Transfusion reactions (CH)

Question 1

Why are blood transfusions usually safe? (2)

Answer 1

• due to extensive screening
• pre-transfusion testing

Question 2

What are the thresholds for blood transfusions in patients with vs without ACS?

Answer 2

Non-urgently these are transfused over 90-120 minutes:

• with ACS = 80g/L
• without ACS = 70g/L

Question 3

What are adverse events in blood transfusions mediated by?

Answer 3

Interaction of recipient antibodies to foreign antigens contained in blood product

Question 4

How can immune-mediated transfusion reactions be classified?

Answer 4

• acute - occur within 24h of transfusion
• delayed - occurs days to weeks after transfusion

Question 5

What are some examples of acute transfusion reactions? (4)

Answer 5

• acute haemolytic
• allergic/anaphylaxis
• febrile non-haemolytic
• TRALI: transfusion-related acute lung injury

Question 6

What are acute transfusion reactions usually due to?

Answer 6

Clerical error - identification is critical because of the high probability of a second patient receiving the wrong blood product at the same time

Question 7

What are some examples of delayed transfusion reactions?

Answer 7

• delayed haemolytic transfusion reactions
• GvHD
• post-transfusion purpura

Question 8

What are some non-immune-mediated transfusion reactions? (4)

Answer 8

• TACO: transfusion-associated circulatory overload
• infective reaction
• transfusion-associated sepsis
• haemolysis

Question 9

What is an acute haemolytic transfusion reaction?

Answer 9

Result of ABO-RBC incompatibility –> leads to RBC (transfused) destruction by IgM antibodies

Question 10

What are the clinical features of acute haemolytic transfusion reaction? (8)

Answer 10

• fever + rigors
• tachycardia
• hypotension
• abdominal/chest pain
• dark urine
• headaches
• N&V
• agitation/anxiety (within a few mins)

Question 11

How can we investigate an acute haemolytic transfusion reaction? (3)

Answer 11

Positive Direct Coomb’s test (antiglobulin test; may be negative if all cells rapidly destroyed)

Haemoglobinuria

Repeat ABO testing

Question 12

How do we manage an acute haemolytic transfusion reaction? (3)

Answer 12

• stop transfusion
• confirm diagnosis - check ID, cross-match and blood typing, Coomb’s test
• supportive care - fluid resuscitation, urine output goal >100mL (can elicit forced diuresis with IV mannitol)

Question 13

What are some complications of acute haemolytic transfusion reactions? (3)

Answer 13

• DIC
• renal failure
• severe hypotension

Question 14

What is an allergic/anaphylactic transfusion reaction?

Answer 14

Hypersensitivity reactions to allergens in the transfused component

Question 15

In which patients is an anaphylaxis transfusion reaction common in?

Answer 15

IgA deficiency patients who have anti-IgA antibodies

More common with plasma-rich blood products e.g. FFP, cryoprecipitate and platelets

Question 16

What are the clinical features of a minor allergic transfusion reaction?

Answer 16

Pruritus and urticaria

(Urticaria without anaphylaxis)

Question 17

What are the clinical features of allergic/anaphylactic transfusion reactions? (5)

Answer 17

• hypotension
• dyspnoea
• wheezing
• angioedema
• stridor

Question 18

How can we investigate anaphylactic transfusion reaction?

Answer 18

Serum IgA & IgA antibody screen

Question 19

How can we manage a minor allergic transfusion reaction? (3)

Answer 19

• temporarily stop/slow transfusion
• antihistamine (chlorphenamine)
• monitor

Question 20

How can we manage an anaphylactic transfusion reaction? (4)

Answer 20

• stop transfusion
• IM adrenaline
• ABC support - oxygen, fluids, antihistamine, bronchodilators, corticosteroids
• glucagon if patient takes beta-blockers (may be resistant to adrenaline - refractory bradycardia and hypotension)

Question 21

What is a non-haemolytic febrile transfusion reaction?

Answer 21

Immune-mediated –> often the result of sensitisation by previous pregnancies or transfusions

Antibodies reacting with WBC fragments in blood product (HLA antibodies) and cytokines that have leaked from blood cell during storage

Question 22

What are the clinical features of non-haemolytic febrile transfusion reactions? (3)

Answer 22

• fevers
• chills
• otherwise systemically well

Question 23

How do we manage non-haemolytic febrile transfusion reactions? (3)

Answer 23

• slow / stop transfusion
• antipyretic - IV/PO paracetamol
  
  • if paracetamol reduces temperature appropriately, it is safe to restart transfusion at slower rate and increase subsequent frequency of observations
• monitor

Question 24

What is TRALI (transfusion-related acute lung injury)?

