Which finding is a manifestation of a hemolytic transfusion reaction?

A hemolytic transfusion reaction occurs when the recipient's immune system attacks the transfused red blood cells, leading to their destruction (hemolysis). One of the classic symptoms associated with this type of reaction is low back pain. This pain is thought to arise from the kidneys, where the breakdown of red blood cells occurs, and can be a result of acute hemolysis leading to the release of hemoglobin into the urine, causing kidney irritation and discomfort.

Other symptoms of a hemolytic transfusion reaction may include fever, chills, nausea, and hypertension. However, the presence of low back pain is particularly characteristic and often emphasizes the severity of the reaction, giving clinicians a crucial indicator for diagnosis and management. The mechanism behind this pain is directly related to the physiological responses triggered during the immune response to the transfused blood components.