What causes platelets to rise quickly?

Featured Expert:

• Marlene Stephanie Williams, M.D.

“Platelets are the cells that circulate within our blood and bind together when they recognize damaged blood vessels,” says Marlene Williams, M.D., director of the Coronary Care Unit at Johns Hopkins Bayview Medical Center. “When you get a cut, for example, the platelets bind to the site of the damaged vessel, thereby causing a blood clot. There’s an evolutionary reason why they’re there. It’s to stop us from bleeding.”

What makes platelets change their shape?

Platelets, the smallest of our blood cells, can only be seen under a microscope. They’re literally shaped like small plates in their non-active form. A blood vessel will send out a signal when it becomes damaged. When platelets receive that signal, they’ll respond by traveling to the area and transforming into their “active” formation. To make contact with the broken blood vessel, platelets grow long tentacles and then resemble a spider or an octopus.

What is a healthy platelet count?

A normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. Having more than 450,000 platelets is a condition called thrombocytosis; having less than 150,000 is known as thrombocytopenia. You get your platelet number from a routine blood test called a complete blood count (CBC).

What it means to have too many platelets

The medical term for having too many platelets is thrombocytosis, and there are two types:

• Primary or essential thrombocytosis – Abnormal cells in the bone marrow cause an increase in platelets, but the reason is unknown.
• Secondary thrombocytosis – The same condition as primary thrombocytosis, but may be caused by an ongoing condition or disease such as anemia, cancer, inflammation, or infection.

When there are symptoms, they include spontaneous blood clots in the arms and legs, which if untreated can lead to heart attack and stroke. In severe cases, the patient might have to undergo a procedure called a platelet pheresis. This lowers the platelet count by removing the blood, separating out the platelets, and returning the red blood cells back to the body.

With secondary thrombocytosis, the symptoms are usually related to the associated condition. For example, if you have an infection or anemia, you treat those conditions and the platelet count comes down.

What it means to have too few platelets

When you don’t have enough platelets, it’s called thrombocytopenia. Symptoms include easy bruising, and frequent bleeding from the gums, nose, or GI tract. Your platelet count drops when something is preventing your body from producing platelets. There are a wide range of causes, including:

• Medications
• An inherited condition
• Certain types of cancer, such as leukemia or lymphoma
• Chemotherapy treatment for cancer
• Kidney infection or dysfunction
• Too much alcohol

How platelets relate to cardiovascular disease

If you have too many platelets, it can increase your risk for clotting. But often your cardiovascular risk has more to do with platelet function than platelet number. For example, you could have a healthy number of platelets, but if they’re sticking together too much it can increase your chance of having a heart attack or stroke.

Keeping track of your platelets

Too many platelets, too few platelets, abnormally functioning platelets, and related conditions such as blood clots, strokes, and heart attacks can be inherited. So it’s a good idea to alert your doctor when there’s a family connection.

“Although you may feel fine, your physician might want to keep a close eye on you and investigate whether or not you need medications to reduce the functioning of your platelets,” says Williams. “The most common blood-thinning medication is aspirin, although recent studies have shown that women under 65 who are otherwise healthy do not receive the same benefit from aspirin as men do. There is no concrete answer to that yet.”

If you have a new or existing heart problem, it's vital to see a doctor. Our heart health checklist can help you determine when to seek care.

Thrombocythemia is a disease in which your bone marrow makes too many platelets. Platelets are blood cell fragments that help with blood clotting. Having too many platelets makes it hard for your blood to clot normally. This can cause too much clotting, or not enough clotting.

What causes thrombocythemia?

There may be no single cause for thrombocythemia. It is believed to be caused by defects in the bone marrow’s platelet-making cells.

What are the symptoms of thrombocythemia?

Symptoms of thrombocythemia include:

• Blood clots in arteries and veins, most often in the hands, feet, and brain 

• Bruising easily

• Bleeding from the nose, gums, and GI (gastrointestinal) tract

• Bloody stools

• Bleeding after injury or surgery

• Weakness

• Headache and dizziness 

• Swollen lymph nodes

The symptoms of thrombocythemia may look like other blood disorders or health problems. Always see your healthcare provider for a diagnosis.

Dr. Kelly Metcalf Pate studies how platelets in the blood team together to stop bleeding and fight infection. Her team is studying whether a low platelet number impairs the body’s ability to defend itself from HIV.

Your healthcare provider will take your medical history and give you a physical exam. You may also have tests such as:

• CBC (complete blood count). This test measures the amount of red blood cells, white blood cells, and platelets in your blood.

• Blood smear. This test checks your platelets.

• Bone marrow aspiration or biopsy. This may be done to see if your bone marrow is healthy. It involves taking a small sample of bone marrow fluid (aspiration) or solid bone marrow tissue (called a core biopsy). The sample is checked under a microscope.

How is thrombocythemia treated?

Your healthcare provider will figure out the best treatment based on:

• Your age, overall health, and medical history

• How sick you are

• How well you can handle certain medicines, treatments, or therapies

• How long the condition is expected to last

• Your opinion or preference

Treatment may include:

• Chemotherapy. This is most often given with an oral chemotherapy medicine (hydroxyurea), or with interferon alpha. 

• Plateletpheresis. This is a procedure to remove extra platelets from your blood.

Living with thrombocythemia

Work with your healthcare provider to develop a treatment plan that meets your needs.

 It’s also important to:

• Avoid smoking, which may increase blood clots

• Control other health conditions such as high cholesterol, high blood pressure, and diabetes

• Avoid things that may increase bleeding, including medicines such as aspirin.

• Tell your healthcare provider if you notice bruising or other signs of bleeding.

Key points

• Thrombocythemia causes your body to make too many platelets in the bone marrow.

• Too many platelets can cause blood clots or bleeding.

• Symptoms include blood clots and signs of bleeding, such as bruises, bloody stools, and weakness.

• There may be no single cause for the disease. It is believed to be caused by defects in the bone marrow’s platelet-making cells.

• Treatment includes medicines and removing extra platelets from your blood.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.