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Thrombotic Thrombocytopenic Purpura (TTP)

What is TTP?

Thrombotic thrombocytopenic purpura (TTP) is a rare and serious blood disorder. It causes blood clots to form in small blood vessels throughout the body. TTP also reduces the number of platelets in the blood and can cause red blood cells to break down.

Blood clots can block blood flow and decrease the amount of oxygen that can get to organs. This can cause serious medical issues.

TTP can develop suddenly, and recovery can take several weeks or months. It is important to get treatment for TTP right away. TTP flare ups or relapse can happen, and ongoing medical care is important.

Components of Blood

Blood has 4 main parts:

  • Red blood cells carry oxygen through the body.
  • White blood cells fight infection.
  • Platelets help stop bleeding after a cut or bruise.
  • Plasma is the liquid part of blood.

Causes of TTP

TTP develops when there is a problem with an enzyme called ADAMTS13. This enzyme helps control how platelets work to stop bleeding.

When ADAMTS13 does not work normally, the platelets clump together too often and form blood clots. The clots can stop blood flow to important organs such as the brain and kidneys.

When extra clots form, the blood also uses up platelets. This lowers the number of platelets available to stop bleeding when needed. Having fewer platelets means bleeding problems or bruising happens more easily.

The extra clots also float in the blood and damage red blood cells. Having too few healthy red blood cells causes anemia. This condition causes someone to feel tired and weak.

Acquired TTP

The most common way TTP occurs is called acquired TTP. This happens when the body’s immune system makes antibodies that block an enzyme called ADAMTS13. Antibodies help fight infection. The antibodies attack the ADAMTS13 enzyme by mistake. When this happens, ADAMTS13 no longer works the way it should.

Acquired TTP develops without a clear cause. There is no way to prevent it. Parents cannot pass acquired TTP to their children.

Inherited TTP

Inherited TTP occurs when there is a problem with the gene that controls ADAMTS13. This is a rare cause of TTP. Parents can pass the gene for inherited TTP on to their children.

Symptoms of TTP

Symptoms of TTP can be caused by blood clots, low platelet counts, or damage to red blood cells. Signs and symptoms of TTP include:

  • Flu-like symptoms, such as fever, headache, nausea, and vomiting
  • Feeling tired or weak
  • Confusion, changes in speech, or blurry vision
  • Chest pain, shortness of breath, or trouble catching their breath
  • Unexplained bleeding or bruises
  • Petechiae - small, red or purple “pinpoint” dots on the skin that may look like a rash
  • Pale skin
  • Jaundice - a yellowish color of the skin, palms of the hands, or the whites of the eyes

If your child has any of these symptoms, contact your care team right away.

Petechiae illustration

Petechiae are flat, rash-like dots on the skin due to bleeding.

Diagnosis of TTP

Your health care team may refer your child to a hematologist. This doctor specializes in blood disorders. They do a physical exam and ask about your child’s symptoms. If they suspect TTP, the doctor may order the following tests:

  • ADAMTS13 test. This measures how active the ADAMTS13 enzyme is. If the activity is low, your child may have TTP.
  • Blood smear test. Doctors place a small amount of your child’s blood on a slide. They look at the blood under a microscope. If your child has TTP, the red blood cells appear broken or torn.
  • Bilirubin test. When red blood cells are damaged, they release the protein hemoglobin into your blood. Hemoglobin breaks down into bilirubin. If your child’s blood has high levels of bilirubin, they could have TTP.
  • Complete blood count (CBC). This test measures the number of red blood cells, white blood cells, and platelets in your child’s blood. People with TTP have low numbers of red blood cells and platelets in their blood.
  • Creatinine test. Creatinine is a blood waste product that is usually removed by the kidneys. Those with TTP may have high levels of creatinine in the blood.
  • Lactate dehydrogenase (LDH) test. This is an enzyme found in most cells. When cells break, the enzyme releases into the blood. If your child has TTP, their LDH levels will be higher than normal.
  • Urine and kidney function tests. These tests can tell if your child’s kidneys work as they should. If your child has TTP, they may have protein or blood cells in their urine.

Treatment of TTP

Your child needs treatment to prevent a stroke, seizure, bleeding, or further damage to their organs. Most children do well when TTP treatment begins soon after diagnosis.

TTP is often treated with plasma therapy. It can also be treated using medication or surgery.

Plasma therapy

There are two kinds of plasma therapy. One is plasma exchange. The other is fresh frozen plasma infusion.

Plasma exchange
removes unhealthy plasma and exchanges it with healthy plasma.

  • Your child’s health care team places an IV in your child’s vein.
  • The IV draws blood from the body.
  • Staff remove the plasma from this blood.
  • They mix the blood with healthy plasma.
  • They put the blood with new plasma back into your child’s body.

Plasma therapy is usually used to treat acquired TTP.

Fresh frozen plasma
is usually used to treat inherited TTP.

  • Staff give plasma to your child through an IV.
  • This plasma is added to your child’s blood.
  • The plasma contains the ADAMTS13 enzyme and can replace the abnormal or missing enzyme in your child’s blood.

Your child repeats plasma therapy treatments until symptoms get better. This can take some time. Talk to your health care team about how long it may take for your child.


Your child’s doctor may prescribe medicines to help the immune system stop attacking ADAMTS13. These medicines include steroids and rituximab.

Your child may also get a medicine that balances von Willebrand factor, a protein that helps platelets stick together to stop bleeding. The doctor might prescribe this along with other medicines for TTP.


Rarely, surgeons must remove a child’s spleen (splenectomy) if other treatments do not work. Antibodies that attack the ADAMTS13 enzyme are created in the spleen. Removing the spleen prevents the body from creating these antibodies.

Living with TTP

With proper care, your child can live without symptoms. TTP flare ups or relapse can occur, and ongoing medical care is important. If symptoms return, contact your hematology care team as soon as possible to restart treatment.

To help keep your child safe, talk to your child’s health care team before:

  • Starting or taking any new medicines that could thin the blood
  • Doing intense physical activity or activities that could put someone at risk for falls or injury

TTP is a serious condition. If symptoms appear, they must be treated right away. Go to every scheduled appointment and follow the instructions of your health care team.

Key Points

  • Thrombotic thrombocytopenic purpura (TTP) is a disease that causes platelets to clump together and form blood clots.
  • Most of the time TTP is caused by antibodies that attack an enzyme in the body. TTP can also be passed down through families.
  • Symptoms are treated through medicines and plasma exchange.
  • After treatment, continue to watch for symptoms and seek medical care right away if symptoms develop.

Reviewed: September 2022