BLOOD TRANSFUSION REACTIONS 

CLASSIFICATION 

A. Based on TIMING

B. Based on MECHANISM

BLOOD TRANSFUSION REACTIONS – TABLE

ACUTE TRANSFUSION REACTIONS 

1. ACUTE HEMOLYTIC TRANSFUSION REACTION (AHTR) – MOST DANGEROUS

Cause

• ABO incompatibility (most common)
• Clerical error = most common cause
• Preformed IgM antibodies → complement activation

Pathophysiology

1. Recipient anti-A/anti-B antibodies bind donor RBCs
2. Complement activation (C5–C9)
3. Intravascular hemolysis
4. Release of:
• Free hemoglobin → AKI
• Cytokines → shock
• Tissue factor → DIC

Clinical Features (CLASSIC EXAM LIST)

• Fever, chills
• Severe back/flank pain
• Chest pain
• Dyspnea
• Hypotension
• Hemoglobinuria (cola-colored urine)
• Bleeding (DIC)
• Oliguria / anuria

Investigations

Management (STEPWISE – VERY IMPORTANT)

1. STOP transfusion immediately
2. Maintain IV access with normal saline
3. Inform blood bank
4. Send:
• Patient blood
• Donor blood
• Urine sample

5. Supportive care:

• Aggressive IV fluids
• Maintain urine output (>1 mL/kg/hr)
• Loop diuretics (if needed)

6. Treat DIC if present
7. Vasopressors if shock
8. Dialysis if AKI

Prevention

• Strict bedside identity check
• Barcoding systems
• Two-person verification

2. FEBRILE NON-HEMOLYTIC TRANSFUSION REACTION (FNHTR)

Definition

• ≥1°C rise in temperature during or within 4 hours of transfusion
• No hemolysis

Pathogenesis

• Recipient antibodies against donor WBC antigens
• Cytokines (IL-1, IL-6, TNF-α) accumulated during storage

Clinical Features

• Fever
• Chills, rigors
• Malaise
• Anxiety

## Diagnosis of exclusion → rule out AHTR & sepsis first

Management

• Stop transfusion temporarily
• Paracetamol
• Restart cautiously if symptoms resolve

Prevention

• Leukoreduced blood products (most effective)

3. ALLERGIC TRANSFUSION REACTION

Cause

• Hypersensitivity to plasma proteins

Types

Mild (Urticarial)

• Itching
• Flushing
• Urticaria

Severe (Anaphylaxis) → see below

Management (Mild)

• Stop transfusion
• Antihistamines
• Restart if resolved

4. ANAPHYLACTIC TRANSFUSION REACTION

Cause

• IgA deficiency in recipient
• Anti-IgA antibodies react with donor IgA

Clinical Features

• Sudden onset
• Hypotension
• Bronchospasm
• Angioedema
• Shock
• No fever

Management

1. Stop transfusion
2. IM adrenaline
3. Airway support
4. IV fluids
5. Steroids, antihistamines

Prevention

• Washed RBCs
• IgA-deficient plasma

5. TRALI (TRANSFUSION-RELATED ACUTE LUNG INJURY)

Definition

Acute hypoxemic respiratory failure within 6 hours of transfusion without cardiac failure

Pathogenesis (TWO-HIT HYPOTHESIS)

1. Patient factors (sepsis, surgery) prime neutrophils
2. Donor anti-HLA / anti-neutrophil antibodies activate them
3. Endothelial injury → capillary leak

Clinical Features

• Acute dyspnea
• Hypoxemia
• Bilateral infiltrates
• Fever ± hypotension
• Normal JVP

Investigations

Management

• Supportive only
• Oxygen / ventilation
• No diuretics
• Avoid further transfusion from implicated donor

Prevention

• Male-only plasma
• Avoid multiparous female donors

6. TACO (TRANSFUSION-ASSOCIATED CIRCULATORY OVERLOAD)

Cause

• Rapid or excessive transfusion
• Elderly, CHF, CKD, pediatrics

Clinical Features

• Dyspnea
• Orthopnea
• Hypertension
• Raised JVP
• Pulmonary edema

Differentiation: TRALI vs TACO (VERY HIGH-YIELD)

Management

• Stop transfusion
• Sit upright
• Oxygen
• Diuretics

7. BACTERIAL TRANSFUSION-TRANSMITTED SEPSIS

Cause

• Platelets (room temperature) > RBCs
• Common organisms:
• Platelets → Staph, Strep
• RBCs → Yersinia

Clinical Features

• High fever
• Rigors
• Hypotension
• Shock
• DIC

Management

• Stop transfusion
• Broad-spectrum antibiotics
• ICU support
• Blood cultures

DELAYED TRANSFUSION REACTIONS

8. DELAYED HEMOLYTIC TRANSFUSION REACTION (DHTR)

Timeline

• 3–14 days (can be weeks)

Cause

• Anamnestic response to minor RBC antigens
  (Rh, Kidd, Duffy, Kell)

Features

• Unexplained fall in Hb
• Mild jaundice
• Fever
• Positive DAT

Management

• Usually supportive
• Avoid antigen-positive blood in future

9. TRANSFUSION-ASSOCIATED GRAFT-VERSUS-HOST DISEASE (TA-GVHD)

Cause

• Viable donor T-lymphocytes engraft and attack host tissues

Risk Groups

• Immunocompromised
• Neonates
• Intra-family transfusion
• HLA-matched transfusion

Clinical Features (CLASSIC TRIAD)

• Fever
• Skin rash
• Pancytopenia (fatal)

Prevention (ONLY EFFECTIVE MEASURE)

• Irradiated blood products

10. IRON OVERLOAD (TRANSFUSIONAL HEMOSIDEROSIS)

Seen In

• Thalassemia
• MDS
• Chronic transfusion dependence

Complications

• Liver cirrhosis
• Cardiomyopathy
• Diabetes
• Hypogonadism

Management

• Iron chelation:
• Deferoxamine
• Deferasirox

METABOLIC & OTHER TRANSFUSION COMPLICATIONS

ONE-LINE EXAM PEARLS

• Most common fatal reaction → AHTR
• Most common overall reaction → FNHTR
• Most common cause of AHTR → Clerical error
• TRALI = non-cardiogenic pulmonary edema
• TA-GVHD prevention → irradiation
• IgA deficiency → anaphylaxis
• Leukoreduction prevents → FNHTR, CMV transmission