What is the likely cause of a fever and shock reaction during the transfusion of platelets?

Bacterial contamination is a well-recognized complication associated with platelet transfusions, primarily because platelets are stored at room temperature, which can promote bacterial growth. If contaminated platelets are transfused, the patient may develop a rapid onset fever and septic shock due to the introduction of bacterial toxins into the bloodstream, triggering a harmful immune response. This can potentially escalate quickly, making it a critical concern during transfusions.

In contrast, other options may lead to different reactions. Allergic reactions usually manifest with mild symptoms such as itching or hives but are not typically associated with fever or shock. Febrile non-hemolytic transfusion reactions generally result in fever but do not lead to shock and are associated with leukocyte incompatibility rather than bacterial presence. Circulatory overload would primarily cause symptoms related to fluid overload, such as pulmonary edema, rather than fever and shock. Therefore, bacterial contamination is the most likely cause of the described symptoms during a platelet transfusion.