Anaphylactic shock, characterized by a severe, systemic allergic reaction leading to massive vasodilation and increased capillary permeability, is classified as which type of shock?

1. A

   Cardiogenic Shock

2. B

   Hypovolemic Shock

3. C

   Distributive Shock

4. D

   Obstructive Shock

Appeared in: NORCET 9 Prelims-2025

Explanation

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• Anaphylactic shock is classified as a type of distributive shock.
• The core pathophysiology involves massive vasodilation and increased capillary permeability, triggered by a systemic allergic reaction.
• This leads to a maldistribution of blood volume (relative hypovolemia), where blood pools in the periphery instead of circulating effectively, causing a sharp drop in blood pressure.
• Other common causes of distributive shock include sepsis and neurogenic injury.

Why Other Options Were Wrong

• Option A: Cardiogenic shock results from primary heart (pump) failure, where the heart cannot effectively pump blood. Anaphylaxis is a problem of the blood vessels (pipes), not the heart itself.
• Option B: Hypovolemic shock is caused by an absolute loss of blood or fluid volume from the body, such as in a hemorrhage or severe dehydration. In anaphylaxis, the fluid volume is still within the body but has shifted out of the blood vessels.
• Option D: Obstructive shock is caused by a physical blockage that impedes blood flow to or from the heart. Anaphylaxis does not involve a physical obstruction.

Related Visual

• Visual 1: Flowchart - Illustrating the progression from allergen exposure to histamine release, vasodilation, capillary leak, and finally, distributive shock.
• Visual 2: Diagram - A comparative diagram showing the four types of shock, using simple icons for the heart (pump), blood volume (volume), blood vessels (pipes), and a blockage (obstruction) to clarify the primary defect in each type.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of shock based on pathophysiology as background academic context rather than a clinical decision trigger.
• Rapidly identifying the type of shock is critical for nurses, as treatments are vastly different. Misidentifying the shock type can be fatal.
• The priority for anaphylactic shock is administering epinephrine, which constricts blood vessels and opens airways, directly counteracting the pathophysiology. This is followed by fluid resuscitation and antihistamines.
• What if? If a patient experiencing anaphylaxis is also taking a beta-blocker medication, their response to epinephrine may be blunted. In this case, glucagon may be administered as it can increase heart rate and contractility through a different cellular pathway.

How to Approach the Question

• First, identify the core concept of the question, which is the classification of anaphylactic shock.
• Focus on the key pathophysiological descriptions provided in the stem: 'massive vasodilation' and 'increased capillary permeability'.
• Recall the four primary categories of shock and their fundamental causes: Cardiogenic (pump failure), Hypovolemic (volume loss), Distributive (vessel/pipe problem), and Obstructive (blockage).
• Connect the keyword 'vasodilation' (a problem with the blood vessels or 'pipes') directly to the definition of Distributive shock.
• Systematically eliminate the other options because their underlying causes (pump failure, volume loss, or blockage) do not match the description of anaphylaxis.
• Select 'Distributive Shock' as it is the only category defined by widespread vasodilation and maldistribution of blood flow.

Concept Tested & Keywords

• Concept Tested: Classification of shock based on pathophysiology.
• Stem keywords: Anaphylactic shock, systemic allergic reaction, massive vasodilation, increased capillary permeability, type of shock
• Lead-in keywords: classified as

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