Thrombotic thrombocytopenic purpura (TTP) is a rare, severe blood disorder that causes blood clots to form in small blood vessels.

TTP can affect children and adults. People may inherit the condition or develop it through certain health conditions or medical treatments.

The blood clots that form with TTP can restrict blood flow to the organs, leading to various health problems. Without prompt treatment, TTP can be life threatening.

This article looks at TTP symptoms, causes, diagnosis, treatment, and outlook.

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TTP is a rare blood disorder that causes blood clots to form in the body’s small blood vessels. These blood clots can restrict or block blood flow to the organs, causing damage and affecting organ function.

Platelets are blood cells that help the blood clot to prevent bleeding. The formation of blood clots with TTP uses up platelets, which means the blood does not have enough platelets to form the necessary clots. This can lead to bruising and bleeding under the skin.

Thrombotic refers to the formation of a blood clot in a blood vessel, and thrombocytopenic means a reduced platelet count. Purpura is the term for the bruises that occur due to bleeding under the skin.

TTP also destroys red blood cells faster than the body can produce them, causing hemolytic anemia.

TTP can be life threatening, and without treatment, it may lead to serious complications, including stroke or brain damage.

Symptoms of TTP include:

Symptoms of TTP can develop suddenly. Some people may have symptoms of inherited TTP shortly after birth, but others may not develop symptoms until they are adults.

TTP occurs when people have a severe deficiency of the ADAMTS13 enzyme, a protein in the blood that controls blood clotting. Without enough ADAMTS13, excess blood clots form.

People may inherit TTP or acquire it during their lifetime. They can also inherit a faulty ADAMTS13 gene, which means the gene produces an ADAMTS13 enzyme that does not function properly.

In most diagnoses of inherited TTP, each parent has one copy of the faulty ADAMTS13 gene, but they do not have any TTP signs or symptoms. People with inherited TTP have two copies of the ADAMTS13 mutation, as they receive one copy of the genetic mutation from each parent.

People with acquired TTP have a normal ADAMTS13 gene, but the body creates antibodies that prevent the ADAMTS13 enzyme from working correctly. This may happen due to certain health conditions or medical treatments.

Inherited TTP usually occurs in infants and children. Acquired TTP usually develops in adulthood but can also occur in children.

Risk factors for developing TTP include:

  • having certain medical conditions, including HIV and lupus
  • having obesity
  • being pregnant
  • being female, as acquired TTP is more common in females than males
  • receiving surgery and stem cell transplant of blood and marrow, which can increase the risk of TTP
  • taking or ingesting quinine, an antimalarial drug and substance in tonic water that may increase the risk of TTP

A 2016 study notes that Black people are at an increased risk of developing TTP and suggests that genetic factors may be contributors to their increased risk.

Certain medications and substances may cause TTP, including:

A doctor will assess any symptoms of TTP involves a doctor performing a physical examination, as well as requesting and evaluating personal and family histories.

Signs of TTP may appear differently in each person and can be similar to those in other conditions. If a doctor suspects TTP, they will typically order a range of tests, such as:

  • ADAMTS13 assay: A healthcare professional takes a blood sample for laboratory testing to check the activity of the ADAMTS13 enzyme.
  • Complete blood count (CBC): This blood test can show levels of red blood cells, white blood cells, and platelets in the blood.
  • Blood smear: A blood smear examines a blood sample under a microscope to check for damage to red blood cells.
  • Bilirubin test: TTP increases the destruction of red blood cells, which in turn increases a substance called bilirubin.
  • Coombs test: This test checks a blood sample for antibodies that destroy red blood cells. As TTP is the cause for red blood cell damage, this test is usually negative.
  • Lactate dehydrogenase (LDH) test: The breakdown of red blood cells, and tissue injury due to TTP blood clots, can release a protein called LDH. This test measures levels of LDH in the blood.
  • Electrocardiogram (ECG): People with TTP may have symptoms affecting the heart, so doctors may use an ECG to check the heart’s electrical activity.
  • Kidney function tests: People with TTP may have kidney problems, so doctors check how well the kidneys are working.
  • Enzyme-linked immunosorbent assay (ELISA): A test which checks for antibodies in the blood, to identify if TTP is inherited or acquired.

People with TTP need immediate treatment, as delayed treatment may increase the risk of life threatening complications. Doctors may begin treatment before the results of ADAMTS13 testing can confirm a diagnosis.

Therapeutic plasma exchange (TPE) is the first-line treatment for acquired TTP. TPE replaces plasma, the liquid component of blood, with healthy donor plasma.

The new plasma supplies the right amount of ADAMTS13 enzyme and removes antibodies that damage the enzyme. People will have TPE daily until it resolves the issues from TTP.

Alongside TPE, people will also typically receive immunosuppressive drugs, such as glucocorticoids or rituximab, to target the antibodies that attack the ADAMTS13 enzyme.

Doctors use plasma infusion to treat inherited TTP. This delivers donor plasma intravenously to replace the ADAMTS13 enzyme deficiency.

In 2023, the Food and Drug Administration (FDA) approved the drug Adzynma for adults and children with inherited TTP.

Adzynma is a genetically engineered version of the ADAMTS13 enzyme. It works to replace the enzyme or reduce the risk of TTP symptoms, and may be a safe and effective TTP treatment.

If standard TTP treatments are not effective, healthcare professionals may prescribe surgery to remove the spleen. The spleen is an abdominal organ that produces antibodies that block the effects of the ADAMTS13 enzyme.

Without prompt treatment, TTP can cause life threatening complications and can be fatal. Prompt treatment with plasma treatments may help prevent this.

It is possible to fully recover from TTP. Relapses can occur, though, so people may need ongoing treatment to manage the condition.

TTP is a rare blood disorder that causes blood clots to develop in small blood vessels. It can damage organs and lead to them not working properly.

It is important that people contact a doctor immediately if they have any symptoms of TTP. The condition can be life threatening, but prompt treatment can help prevent severe or fatal complications.

Treatment may include plasma replacement therapies, medications, and in some cases, surgery to remove the spleen.