more types of blood cells, and platelet counts are often affected. There are three classic types of MPNs:

• Essential thrombocythemia, which leads to very high platelet levels
• Polycythemia vera, which leads to high red blood cell counts and often also causes platelet and white blood cell levels to rise
• Primary myelofibrosis, which causes abnormal blood cells and scar tissue to build up in the bone marrow and may lead to either high or low platelet counts

Abnormally high or low platelet counts are sometimes linked to complications for people with MPNs. Knowing your blood cell counts helps your doctor understand whether you’re at risk for developing health problems and determine which treatments may be the best fit.

Watch MPN expert Dr. Andrew Kuykendall discuss platelet counts in MPNs.

Low Platelet Counts While Living With an MPN

Thrombocytopenia (low platelet levels) is sometimes a problem for people with MPNs, although high platelet counts are more common. Low platelet levels can lead to bleeding problems, including:

• A cut that won’t stop bleeding
• Frequent bruises
• Nosebleeds
• Bleeding gums
• Heavy menstrual periods
• Blood in the urine or stool
• Petechiae (tiny red or purple spots under the skin)

Treatments for Low Platelet Counts

People with low platelet levels may need to limit alcohol and stop taking medications such as aspirin or anti-inflammatory drugs. These substances may make bleeding worse. People at risk of bleeding complications should also avoid activities that could lead to cuts and bruises.

If you have bleeding problems, or if you have fewer than 10,000 platelets per microliter of blood, you may need a platelet transfusion. In this case, you will receive platelets from a donor. Another possible treatment option for bleeding problems is an antifibrinolytic medication such as Trasylol (aprotinin) or Lysteda (tranexamic acid).

Doctors may recommend a stem cell transplant for certain people with MPNs. During this procedure, you undergo high-dose chemotherapy or radiation treatments and then receive new stem cells from a donor. Usually, this treatment is only given to people with higher-risk myelofibrosis. However, people with lower-risk myelofibrosis who have low platelet levels may also be able to undergo a stem cell transplant.

High Platelet Counts: Symptoms, Risks, and Treatments

MPNs often lead to thrombocytosis, or high platelet counts, which can cause health risks.

“One of the biggest complications of these diseases is thrombotic events,” said Dr. Kuykendall.

Thrombotic events are caused by abnormal blood clots, which occur when platelets form a clot within an artery or vein and block normal blood flow. A blood clot, also called thrombosis, can lead to more serious problems like a heart attack or stroke.

Blood clots may be a problem for some people with high platelet levels. However, high platelet counts may also lead to the same bleeding problems caused by low platelet levels.

Symptoms Related to High Platelet Counts

Too many platelets in the blood can cause some of the symptoms associated with MPNs. According to Dr. Kuykendall, MPNs sometimes cause unusual feelings called paresthesias.

“Paresthesias are numbness and tingling and sensations typically occurring in the fingers and the toes,” he said. “A lot of times this has to do with platelet and blood vessel interactions that occur with essential thrombocythemia.”

Platelets can also lead to other blood vessel problems. “I think with essential thrombocythemia what we see more commonly are headaches and some of these microvascular symptoms, to use a broad term. That would be like ringing in the ears, headaches, [and] fullness in the head.”

Do High Platelet Counts Put You at Risk for Complications?

High levels of red blood cells or white blood cells are more strongly linked to MPN complications than high levels of platelets. The risk of complications is much less clear when it comes to high platelet counts.

“This association between high platelets and thrombotic events has been looked at in a variety of fashions over the past 50 years now, and really nothing conclusive has come out of that,” reported Dr. Kuykendall. “In fact, large studies have shown really no correlation between higher platelet counts and an increased risk of thrombosis. If there’s anything that’s certain, it’s that if platelet counts get to maybe over a million or over 1.5 million, there’s an increased risk of bleeding that occurs.”

