Question

Dramatic hypotension sometimes accompanies type I hypersensitivity reactions, because

a. massive histamine release from mast cells leads to vasodilation.
b. anaphylaxis results in large volume losses secondary to sweating.
c. toxins released into the blood interfere with cardiac function.
d. hypoxia resulting from bronchoconstriction impairs cardiac function.

Answer 1

a. massive histamine release from mast cells leads to vasodilation.

Step-by-step explanation:

Type I hypersensitivity caused by massive histamine release may be directly linked to hypotension. Histamine is a potent pharmacological mediator with vascular and smooth muscle action, which causes vasodilation, bronchoconstriction, smooth muscle contraction and edema. When histamine is released in large quantities it can lead to vasodilation and trigger a severe hypersensitivity reaction.

One of the causes of hypotension is unbridled histamine release, so type I hypersensitivity and hypotension may be related.