Acute Hemolytic Transfusion Reaction

Acute Hemolytic Transfusion Reaction is a serious condition that occurs when the body's immune system attacks transfused red blood cells. This reaction primarily affects the blood and immune system and can cause symptoms such as fever, chills, and back pain shortly after a blood transfusion. The immune system mistakenly identifies the transfused blood cells as harmful and destroys them rapidly, leading to a sudden drop in red blood cells. This destruction can cause problems like shortness of breath, low blood pressure, and dark urine. The condition requires immediate medical attention because it can lead to severe complications affecting the kidneys and other organs. Understanding this reaction helps explain why blood transfusions must be carefully matched and monitored.

Acute Hemolytic Transfusion Reaction (AHTR) is an immune-mediated destruction of transfused red blood cells occurring within 24 hours of transfusion. It is most commonly caused by ABO incompatibility due to preformed recipient antibodies against donor red blood cell antigens. The core pathology involves complement activation leading to intravascular hemolysis, releasing free hemoglobin and causing systemic inflammatory responses. Clinically, AHTR presents with fever, chills, hypotension, flank pain, and hemoglobinuria. This reaction can result in acute kidney injury, disseminated intravascular coagulation (DIC), and shock. Prompt recognition is critical due to its potential for rapid progression and high morbidity. Laboratory findings include a positive direct antiglobulin test (DAT) and evidence of hemolysis such as elevated lactate dehydrogenase (LDH) and decreased haptoglobin.