Thrombotic thrombocytopenic purpura, acquired

The signs and symptoms of thrombotic thrombocytopenic purpura, acquired (acquired TTP) may include:^[1][2]

• Purplish bruises on the skin or mucous membranes (such as in the mouth). These bruises, called purpura, are caused by bleeding under the skin
• Pinpoint-sized red or purple dots on the skin. These dots, called petechiae, often are found in groups and may look like a rash.Bleeding under the skin causes petechiae.
• Paleness or jaundice (a yellowish color of the skin or whites of the eyes)
• Fatigue (feeling very tired and weak)
• Fever
• A fast heart rate or shortness of breath.
• Nausea or vomiting
• Headache, speech changes, confusion, coma, stroke, or seizure
• A low amount of urine, or protein or blood in the urine

Acquired TTP usually presents as severe low red blood cell count due to destruction of red blood cells (microangiopathic hemolytic anemia or MAHA) and low platelet count (thrombocytopenia) in a previously healthy individual.^[1][2] Due to earlier diagnosis and improved treatments, fewer people with acquired TTP become critically ill. TTP affects the central nervous system and/or gastrointestinal system in over 1/3 of cases. Kidneys may also be damaged by TTP, but severe kidney damage is no longer common. Other organs such as the heart may be affected, but the lungs are rarely affected.^[1]  

Thrombotic thrombocytopenic purpura, acquired (acquired TTP) is diagnosed by medical history, a thorough physical exam, and blood tests. Medical history suggestive of TTP might include having had certain diseases or conditions, such as cancer, HIV, lupus, or recent infections (or recent pregnancy), all of which can be triggers for the onset of TTP. Certain medications, quinine, chemotherapy and procedures like bone marrow transplants may also trigger the onset of acquired TTP. Physical exam would look for the signs and symptoms of acquired TTP. Blood tests will measure platelet and red and white blood cell counts, rule out other causes of anemia, and check kidney function. Special blood test assays can be used to check the level of activity of the ADAMTS13 enzyme and for the presence of the ADAMTS13 antibody inhibitor.^[1][2]

The main treatment for people with thrombotic thrombocytopenic purpura, acquired (acquired TTP) is daily plasma exchange (PEX or plasmaphoresis).^[1][2][4] PEX removes antibodies (proteins) from the blood that damage the ADAMTS13 enzyme and replaces the ADAMTS13 enzyme.^[1] Corticosteroids are usually given in addition to PEX. Some doctors may also give rituximab, but others use this medication only in cases that are not responding to treatment well or are more severe. Both corticosteroids and rituximab help slow or stop the making of the antibody which is attacking the ADAMTS13 enzyme, but both medications can have serious long term side effects. PEX is recommended to be continued daily until the platelet count has returned to normal. Once the person continues to be stable, corticosteroids will be decreased over a 2-3 week period. Since relapses can occur, doctors will continue to check for signs of TTP, especially during the first several years after an episode.^[2][4]

In about 10% of cases, acquired TTP does not respond well to these treatments. Other medications including certain chemotherapy drugs may be tried, or the doses of the corticosteroids may be increased. As medical researchers continue to learn more about the antibodies that attack the ADAMTS13 enzyme, new treatments are being developed.^[2][4]