Platelet Disorders Thrombotic Thrombocytopenic Purpura (TTP)
What is TTP?
TTP is a rare, life-threatening blood disorder. In TTP, blood clots form in small blood vessels throughout your body. The clots can limit or block the flow of blood to your organs, such as your brain, kidneys, and heart. This can prevent your organs from working properly and can damage your organs.
The increased clotting that occurs in TTP also uses up your platelets. Platelets are tiny blood cells that help form blood clots. These cell fragments stick together to seal small cuts and breaks in your blood vessels to stop bleeding. When your platelets are used up, you do not have enough platelets to form blood clots when necessary. This may cause bleeding and bruising.
- “Thrombotic” refers to the blood clots that form.
- “Thrombocytopenic” means the blood has a lower-than-normal platelet count.
- “Purpura” refers to purple bruises caused by bleeding under your skin.
TTP usually occurs suddenly and lasts for days or weeks, but it can continue for months. TTP can also cause red blood cells to break apart faster than your body can replace them. This leads to a rare form of anemia called hemolytic anemia.
TTP can be fatal. Without treatment, it can cause long-term problems, such as brain damage or a stroke.
What are the symptoms?
The symptoms of TTP may happen suddenly. Most people who have inherited TTP begin to have symptoms soon after birth. However, some do not have symptoms until they are adults.
The symptoms of TTP are caused by blood clots, a low platelet count, and damaged red blood cells. Your symptoms may include:
- Petechiae, which are small, flat red spots under the skin caused by blood leaking from blood vessels
- Purpura, which is bleeding in your skin that can cause red, purple, or brownish- yellow spots
- Paleness or jaundice (a yellowish color of the skin or whites of the eyes)
- Extreme tiredness
- A fever
- A fast heart rate or shortness of breath
- Headache, speech changes, confusion, coma, stroke, or seizure
- A low amount of urine, or protein or blood in your urin
- Feeling sick to your stomach (nausea), vomiting, and diarrhea
What causes TTP?
TTP occurs when you do not have the right amount of an enzyme (a type of protein in your blood) called ADAMTS13. This enzyme controls how your blood clots. If you do not have enough ADAMTS13, your body makes too many blood clots.
TTP can be inherited or acquired. “Inherited” means that your parents passed the gene for the disease on to you. In inherited TTP, the ADAMTS13 gene is faulty. Mutations, or changes, in the ADAMTS13 gene can cause your body to make an ADAMTS13 enzyme that does not work properly. If you inherit TTP, you are born with two copies of the faulty gene — one from each parent. Most often, the parents each have one copy of the faulty gene but have no signs or symptoms of TTP.
“Acquired” means that you were not born with the disease, but you developed it due to another disease or condition. In acquired TTP, the ADAMTS13 gene is not faulty. Instead, your body makes antibodies (proteins) that stop the ADAMTS13 enzyme from working properly.
The following factors can raise your risk of TTP.
- Age: Acquired TTP mostly occurs in adults, but it can affect children. Inherited TTP mainly affects newborns and children.
- Other medical conditions: Cancer, HIV, lupus, and infections can cause TTP. Obesity and pregnancy also can raise your risk.
- Race and ethnicity: Acquired TTP occurs more often in African Americans than in other racial groups.
- Sex: Acquired TTP occurs more often in women than in men.
- Some medical procedures: Surgery and blood and marrow stem cell transplant can raise your risk of TTP.
- Some medicines: Chemotherapy, ticlopidine, clopidogrel, cyclosporine A, and therapy can cause TTP. Quinine, which is a substance often found in tonic water and nutritional health products, can also raise your risk.
How is it diagnosed?
To diagnose TTP, your provider will ask about your medical and family history. They will ask about your symptoms and do a physical exam to look for signs of TTP.
Your provider may order one or more of the blood tests listed below.
- ADAMTS13 assay: A lack of activity in the ADAMTS13 enzyme causes TTP. For this test, a sample of blood is drawn from a vein, usually in your arm. The blood is sent to a special lab to test for the enzyme’s activity.
- Bilirubin test: When red blood cells die, they release a protein called into your bloodstream. The body breaks down hemoglobin into a compound called bilirubin. If you have TTP, your bilirubin level may be high because your body is breaking down red blood cells faster than normal.
- Blood smear: For this test, some of your blood is put on a slide. A microscope is used to look at your blood cells. If you have TTP, your red blood cells will look torn and broken.
- Bone marrow tests: These tests check whether your bone marrow is healthy.
- Complete blood count (CBC): This test measures the levels of red blood cells, white blood cells, and platelets in your blood.
- Coombs test: This blood test is used to find out whether TTP is causing hemolytic anemia. In TTP, hemolytic anemia develops because red blood cells are broken into pieces as they try to squeeze around blood clots. When TTP is the cause of hemolytic anemia, the Coombs test is negative. The test is positive if antibodies (proteins) are destroying your red blood cells.
- Kidney function tests and urine tests: These tests show whether your kidneys are working well. If you have TTP, you may have blood or protein in your urine. Also, your blood creatinine level may be high. Creatinine is a blood product that is normally removed by the kidneys.
- Lactate dehydrogenase (LDH) test: This blood test measures a protein called LDH. Hemolytic anemia causes red blood cells to break down and release LDH into the blood. LDH is also released from tissues that are injured by blood clots because of TTP.
How is TTP treated?
TTP can cause life-threatening complications if it is not treated right away. Plasma treatments and medicines are the most common ways to treat TTP. If these treatments do not work, you may need surgery. Treatments are done in a hospital.
- Therapeutic plasma exchange (plasmapheresis) is used to treat acquired TTP. In this procedure, the liquid part of your blood (plasma) is replaced with donor plasma, using a machine that collects the cells in the blood. It removes antibodies (proteins) in your blood that damage your ADAMTS13 enzyme. Plasma exchange also replaces the ADAMTS13 enzyme. You will get this treatment daily until any organ problems have gone away, your platelet count is stable, and damage to your red blood cells has stopped.
- Plasma infusion is used to treat inherited TTP. For this treatment, donor plasma is given through an intravenous (IV) line inserted into a vein. This is done to replace the missing or faulty ADAMTS13 enzyme.
Plasma treatments usually continue until your blood tests results and symptoms improve. This can take days or weeks, depending on your condition. You will stay in the hospital while you recover.
Corticosteroids, such as prednisone, are commonly used together with plasma treatments. These medicines, called steroids for short, can slow or stop your body from forming antibodies against the ADAMTS13 enzyme. The steroids used to treat TTP are different from the illegal steroids that some athletes take to enhance performance. Corticosteroids are not habit-forming, even if you take them for many years.
Other medicines used to treat TTP include rituximab, vincristine, cyclophosphamide, and cyclosporine A.
Surgery to remove your spleen
The spleen is an organ in your upper left abdomen. Your spleen makes the antibodies that block ADAMTS13 enzyme activity. Removing your spleen stops your body from making these antibodies. This surgery is used to treat TTP if other treatments do not work for you.
What health problems can TTP cause?
Some people fully recover from TTP. However, relapses (flare-ups) are common. They can happen in people who have acquired and inherited TTP. If you have frequent relapses, you may need ongoing treatment.
Without treatment, TTP can cause frequent blood clots. These blood clots can block blood flow to your organs and cause complications including:
- A stroke
- Brain damage
- Problems with your kidneys
- Reduced blood flow to your digestive system, which may cause diarrhea, pain in your abdomen, and other digestive problems
- Reduced blood flow to your heart, which may cause a heart attack
Learn how you can manage TTP to avoid serious complications.