Blood Transfusion Complications

Question 1

A patient develops hypotension, tachycardia, tachypnea, fever, chills, chest/flank pain, and red or brown urine soon after receiving a blood transfusion of packed RBC. What is going on?

Answer 1

acute hemolytic transfusion reaction: 0-60mins, medical emergency

due to ABO incompatibility —> destruction of donor RBC by recipient isoagglutinin IgM —> intravascular hemolysis of transfused cells

(via complement activation by IgM —> Type II hypersensitivity)

Question 2

what is the mechanism and outcome of acute hemolytic transfusion reaction?

Answer 2

Type II hypersensitivity due to ABO mismatch

recipient IgM isoagglutinins activate complement —> intravascular hemolysis of donor RBC

activation of Factor XII (12, intrinsic pathway) —> thrombus formation, DIC

renal failure - ischemia and hemoglobin toxicity (tubular obstruction, proximal tubule injury, vasoconstriction)

Question 3

when should you expect acute hemolytic transfusion reaction and how can you diagnose it?

Answer 3

FEVER, dyspnea, hypotension, hemoglobinuria, DIC

diagnosis: plasma is pink, POSITIVE direct Coombs test, blood in urine

Question 4

describe what causes delayed hemolytic transfusion reaction

Answer 4

3-30 days post-transfusion

anamnestic (memory) response by secondary exposure to previously encountered antigen (prior transfusion, transplantation, pregnancy)

antibody are usually Kidd or Rh system (IgG) - undetectable on screening

extravascular (spleen) hemolysis

Question 5

in delayed hemolytic transfusion reaction, hemolysis that occurs is:
a. intravascular
b. extravascular

Answer 5

b. extravascular - spleen

secondary exposure to previously encountered antigen

antibody are IgG

Question 6

what clinical signs are seen with delayed hemolytic transfusion reaction?

Answer 6

mild jaundice (unconjugated bilirubin), slight fever

spherocytosis

POSITIVE direct Coombs test (due to IgG antibodies against previously encountered antigen not detected by screening)

Question 7

what causes febrile non-hemolytic transfusion reaction?

Answer 7

cytokines generated during transfusion storage —> leukocyte related (WBC)

usually benign, symptoms 1-6hours later - fever, headache, chills, but must exclude other causes

Question 8

describe how transfusion-related acute lung injury presents

Answer 8

sudante onset of acute hypoxemia - within minutes, up to 6h later

tachypnea, dyspnea, cyanosis, NO signs of heart failure (non-cardiogenic pulmonary edema)

pulmonary infiltrates on chest X-ray (CXR)

Question 9

what triggers transfusion related acute lung injury?

Answer 9

student onset of acute hypoxemia

first hit: trigger, primes neutrophils (sepsis, malignancy, shock, surgery)

second hit: antibody in donor unit binds to primed PMNs —> endo/epithelial damage and pulmonary edema

Question 10

what possibly must you exclude before diagnosis TRALI (transfusion-related acute lung injury)?

Answer 10

must exclude transfusion-associated circulatory overload, when too much transfusion volume is given too soon and it overwhelms the heart —> heart failure

*remember that TRALI will NOT present with signs of heart failure - non-cardiogenic pulmonary edema

Question 11

what is the mechanism of urticarial transfusion reaction?

Answer 11

type I hypersensitivity - hives, reaction to allergen in the plasma triggering pre-existing IgE —> mast cell/basophil degranulation

transfusion can be continued after treatment

(note that anaphylactic transfusion reaction is a medical emergency - STOP transfusion)