Which of the following statements regarding anaphylaxis is correct?
A. Patients with asthma are at lower risk of developing anaphylaxis.
B. Anaphylaxis is characterized by airway swelling and hypotension.
C. Most anaphylactic reactions occur within 60 minutes after exposure.
D. The signs of anaphylaxis are caused by widespread vasoconstriction.
The Correct Answer and Explanation is :
The correct answer is B. Anaphylaxis is characterized by airway swelling and hypotension.
Explanation:
Anaphylaxis is a severe, life-threatening allergic reaction that occurs rapidly after exposure to an allergen. It is a systemic response involving multiple organ systems, often leading to critical symptoms that can escalate quickly.
Airway Swelling and Hypotension (Option B): One of the hallmark signs of anaphylaxis is the swelling of the airway, which can lead to difficulty breathing and potentially suffocation. This occurs due to the release of mediators such as histamines and leukotrienes, which cause blood vessels to dilate (vasodilation) and increase permeability, leading to edema. Hypotension, or low blood pressure, is also a significant feature of anaphylaxis. The widespread vasodilation and fluid leakage from blood vessels result in a decrease in blood volume, causing a drop in blood pressure that can be life-threatening.
Asthma and Anaphylaxis Risk (Option A): Contrary to this statement, patients with asthma are actually at a higher risk of experiencing anaphylaxis. The airway hyperreactivity seen in asthma can complicate anaphylactic reactions, making it more difficult to manage respiratory distress.
Timing of Reactions (Option C): While it is true that many anaphylactic reactions occur within minutes, it’s important to note that they can happen within seconds to hours after exposure. Therefore, while most reactions occur quickly, the statement is misleading regarding the precise time frame.
Vasoconstriction (Option D): The signs of anaphylaxis are primarily due to vasodilation, not vasoconstriction. The release of mediators during an allergic reaction causes blood vessels to widen, leading to decreased blood pressure and potential shock.
In summary, option B accurately describes key features of anaphylaxis, highlighting the critical need for prompt recognition and treatment, typically with epinephrine.