This is the fourth part of our series about the condition based on our patient booklet “Fast Facts for Patients: Thrombotic Thrombocytopenic Purpura”. This article focuses on the treatment for immune thrombotic thrombocytopenic purpura (iTTP) in the form of plasma exchange.

 

The most important initial treatment for acute iTTP is plasma exchange, which is carried out by a specially trained nurse (apheresis nurse) using a machine called a cell separator. This separates the liquid plasma from the blood cells and replaces it with healthy donor plasma (containing the missing ADAMTS13 enzyme) before the blood passes back into the body.

Before the procedure, a small, thin tube is inserted into a large vein, either in your leg (groin) or neck, to allow blood to flow to the cell separator. This is inserted under local anesthetic (to numb the area). To stop blood clotting in the machine, an anticoagulant called ACDA is passed into the plasma and may cause low calcium levels in the body.

Cell separator for treating TTP.

Each plasma exchange procedure normally takes 2–5 hours, and one or two procedures per day are usually needed in the first few days after admission to hospital, until the platelet count returns to normal. Plasma exchange can be carried out at your bedside on the ward.

Plasma exchange is very safe. The plasma used is taken from healthy donors and screened to minimize the risk of any infection. It is specially treated to kill viruses, such as hepatitis C virus.

An anticoagulant is something that stops the blood from clotting. The process of blood clot formation is also known as coagulation.

 

Plasma exchange treatment for iTTP.

 

Possible Side Effects

  • The shift of fluid when plasma is being removed and then replaced can sometimes cause low blood pressure, leading to dizziness and/or feeling faint. It is important to rest for at least 20 minutes after the procedure, and to avoid moving too quickly.
  • Some people are very sensitive to ACDA and their calcium levels drop very quickly. Calcium is given to correct this, either as tablets or intravenously (through a cannula, which is a small plastic tube, into a vein in the arm).
  • Because plasma contains other proteins apart from ADAMTS13, it is possible to have allergic reactions. These can include an itchy rash or, very rarely, a feeling of swelling in the tongue, irritation of the nasal passages, wheezing, cough or breathlessness. If you have an allergic reaction during the exchange, we will give you medication to treat it.

Practical Tips

  • It is important that you rest for at least 20 minutes after the plasma exchange procedure and avoid moving too quickly.
  • Let the apheresis nurse know if you have pins and needles in your nose, face, hands or body, or you can feel a vibration in your chest. Your calcium level may have dropped and will need to be checked.

 

Please check out the other posts of our series here:

 

Information based on Fast Facts for Patients: Thrombotic Thrombocytopenic Purpura (Karger, 2022).

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