Distributive Shock

 Distributive Shock 💥💥💥💥

Etiology (Causes)

Type	Common Causes
Septic Shock	Infection (especially gram-negative bacteremia), dysregulated host response to infection
Anaphylactic Shock	Drug reactions (e.g., sulfa, contrast), insect stings, food allergies (e.g., peanuts)
Neurogenic Shock	Spinal cord injury, traumatic brain injury, cerebral hemorrhage, neuraxial anesthesia, acute adrenal insufficiency, abrupt glucocorticoid withdrawal

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Pathophysiology

• Common Mechanism: Vasodilation ± capillary leak → redistribution of intravascular fluid to extravascular space → hypotension → tissue hypoperfusion

Specific Mechanisms by Type:

1. Septic Shock

   • Dysregulated immune response → systemic vasodilation & capillary leakage

   • Cytokines → myocardial depression

   • Effect on CO:

     • Early: ↑ HR & contractility → hyperdynamic (“warm”) shock

     • Late: ↓ preload & myocardial depression → hypodynamic (“cold”) shock

2. Neurogenic Shock

   • Damage to autonomic pathways → loss of sympathetic tone → unopposed vagal tone → vasodilation & blood pooling

   • Effect on CO: ↓ HR (bradycardia), ↓ contractility; can persist days–weeks post-SCI

   • ↓ catecholamines → absent compensatory ↑ HR & contractility

3. Anaphylactic Shock

   • IgE-mediated (type I) or non-IgE → mast cell degranulation → histamine release → systemic vasodilation & capillary leakage

   • Effect on CO:

     • Early: ↑ HR & stroke volume → ↑ CO

     • Late: ↓ vascular tone & ↑ capillary permeability → ