Sunday, June 29, 2008

Causes and Symptoms of Blood Transfusion Reaction

What is this Condition? Transfusion reaction accompanies or follows intravenous administration of blood components. Its severity varies from mild (fever and chills) to severe (acute kidney failure or complete vascular collapse and death), depending on the amount of blood transfused, the type of reaction, and the person's general health.

What Causes it? Hemolytic reactions (red blood cell rupture) follow transfusion of mismatched blood. Transfusion with incompatible blood triggers the most serious reaction, marked by intravascular clumping of red blood cells. The recipient's antibodies (immunoglobulin G or M) adhere to the donated red blood cells, leading to widespread clumping and destruction of the recipient's red blood cells and, possibly, the development of disseminated intravascular coagulation and other serious effects.

Transfusion with Rh-incompatible blood triggers a less serious reaction within several days to 2 weeks. Rh reactions are most likely in women sensitized to red blood cell antigens by prior pregnancy or by unknown factors, such as bacterial or viral infection, and in people who have received more than five transfusions.

Allergic reactions are fairly common but only occasionally serious. Febrile nonhemolytic reactions, the most common type of reaction. apparently develop when antibodies in the recipient's plasma attack antIgens.

Bacterial contamination of donor blood, although fairly uncommon, can occur during donor phlebotomy. Also possible is contamination of donor blood with viruses (such as hepatitis), cytomegalovirus, and the organism causing malaria.

What are its Symptoms? Immediate effects of hemolytic transfusion reaction develop within a few minutes or hours after the start of transfusion and may include chills, fever, hives, rapid heartbeat, shortness of breath, nausea, vomiting, tightness in the chest, chest and back pain, low blood pressure. bronchospasm, angioedema, and signs and symptoms of anaphylaxis, shock, pulmonary edema, and congestive heart failure. In a person having surgery under anesthesia, these symptoms are masked, but blood oozes from mucous membranes or the incision.

Delayed hemolytic reactions can occur up to several weeks after transfusion, causing fever, an unexpected decrease in serum hemoglobin, and jaundice.

Allergic hemolytic reactions typically don't cause a fever and are characterized by hives and angioedema, possibly progressing to cough, respiratory distress, nausea and vomiting, diarrhea, abdominal cramps, vascular instability, shock, and coma.

The hallmark of febrile nonhemolytic reactions is a mild to severe fever that may begin when the transfusion starts or within 2 hours after its completion.

Bacterial contamination causes high fever, nausea and vomiting, diarrhea, abdominal cramps and, possibly, shock. Symptoms of viral contamination may not appear for several weeks after transfusion.

How is it Diagnosed? Confirming a hemolytic transfusion reaction requires proof of blood incompatibility and evidence of hemolysis. When such a reaction is suspected, the person's blood is retyped and crossmatched with the donor's blood.

When bacterial contamination is suspected, a blood culture should be done to isolate the causative organism.

How is it Treated? At the first sign of a hemolytic reaction, the transfusion is stopped immediately. Depending on the nature of the person's reaction, the health care team may:

- monitor vital signs every 15 to 30 minutes, watching for signs of shock

- maintain an open intravenous line with normal saline solution, insert an indwelling urinary catheter, and monitor intake and output

- cover the person with blankets to ease chills

- deliver supplemental oxygen at low flow rates through a nasal cannula or hand-held resuscitation bag (called an Ambu bag)

- administer drugs such as intravenous medications to raise blood pressure and normal saline solution to combat shock, Adrenalin to treat shortness of breath and wheezing, Benadryl to combat cellular histamine released from mast cells, corticosteroids to reduce inflammation, and Osmitrol or Lasix to maintain urinary function. Parenteral antihistamines and corticosteroids are given for allergic reactions (arlaphylaxis, a severe reaction, may require Adrenalin). Drugs to reduce fever are administered for febrile nonhemolytic reactions and appropriate intravenous antibiotics are given for bacterial contamination.

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