What is Plasmapheresis?
It is the name given to a process that purifies blood in the human body. The process is performed for treating various autoimmune disorders.
This procedure is also known as Therapeutic Plasma Exchange.
In a typical session involving this procedure, a venous catheter is implanted into the body of a patient. It is then attached to a plasmapheresis machine. As the blood is drawn out, an anti-coagulating (anti-clotting) agent is used to keep it from clotting outside the human body. Once the red blood cells are spun, they are returned.
In certain cases, the plasma is treated and returned afterwards whereas they may be discarded in other cases and substituted with fresh plasma. If the plasma is being gathered up for donation, it is drawn and stored into sterile package.
Replacement or reinfusion with human plasma can give rise to a dangerous allergic reaction known as Anaphylaxis. All procedures may give rise to rashes, chills, fever and even a mild allergic reaction. The patient also has the risk of getting a bacterial infection, particularly when a central venous catheter is introduced.
In some individuals, the citrate anticoagulant may give rise to reactions like numbness and cramps. However, this generally resolves on its own. Individuals with impaired function of kidneys may require medical treatment to avert the negative effects of citrate metabolism.
Plasma consists of coagulating agents or chemicals that let the blood coalesce to form a solid clot. Exchange of plasma removes these. It is only rarely that bleeding complications follow Plasmapheresis. These may need replacement of clotting agents.
Plasmapheresis is used for effective cure of certain conditions on a temporary basis. These disorders include:
- Myasthenia Gravis – It is an autoimmune disease that results in weakness of the muscles.
- Guillain-Barré Syndrome – It is an acute neurological disease that is often followed by a viral infection which gives rise to progressive muscular fatigue and even paralysis. Read more on Guillain-Barre Syndrome..
- Chronic Inflammatory Demyelinating Polyneuropathy – This is a chronic neurological condition resulting from a destruction of the myelin sheath (medullary sheath) of peripheral nerves that gives rise to symptoms similar to Guillain-Barré Syndrome.
- Thrombotic Thrombocytopenic Purpura – It is a rare blood disease that affects only a few people.
- Hyperviscosity – This condition is characterized by extreme thickness of blood.
- Paraproteinemic Peripheral Neuropathies – This is a neurological syndrome that affects the peripheral nerves of the human body.
Plasmapheresis also has beneficial effects on other conditions. The positive effects of this procedure are generally noticed within a few days. Usually, effects can last up to a few months and not for a longer period. However, this process can make changes last for a longer period, possibly by causing changes in response of the immune system.
It is the machine used to carry out this procedure. The plasma of a person can be removed with the aid of this equipment. The machine uses a device known as a Cell Separator that divides plasma from the fluid part of the human blood. The white and red blood cells are returned. The plasma is disposed off and substituted with other fluids. This machine can successfully perform procedures like Continuous Flow Centrifugation, Plasma Filtration and Discontinuous Flow Centrifugation.
It is a process by which constituents of plasma that are supposed to cause or aggravate disorders are selectively removed. The remaining components of blood are then mixed with plasma substitute or an inert replacement and given back to the patient. Blood components that are removed may include immune complexes, lipids, antibodies, toxins, mediators of complement activation or inflammation. Molecules, that are supposed to be potentially harmful, are also removed.
This procedure is used for treating many autoimmune diseases with different success rates. Typically, the process is used to rapidly lessen immune complexes or circulating antibodies during autoimmune conditions. The method is frequently used along with other immunosuppressive therapies that help to enhance its beneficial effects or make them more long-lasting.
Therapeutic Plasmapheresis Indications
The presence of any of these conditions must indicate doctors that TPE must be chosen as a logical therapeutic choice.
The substance that is to be taken out must have a long enough half-life. This will make extracorporeal removal much more rapid than endogenic clearance tracts.
The matter that is to be withdrawn should be large enough to be difficult to remove easily by less costly purification methods such as high-flux hemodialysis or hemofiltration. The molecule weight should be higher than 15,000.
The materials that require to be dispatched must be severely toxic and resistant to mainstream therapy. This will indicate rapid removal by TPE from the extracellular fluid.
Plasmapheresis and Multiple Sclerosis
The purpose of this procedure is to eliminate antibodies from human blood and preventing them from assaulting their intended targets. In people with multiple sclerosis, the antibodies target the own body cells of the person. Plasmapheresis does not alter the behavior of antibodies but only removes them. It thus serves as a temporary solution to a permanent problem. It is due to this reason that Plasmapheresis is usually the best method for treating chronic disorders in which the symptoms become highly acute and the process is supposed to be life-saving.
90% of the disorders that can benefit from Plasmapheresis are neurological. The treatment can be highly effective and beneficial to individuals suffering from a recurring case of Multiple Sclerosis, generally after intravenous steroids have been found to be unsuccessful in bringing about any improvement.
Plasmapheresis and Myasthenia Gravis
This method is found to bring about a therapeutic effect in sufferers of Myasthenia Gravis, an acquired autoimmune syndrome that is clinically marked by symptoms like fatigue of skeletal muscles and tiredness on exertion.
The cost of Plasmapheresis is quite high. Per session of this method can cost anywhere between five thousand and ten thousand dollars in the United States. In some cases, this process may be required to be carried out repeatedly. It will help if you have a medical insurance to take care of the costs.
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Written by Shoummojit
on August 8th, 2011. The article was last updated on September 5th, 2011