MedlinePlus Medical Encyclopedia: Thrombotic thrombocytopenic purpura

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Thrombotic thrombocytopenic purpura

Contents of this page:
Illustrations Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests	Treatment Expectations (prognosis) Complications Calling your health care provider Prevention

Illustrations

Blood cells

Alternative names Return to top

TTP

Definition Return to top

TTP is a blood disorder characterized by low platelets, low red blood cell count (caused by premature breakdown of the cells), abnormalities in kidney function, and neurological abnormalities. A similar clinical condition with overlapping features is hemolytic-uremic syndrome.

Causes, incidence, and risk factors Return to top

This disease is caused by a deficiency in the von Willebrand Factor cleaving protease, known as ADAMTS13. The loss of this enzyme results in large complexes of von Willbrand factor circulating in the blood, which in turn causes platelet clumping and red blood cell destruction.

Although most cases have no known cause, some cases may be related to a deficiency of ADAMTS13 at birth, cancer, chemotherapy, HIV infection, hormone replacement therapy and estrogens, and a number of medications in common use (including ticlopidine, clopidogrel, and cyclosporine A).

Symptoms Return to top

Fever
Weakness
Easy fatigue
Pallor
Shortness of breath on exertion
Heart rate over 100 per minute
Purpura -- purplish discolorations in the skin produced by small bleeding vessels near the surface of the skin
Bleeding into the skin or mucus membranes
Headache
Confusion
Speech changes
Alterations in consciousness
Yellowish color to the skin (jaundice)

Signs and tests Return to top

Platelet count is low
CBC shows anemia
Bilirubin is high
Blood smear shows schistocytes and fragmented blood cells
Urinalysis shows protein or microscopic blood particles
Creatinine level is high
Mucus membrane biopsy reveals platelet clots in small blood vessels

Treatment Return to top

Plasmapheresis, or plasma exchange, is used to remove unwanted substances from the blood (large von Willebran protein complexes), and to replace the missing protease. Blood is withdrawn from the patient as for a blood donation.

Then the plasma portion of the blood is passed through a cell separator. The remaining portion of the blood is saved, reconstituted with fresh plasma, and returned to the patient as a blood transfusion.

In thrombotic thrombocytopenic purpura, this treatment is repeated daily until blood tests show improvement. People who do not respond to this treatment, or have frequent recurrences, may require the removal of the spleen, corticosteroids, or other immune suppression.

Expectations (prognosis) Return to top

Plasmapheresis has improved the outcome of this disease so that 80 to 90% of patients now recover completely. However, fatalities still occur. With relapses, the remaining cases become chronic (long-term).

Complications Return to top

Kidney failure
Hemorrhage
Stroke

Calling your health care provider Return to top

Call your health care provider if unusual or unexplained bleeding occurs.

Prevention Return to top

Because the specific cause is unknown, specific prevention is also unknown.

Update Date: 10/13/2003

Updated by: Corey Cutler, M.D., M.P.H., F.R.C.P.C, Department of Medical Oncology, Dana-Farber Cancer Institute; Instructor in Medicine, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.

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