ADAM Health Encyclopedia

Thrombotic thrombocytopenic purpura

Definition

Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that causes blood clots to form in blood vessels around the body.

See also: Hemolytic-uremic syndrome

Alternative Names

Causes

In some cases, this disease is caused by the lack of an enzyme (a type of protein) that is involved in blood clotting. Not having enough of this enzyme causes clotting substances (platelets) in the blood to clump. As the platelets clump together, there are fewer platelets available in the bloodstream. This can lead to bleeding under the skin and purple-colored spots called purpura. It also can cause red blood cells to break apart and be destroyed prematurely.

TTP can lead to low platelets, low red blood cell count (caused by premature breakdown of red blood cells), abnormal kidney function, and problems with the nervous system.

Most cases of this disorder have no known cause, but some cases may be caused by a lack of the ADAMTS13 gene at birth. This gene gives the instructions for making the enzyme involved in blood clotting. The condition also may be related to cancer, chemotherapy, HIV infection, hormone replacement therapy and estrogens, and a number of commonly used medications (including ticlopidine, clopidogrel, and cyclosporine A).

Symptoms

• Fever
• Weakness
• Easy fatigue
• Pallor
• Shortness of breath on exertion
• Heart rate over 100 beats per minute
• Purplish spots in the skin produced by small bleeding vessels near the surface of the skin (purpura)
• Bleeding into the skin or mucus membranes
• Headache
• Confusion
• Speech changes
• Changes in consciousness
• Yellowish color to the skin (jaundice)

Exams and Tests

• Platelet count is low
• CBC shows anemia
• Bilirubin is high
• Blood smear shows broken red blood cells (schistocytes) and fragmented blood cells
• Urinalysis shows protein or very tiny blood particles
• Creatinine level is high
• Mucus membrane biopsy shows platelet clots in small blood vessels

Treatment

Plasma exchange (plasmapheresis) is used to remove unwanted substances from the blood and to replace the missing enzyme that normally breaks down proteins (protease).

First, you will have your blood drawn as if you were donating blood.The plasma portion of the blood will be passed through a cell separator. The remaining portion of the blood will be saved, plasma will be added to it, and the blood will be returned to you via a transfusion.

In people who have thrombotic thrombocytopenic purpura, this treatment is repeated daily until blood tests show improvement. People who do not respond to this treatment, or who have frequent recurrences, may need to have surgery to remove the spleen. Or, they may need to get drugs that suppress the immune system (such as corticosteroids).

Outlook (Prognosis)

Plasmapheresis has improved the outcome of this disease so that most patients now recover completely. However, some people can die from this disease. In people who don't recover, this condition can become long-term (chronic).

Possible Complications

• Kidney failure
• Severe bleeding (hemorrhage)
• Stroke

When to Contact a Medical Professional

Call your health care provider if you have any unexplained bleeding.

Prevention

Because the specific cause is unknown, there is no known way to prevent this condition.