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TTP is a rare but serious blood disorder. It can cause blood clots and not enough of a type of blood cell called platelets. It can also cause red blood cells to break down.

TTP stands for thrombotic thrombocytopenic purpura (throm-BAH-tick THROM-bow-sigh-toe-PEE-nick PURR-pur-uh).

About your blood

Knowing about your blood can help you understand TTP. The 4 main parts of your blood are:

  • Red blood cells that carry oxygen through the body,
  • White blood cells that fight infection,
  • Platelets that clump, or clot, to stop the bleeding when you are hurt, and
  • Plasma, the liquid part of blood that carries nutrition, proteins, and enzymes through the body. Enzymes are chemicals that help your body work.

What is ADAMTS13?

The liquid part of your blood, called plasma, includes 2 important substances. One is a protein called von Willebrand factor. The other is an enzyme called ADAMTS13. They work with your platelets, the blood cells that help form clots, when you have a cut or injury.

Von Willebrand factor is a sticky substance. It helps platelets clump together if there is bleeding. ADAMTS13 breaks the long strands of von Willebrand factor into small pieces. If it does not, the long strands cause problems. They attract platelets, and blood clots form when they are not needed.

What causes TTP?

Most often, TTP happens when the body’s immune system starts making substances that block ADAMTS13 activity. These substances are called antibodies. They attack the ADAMTS13 enzyme by mistake. TTP that happens this way is called “acquired TTP.” Parents cannot pass it to their children.

TTP can also happen when there is a problem with the gene that controls the ADAMTS13 enzyme. However, this is rare. This form of TTP is called “inherited TTP.” Parents can pass this form of TTP to their children.

Healthy blood

What does TTP do to your blood?

Platelets clump together to form clots when there is bleeding or an injury. ADAMTS13 keeps them from clumping unless needed. The picture above shows how this works.


When ADAMTS13 is not working normally, the platelets clump together too often. They form small clots all through the body. These clots can stop blood flow to important organs such as the brain and kidneys. The picture above shows what happens.

Forming the extra clots uses up platelets. This lowers the number of platelets you have available to stop bleeding when needed. Having fewer platelets than normal means you can develop bleeding problems or bruise more easily.

The extra clots also float in the blood and damage red blood cells. Red blood cells carry oxygen through your body. Having too few healthy red blood cells causes anemia (uh-NEE-mee-uh). This condition makes your child feel tired and weak.

What are the symptoms of TTP?

You might notice some or all of these symptoms if your child has TTP:

  • Symptoms like the flu, with fever, headache, nausea, and vomiting
  • Feeling tired or weak
  • Confusion, changes in speech, or blurry vision
  • Chest pain or shortness of breath (trouble catching their breath)
  • Unexplained bleeding, bruises, or small red dots on the skin or inside the mouth
  • Pale skin or jaundice (a yellowish color to the skin or eyes)

How is TTP treated?

Your child needs treatment to prevent a stroke, seizure, bleeding, or further damage to their organs. Most children do well when TTP is treated quickly.

Plasma exchange

Plasma exchange uses a machine to take the liquid called plasma out of your child’s blood and replace it with new plasma. The goal is to remove the antibodies fighting the ADAMTS13 enzyme and to replace the ADAMTS13 enzyme with enzyme that is working correctly.

Medicines for TTP

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

Your child might also get a medicine that works against von Willebrand factor. It keeps extra clots from forming. The doctor might prescribe this along with other medicines for TTP.

After TTP treatment

Your child will continue seeing a hematologist (a doctor who treats blood disorders). They will keep taking medicine until their ADAMTS13 activity level is normal.

Having TTP one (1) time raises your child’s risk of getting it again. If you notice any of the TTP symptoms listed above, please call Hematology at 901-595-5041. Ask for a member of the General Hematology team.


If you have questions about TTP or what to look for, talk to your child’s doctor or nurse. You may also talk to the Hematology nurse case manager.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

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