True about anaphylactic shock
**Core Concept**
Anaphylactic shock is a severe, life-threatening allergic reaction that occurs within minutes of exposure to an allergen. It is characterized by a rapid onset of symptoms, including hypotension, tachycardia, bronchospasm, and cutaneous flushing, resulting from the release of histamine and other mediators from mast cells.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of anaphylactic shock. Anaphylaxis is triggered by the cross-linking of IgE antibodies on mast cells, leading to the release of histamine and other preformed mediators, such as bradykinin, serotonin, and leukotrienes. These mediators cause vasodilation, increased vascular permeability, and smooth muscle contraction, resulting in the characteristic symptoms of anaphylaxis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because anaphylactic shock is not caused by an increase in circulating catecholamines, but rather by the release of histamine and other mediators from mast cells.
**Option B:** This option is incorrect because the symptoms of anaphylaxis typically begin within minutes, not hours, after exposure to the allergen.
**Option C:** This option is incorrect because while mast cell stabilization is a treatment for anaphylaxis, it is not a defining characteristic of the condition.
**Clinical Pearl / High-Yield Fact**
A key feature of anaphylaxis is the rapid onset of symptoms, which can occur within seconds to minutes after exposure to the allergen. This is why prompt recognition and treatment are critical in preventing serious complications.
**Correct Answer:**