Answer 24

Non-cardiogenic pulmonary oedema secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood

Granulocyte activation in pulmonary vasculature –> increased vascular permeability

Question 25

What are the clinical features of TRALI? (6)

Answer 25

- hypoxia - dyspnoea / tachypnoea - fever - hypotension - cough - unchanged JVP

Question 26

What investigation do we do for TRALI and what do we see?

Answer 26

CXR - pulmonary infiltrates (pulmonary oedema) and 'white out'

Question 27

How do we manage TRALI?

Answer 27

SOS: - Stop transfusion - Oxygen + possible ventilation - Supportive care

Question 28

What is a delayed haemolytic transfusion reaction?

Answer 28

Non-preventable, result of amnestic antibody response to non-ABO red cell antigens that have been sensitised to (previous pregnancy, transfusion or transplantation)

Question 29

What are the clinical features of delayed haemolytic transfusion reaction? (4)

Answer 29

- fever - anaemia - jaundice (weeks after) - haemoglobinuria - red urine, due to extravascular haemolysis

Question 30

How do we investigate a delayed haemolytic transfusion reaction?

Answer 30

Positive Direct Coomb's test (may be negative if all cells rapidly destroyed; antiglobulin test)

Question 31

What are some complications of a delayed haemolytic transfusion reaction? (2)

Answer 31

- renal failure - DIC

Question 32

What is transfusion-associated GvHD?

Answer 32

Mainly in immunodeficient patients (leukaemia, lymphoma or congenital) or immunocompetent patients who are heterozygous for an HLA haplotype for which the donor is homozygous Transfused WBC react with recipient antigens

Question 33

What are the clinical features of transfusion-associated GvHD? (5)

Answer 33

- maculopapular rash - (often neck, palms and soles) --> erythroderma or toxic epidermal necrolysis-like syndrome - fever - diarrhoea (8-10 days after) - jaundice - N&V

Question 34

How do we manage transfusion-associated GvHD?

Answer 34

Supportive care

Question 35

What is a complication of transfusion-associated GvHD?

Answer 35

Leads to marrow aplasia --> death

Question 36

How do we prevent transfusion-associated GvHD?

Answer 36

Use irradiated blood products

Question 37

What is post-transfusion purpura?

Answer 37

Result of prior sensitisation to foreign platelet antigen, usually during pregnancy ITP that occurs after transfusion of a platelet-containing component (platelets, RBCs, granulocytes) where both antigen-positive donor platelets and antigen-negative recipient platelets are destroyed

Question 38

What are the clinical features of post-transfusion purpura? (3)

Answer 38

- disseminated purpura - bleeding from mucus membranes - GI tract and urinary bleeding

Question 39

How do we manage post-transfusion purpura?

Answer 39

IV Ig (correct thrombocytopenia)

Question 40

What is transfusion-associated circulatory overload (TACO)?

Answer 40

Excessive rate of transfusion in someone with pre-existing heart failure

Question 41

What are the clinical features of transfusion-associated circulatory overload (TACO)? (5)

Answer 41

- raised JVP - pulmonary oedema (crackles at bilateral lung bases) - HYPERtension - S3 - afebrile

Question 42

What is the key way to distinguish TACO from TRALI?

Answer 42

HYPERtension in TACO, HYPOtension in TRALI

Question 43

How do we manage TACO? (3)

Answer 43

- stop transfusion - IV furosemide (loop diuretic) - oxygen

Question 44

What is an infective transfusion reaction?

Answer 44

Transmission of vCJD which has been mitigated by leucodepletion, FFP etc Prion or proteinacous infectious particles are the misshaped proteins responsible for causing transmissable spongiform encephalopathies or prion diseases

Question 45

What are the clinical features of infective transfusion reaction? (8)

Answer 45

- psychiatric, behavioural changes - pain - memory impairment - visual disturbances - myoclonus - ataxia - language/hearing problems - movement dysfunction

Question 46

What investigations can be done for infective transfusion reaction? (3)

Answer 46

- MRI - high sensitivity - EEG - CSF findings

Question 47

How do we manage infective transfusion reaction?

Answer 47

No cure BZ/antidepressant, antipsychotics, anticonvulsants, SSRI, hypnotic, analgesic

Question 48

What is an ominous sign necessitating the stopping of a transfusion?

Answer 48

Hypotension

Question 49

What test confirms haemolysis?

Answer 49

Coomb's test Other tests - unconjugated BR, haptoglobin, serum and urine free Hb