This means that, even if you have very high platelet levels, your doctor may not be too concerned about blood clots. You may have to take precautions or receive treatment to reduce your risk of bleeding problems, though.

Risk Factors for Blood Clots

Platelet counts may not increase your risk of blood clots — but other factors do. Dr. Kuykendall explained, “Across MPNs, we know that age, prior thrombotic events, and the type of driver mutation you have impacts your risk for thrombosis. Now, most people with MPNs have a JAK2 mutation, and that seems to be the most thrombogenic mutation: That’s the one that’s most associated with blood clots in the arteries and in the veins.”

If you are older, have had blood clots in the past, or have a JAK2 mutation, you may be more likely to experience blood clot complications while living with an MPN. Other gene changes found in MPN cells — CALR mutations or MPL mutations — are less likely to lead to blood clotting.

Treatments for High Platelet Levels

Doctors consider a person’s risk of complications when recommending MPN treatment plans. People who are at low risk may not need any treatments, while people with high-risk MPNs may need more aggressive treatment options. Risk levels are also used to estimate outlook and, if you have myelofibrosis, determine the chances that the myelofibrosis will transform (turn into acute leukemia).

Watch and Wait

Dr. Kuykendall noted that people with MPNs may come into their doctor’s office, see that they have high levels of certain blood cells, and expect to receive treatments that help decrease these numbers. However, treatment is not always called for — many people with MPNs continue to live normally with high platelet counts. Doctors are usually less concerned with high platelet numbers and more focused on what these numbers may mean in terms of symptoms or future complications.

“Just because we can normalize a number, that only matters if that actually makes the patient healthier,” he said.

For some people who have a low risk of complications and few symptoms, active surveillance or a “watch and wait” approach may be best. This approach involves regular doctor’s visits and tests to keep an eye on the disease and determine whether it is getting worse.

Dr. Kuykendall noted that some people may feel confused when their doctor recommends not using any treatments. However, medications may not have a large benefit, and they can lead to negative side effects.

“We’re focusing more on the symptoms of the disease, other than thrombosis,” he said. “So we’re focusing more on headaches and paraesthesias and quality of life and fatigue and trying to see what types of interventions could potentially help. Otherwise, if patients are feeling well and are at low risk for thrombosis, absolutely we’d love them to not have to be on any medications and be living a relatively normal life.”

Treatments for Preventing Blood Clots and Reducing Symptoms

When a person with an MPN experiences symptoms or is at risk for thrombotic events, treatment may be needed. Low-dose aspirin can lower a person’s chances of blood clots and help prevent cardiovascular problems such as strokes and heart attacks. This is because aspirin can make the blood less “sticky.”

Dr. Kuykendall noted that aspirin can also help relieve platelet-related symptoms. For people at low risk of blood clots, “we can typically monitor those folks either on just a baby aspirin or on no medications whatsoever and just keep an eye on their disease,” he said.

Some people, however, have a higher chance of developing complications. “The high-risk group is the one we think benefits the most from that extra layer of therapy — that cytoreductive therapy,” he said.

Cytoreductive treatments prevent the body from making new blood cells and help lower blood cell counts. These medications may include:

• Hydrea (hydroxyurea)
• Interferon drugs such as Intron A (interferon alfa-2b) or Pegasys (peginterferon alfa-2a)
• Agrylin (anagrelide)
• Jakafi (ruxolitinib)

Another possible treatment for high platelet levels is plateletpheresis. During this procedure, a machine removes some of your blood, takes out the platelets, and then returns the blood to your body. Medications and plateletpheresis can help bring platelet counts back into the normal range.

Talk With Others Who Understand

On myMPNteam, the social network for people living with myeloproliferative neoplasms and their loved ones, more than 1,800 members come together to ask questions, give advice, and share their stories with others who understand life with MPNs.

Are you living with an MPN? Do you have high or low platelet counts? Share your experience in the comments below, or start a conversation by posting on myMPNteam.