1st Prelims: Transfusion Reactions

adverse physiological reaction to the infusion of blood

Transfusion reactions

This is a reaction that destroys the transfused blood cells in vivo, where large amounts of free hemoglobin are released into the blood and can cause systemic damage

Hemolytic

What are the types of transfusion reaction?

1. Hemolytic & Nonhemolytic

2. Acute Reaction

3. Delayed Reaction

4. Immune mediated transfusion reaction

Intravascular reactions are usually ___, whereas extravascular reactions are usually ____

acute ; delayed

What are the mechanism of hemolytic transfusion reaction?

1. Antibody binding to RBC

2. Anaphylatoxins

3. Cytokine Activation

4. Coagulation Activation

Intravascular hemolysis:

- ____ antibodies activate the ____ that lyses RBCs intravascularly.

IgM , classical pathway of complement

Extravascular hemolysis:

- Antibody-coated RBCs are removed from circulation by the ____ and ____.

liver and spleen

_____ cause hypotension by triggering release of ____ and ____

Anaphylatoxins ; serotonin and histamine

Sensitized RBCs are cleared from the blood by phagocytes. The phagocytes release cytokines that cause:

1. fever,

2. hypotension,

3. activation of T- and B cells

In the coagulation activation: Antigen-antibody-complement complexes activate the ____ and cause ____.

clotting system ; DIC

_____ is caused by systemic hypotension, reactive renal vasoconstriction, and intravascular thrombi

Renal failure

• Mechanisms:

  • Antigen-antibody reaction activates complement or coats RBCs (i.e., ABO incompatible blood and antibodies to Vel or Vel or PP1Pk antigens)

• Occurrence: 1:25,000 transfusions

• Diagnostic laboratory tests:

  • Elevated plasma free hemoglobin,

  • Elevated bilirubin (6 hours posttransfusion)

  • Decreased haptoglobin

  • Positive DAT.

Acute hemolytic transfusion reactions

Usually less severe than acute hemolytic transfusion reaction, and dependent on the concentration of antibody in the blood rather than the type of antibody

• Occurrence: 1:2,500 transfusions

• Diagnostic laboratory tests: Positive DAT, positive posttransfusion antibody screen, and decreased hemoglobin and hematocrit

Delayed hemolytic transfusion reactions

• Clinical signs

  • Fever with temperature increase 1 °C over baseline temperature 8-24 hours posttransfusion

  • Nausea, vomiting, headache, and back pain

• Causes:

  • HLA antibody in recipient to donor antigens; cytokines in blood products containing WBCs and platelets

• Occurrence

  • Common in patients with multiple pregnancies and transfusions

  • Multiple exposures to HLA antigens

  • Common in women

  • 1:200 donor units transfused

Immune-Mediated Nonhemolytic Transfusion Reaction

What are the allergic transfusion reactions?

Urticarial and Anaphylactic reactions

• Clinical signs: Wheals, hives, itching

• Sequelae: None

• Causes: Recipient forms antibodies to foreign proteins in donor plasma

• Occurs in 1-3% of recipients

Urticarial reactions

• Clinical signs:

  • Rapid onset, severe wheezing and cough, and bronchospasms

• Sequelae: Syncope, shock, death

• Cause: Genetic IgA deficiency

• Occurs very rarely

Anaphylactic reactions

• Clinical signs:

  • 3-30 days posttransfusion,

  • fever,

  • erythematous maculopapular rash,

  • abnormal liver function

• Sequelae:

  • Sepsis,

  • Hemorrhage,

  • 90% mortality rate

• Cause:

  • Transfused T cells react against recipients

• Occurs rarely

Transfusion-Associated Graft-versus-Host Disease

Bacterial contamination usually occurs during ____ or during ___ of frozen blood components.

• Bacteria (____________, most common) live and multiply in bag during storage

phlebotomy, thawing

• Yersinia enterocolitica

Too much blood in a patient's vascular system caused by transfusing a unit too fast; most often occurs in children and elderly patients

• Symptoms: Dyspnea, severe headache, peripheral edema, and signs of congestive heart failure occurring after transfusion; can be fatal

Circulatory Overload

This condition, which is characterized by the deposition of the iron-containing pigment hemosiderin in organs such as the liver and spleen, occurs in chronically transfused patients, especially those with hemolytic anemias.

Hemosiderosis