Hematology: Transfusion Reactions

Electrolyte Abnormalities

• Hypocalcemia – Citrate Chelation After Massive Transfusion
• Hyperkalemia – High Potassium Concentration in Stored PRBC (Due to Lysis During Storage)
• Metabolic Alkalosis – Citrate is Metabolized to Bicarbonate

Mild Allergic (Urticarial) Reaction

• Cause: Host IgE Reacts to Soluble Substances in Donor Plasma
  • Initiates Release of Histamine by Mast Cells & Basophils
• Timing: 2-3 Hours
• Presentation: Urticaria (Hives) & Pruritis
• Clinical Diagnosis
• Treatment: Diphenhydramine (Benadryl)
  • Should Stop Transfusion – But Can Resume if Urticaria Improves

Anaphylaxis

• Cause: Sudden Massive Release of Histamine by Mast Cells & Basophils
  • Allergy to Transfusion Contents (IgE or IgG-Mediated Immune Reaction)
  • Host Antibody to Donor IgA (Seen in IgA Deficiency Patients)
• Timing: Seconds-Minutes
• Presentation:
  • Bronchospasm/Wheezing
  • Shock
  • Angioedema
• Clinical Diagnosis
• Treatment: Epinephrine & Stop Transfusion

Febrile Nonhemolytic Transfusion Reaction (FNHTR)

• The Most Common Transfusion Reaction
• Cause: Host Antibody to Donor Cytokines
  • Prevent by Leukoreduction
• Timing: Minutes-Hours
• More Common After PRBC and Platelet Transfusions than Plasma
  • Highest Risk with Whole Blood-Derived Platelets (Compared to Apheresis)
• Presentation:
  • Fever
  • Chills/Rigors
• Clinical Diagnosis
• Treatment: Stop Transfusion

Acute Hemolytic Transfusion Reaction

• Cause: Hemolysis Due to ABO Incompatibility (Host Antibody to Donor RBC)
• Timing: < 24 Hours
• Presentation:
  • “Classic Triad”: Rarely Seen
    • Fever
    • Flank Pain
    • Hemoglobinuria (Red Urine)
  • Acute Tubular Necrosis (ATN)
  • Disseminated Intravascular Coagulation (DIC)
• Treatment: Stop Transfusion, Aggressive Fluid Resuscitation (Normal Saline) & Hemodynamic Support
  • Medical Emergency
  • Goal Urine Output > 1 cc/kg/Hour
  • Consider Diuresis if Hemodynamically Stable with Signs of Overload

Transfusion-Related Acute Lung Injury (TRALI)

• Definition: New Acute Lung Injury/ARDS Occurring within 6 Hours of Transfusion
• Cause:
  • Host Neutrophils are Sequestered in the Lung Microvasculature
  • Host Neutrophils are Activated by Donor Factors Causing Release of Inflammatory Mediators & Pulmonary Edema
    • Can Be Caused by Donor Antibodies Against Host Leukocytes
• Timing: < 6 Hours
• Presentation:
  • Pulmonary Edema
  • Hypoxemia
  • Fever
  • Pink Frothy Airway Secretions
• Most Common Cause of Death after Transfusion
• Treatment: Stop Transfusion & Hemodynamic Support
  • Most Will Require Ventilatory Support (70-80%)
  • Utilize Lung Protective Strategy for Ventilation – Similar to ARDS

Transfusion-Associated Circulatory Overload (TACO)

• Definition: At Least 3 of the Following within 12 Hours of Transfusion
  • Respiratory Distress
  • Pulmonary Edema
  • Elevated BNP
  • Other Unexplained Cardiovascular Changes
• Cause: Pulmonary Edema Due to Circulatory Volume Overload
  • Most Common After a Large Volume Transfusion with Underlying Heart Failure
• Timing: < 12 Hours
• Presentation:
  • Respiratory Distress
  • Headache
• Treatment: Stop Transfusion, Diuretics & Hemodynamic Support
  • May Require Ventilatory Support

Infection/Sepsis

• Due to Transfusion of Infected Blood Products
• Timing: 9-24 Hours
• Microbiology:
  • Bacterial Infection More Common Than Viral Infection
  • Most Common Organism: Gram Negative Rods (Escherichia coli, etc.)
  • HIV & Hepatitis Carry a Risk in All Transfusions Except Albumin & Serum Ig
    • Heat Treated Prior to Packaging
• Donated Blood is Screened For: HIV, HBV, HCV, HTLV, Syphilis & West Nile Virus
• Most Common Source: Platelet Transfusion (Stored at Room Temperature)
• Presentation:
  • Fever
  • Chills
  • Hemodynamic Instability
• Treatment: Antibiotics & Hemodynamic Support

Post-Transfusion Purpura (PTP)

• Cause: HPA-1a Platelet Antibody
  • Must Have Been Previously Sensitized – Pregnancy or Transfusion
• Usually Presents 5-12 Days After Transfusion
• Presentation:
  • Thrombocytopenia (Often Severe < 15,000-20,000)
  • Profound Bleeding
  • Purpura
• Diagnosis: HPA-1a Antibody Testing
• Treatment: IVIG
  • Platelet Transfusions Can Exacerbate the Disease Process