Blood Transfusion Reaction
Mediated by immune or nonimmune factors, a transfusion reaction accompanies or follows I. V. administration of blood components. Its severity varies from mild (fever and chills) to severe (acute renal failure or complete vascular collapse and death), depending on the amount of blood transfused, the type of reaction, and the patient's general health.
The immune response to blood can be directed against red blood cells (RBCs), white blood cells, platelets, or one or more immunoglobulin (lg).
A hemolytic reaction follows the transfusion of mismatched blood. Transfusion with serologically incompatible blood triggers the most serious reaction, marked by intravascular agglutination of RBCs. The recipient's antibodies (lgG or IgM) attach to the donor RBCs, leading to widespread clumping and destruction of the recipient's RBCs.
Transfusion with Rh-incompatible blood triggers a less serious reaction, known as Rh isoimmunization, within several days to 2 weeks. Rh reactions are most likely to occur in women who are sensitized to RBC antigens by prior pregnancy or unknown factors, such as bacterial or viral infection, and in people who have received more than five transfusions.
A febrile nonhemolytic reaction, the most common type of reaction, apparently develops when cytotoxic or agglutinating antibodies in the recipient's plasma attack antigens on transfused lymphocytes, granulocytes, or plasma cells.
Transfused soluble antigens can react with surface IgE molecules on mast cells and basophils, causing degranulation and release of allergic mediators. Antibodies against IgA in an IgA-deficient recipient can also trigger a severe allergic reaction (anaphylaxis).
Confirmation of a hemolytic transfusion reaction requires proof of blood incompatibility and evidence of hemolysis, such as hemoglobinuria, anti-A or anti-B antibodies in the serum, decreased serum hemoglobin levels, and elevated serum bilirubin levels. A patient who is suspected of having such a reaction should have his blood retyped and cross matched with the donor's blood.
After a hemolytic transfusion reaction, laboratory tests show increased indirect bilirubin and serum hemoglobin levels, decreased haptoglobin levels, and hemoglobin in urine. As the reaction progresses, test results may be consistent with those of DIC - such as thrombocytopenia, increased prothrombin time, and decreased fibrinogen level - and signs of acute tubular necrosis - such as increased blood urea nitrogen and serum creatinine levels.
If a hemolytic reaction occurs, the transfusion should be stopped immediately. Osmotic or loop diuretics can prevent acute tubular necrosis. Other symptomatic treatment includes I.V. vasopressors and normal saline solution to combat shock, epinephrine to treat dyspnea and wheezing, diphenhydramine to combat cellular histamine released from mast cells, corticosteroids to reduce inflammation, and mannitol or furosemide to maintain urinary tract function. Dialysis may also be necessary if acute tubular necrosis occurs.
Treatment for a nonhemolytic febrile reaction calls for antipyretics.
Typing of donated blood into ABO and Rh groups has reduced the risk of transfusion reaction.
Prior to a transfusion, blood is usually crossmatched to further confirm that the blood is compatible. A small amount of donor blood is mixed with a small amount of recipient blood and the mixture is examined under a microscope for signs of antibody reaction.
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