SN7 SHORT NOTE 5M

Describe the hazards of blood transfusion.

Pathology · 2nd Professional — Para-Clinical

Definition

Blood transfusion is the intravenous administration of whole blood or its components, and its hazards are divided into immunological, infective and other.

Immunological Hazards

Reaction	Mechanism	Features and management
Acute haemolytic reaction	ABO incompatibility — preformed IgM; type II hypersensitivity; almost always a clerical error	Fever, loin pain, hypotension, haemoglobinuria, DIC, renal failure. Stop the transfusion immediately, maintain the airway and circulation, and return the unit
Delayed haemolytic reaction	Anamnestic response to a minor antigen (Rh, Kidd) 5–10 days later	Falling haemoglobin, jaundice, positive direct Coombs test
Febrile non-haemolytic reaction	Antibodies to donor leucocytes; the commonest reaction	Fever and rigors; prevented by leucodepletion
Allergic / anaphylactic	Antibodies to plasma proteins; anaphylaxis in IgA-deficient recipients	Urticaria to full anaphylaxis; washed cells for IgA deficiency
TRALI (transfusion-related acute lung injury)	Donor anti-leucocyte antibodies activating recipient neutrophils in the lung	Acute dyspnoea and pulmonary oedema within 6 hours, with a normal jugular venous pressure
TACO (transfusion-associated circulatory overload)	Volume overload	Dyspnoea with a raised jugular venous pressure; responds to diuretics
Transfusion-associated GVHD	Viable donor lymphocytes in an immunosuppressed recipient	Rash, diarrhoea, jaundice and marrow aplasia; mortality over 90%; prevented by irradiating the product
Post-transfusion purpura	Anti-HPA-1a antibodies	Severe thrombocytopenia about a week later

CLINICAL PEARL

TRALI and TACO both cause breathlessness during transfusion, and the jugular venous pressure separates them. TACO is overload, so the JVP is raised and diuretics help. TRALI is capillary leak, so the JVP is normal and diuretics are harmful. Getting this wrong at the bedside does real damage.

Infective Hazards

Viral — HIV, hepatitis B and C (the chief concerns, now much reduced by screening and nucleic acid testing, but not eliminated because of the window period); cytomegalovirus; HTLV; parvovirus B19
Bacterial — contamination, particularly of platelets, which are stored at room temperature; causes fulminant septic shock
Parasitic — malaria, an important risk in India; also babesiosis, Chagas disease, kala-azar
Syphilis — rare, since the organism does not survive refrigeration

Other Hazards

Massive transfusion (replacement of one blood volume in 24 hours) — coagulopathy from dilution, hypothermia, citrate toxicity with hypocalcaemia, hyperkalaemia, and acid–base disturbance
Iron overload in the chronically transfused — thalassaemia, myelodysplasia; each unit contains about 200 mg of iron
Alloimmunisation, making future cross-matching progressively harder
Immunomodulation, with a possible increase in postoperative infection

Applied Aspects

The commonest serious hazard is a clerical error, not an exotic reaction — checking the patient’s identity against the unit at the bedside is the single most important safety step
Transfuse components, not whole blood, and transfuse for a clinical indication rather than a threshold figure
Irradiated products for severely immunosuppressed patients, after purine analogues, for intrauterine and neonatal exchange transfusion, and for directed donations from relatives
Voluntary non-remunerated donation is the safest source; paid and replacement donation carries a higher infection risk, which is why India has moved against it
Haemovigilance — every reaction should be reported, since systematic reporting is how transfusion safety has improved
Consent and documentation are required, and the indication should be recorded in the notes

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