每日一题_2023.08.15

A 34-year-old woman is brought to the emergency department in mid-August after collapsing during a picnic at a local park. She is hypotensive, tachycardic, and diaphoretic with cold extremities. Her oxygen saturation is 85% on room air. Physical examination reveals she is using accessory muscles to breathe. Which of the following is involved in the production of this patient’s symptoms?

8月中旬，一名34岁的女性在当地公园野餐时晕倒，被送到急诊室。患者血压低，心动过速，发汗，四肢发冷。在室内空气中，她的氧饱和度为85%。体格检查显示她正在使用辅助肌肉来呼吸。下列哪项与该患者症状的产生有关?

(A)  C3a

(B)  Granulocyte macrophage colony-stimulating factor

(C)  IgA

(D)  Interleukin-3

(E)  Membrane attack complex

答案解析：

低血压(四肢寒冷、湿冷、心动过速和低血压性晕厥)和呼吸障碍(缺氧和使用辅助肌肉呼吸)的临床表现表明，该女性可能处于过敏性休克状态。考虑到野餐的环境，蜜蜂蜇伤的毒液可能引发了这种反应。过敏性休克可能是由C3a和C5a与IgE结合介导的，引起组胺释放。C3通过两个C3转化酶之一转化为C3a和C3b。类似地，C5通过两个C5转化酶之一转化为C5a和C5b。C3a和C5a在血流中循环并引发过敏反应。C3a和C5a的大量释放可导致过敏性休克。

正确答案：A