Questions
2–3 questions per clinical semester paper
Difficulty
Medium
Importance
High yield for MBBS and BMLT clinical viva
Overview
Transfusion reactions are adverse effects occurring during or after the administration of blood products. Understanding these is critical for clinical safety and exam success, as they distinguish between immediate immune-mediated events and delayed non-immune complications. Aspirants must master the categorization based on timing and pathophysiology to correctly identify and manage these emergencies.
Acute Hemolytic Transfusion Reaction (AHTR)
AHTR is the most serious reaction caused by ABO incompatibility, leading to rapid destruction of transfused red blood cells. It occurs within minutes of transfusion initiation and represents a medical emergency that requires immediate cessation of the product.
- Pathophysiology: IgM antibodies causing intravascular hemolysis
- Classic triad: Fever, flank pain, and hemoglobinuria
- Major complication: Disseminated Intravascular Coagulation (DIC)
- Management: Stop transfusion, maintain airway, aggressive IV hydration
Febrile Non-Hemolytic Transfusion Reaction (FNHTR)
This is the most common adverse reaction, characterized by a temperature rise of at least 1 degree Celsius associated with transfusion. It is primarily caused by cytokine accumulation in the stored blood or recipient antibodies against donor leukocytes.
- Definition: Rise in temperature >1 degree Celsius
- Exclusionary criteria: Requires ruling out hemolysis
- Preventive measure: Use of leukoreduced blood components
- Treatment: Antipyretics like acetaminophen
Allergic and Anaphylactic Reactions
Allergic reactions range from mild urticaria to life-threatening anaphylaxis, often caused by donor plasma proteins interacting with recipient IgE. Anaphylaxis is severe and specifically observed in patients with selective IgA deficiency who possess anti-IgA antibodies.
- Mild symptoms: Urticaria and pruritus
- Severe symptoms: Hypotension, bronchospasm, and shock
- Risk group: IgA-deficient patients
- Management: Antihistamines for mild; epinephrine for severe cases
Transfusion-Related Acute Lung Injury (TRALI)
TRALI is a leading cause of transfusion-related mortality characterized by non-cardiogenic pulmonary edema occurring within six hours of transfusion. It is thought to be triggered by donor antibodies (anti-HLA or anti-HNA) that activate neutrophils in the recipient's lung.
- Primary sign: Hypoxia and bilateral pulmonary infiltrates
- Timing: Onset within 6 hours of transfusion
- Management: Supportive oxygen therapy and ventilatory support
- Key differentiator: Absence of fluid overload indicators
Exam Tip
Always prioritize the order of action: 'Stop, Check, and Inform'—the first step in any transfusion reaction is to immediately stop the blood product infusion.
Common Mistakes
- Confusing the symptoms of AHTR with FNHTR, which leads to incorrect clinical management protocols.
- Failing to mention that TRALI is a non-cardiogenic process, often incorrectly identifying it as circulatory overload (TACO).
- Ignoring the specific risk factor of IgA deficiency when describing anaphylactic reactions.
More Revision Notes
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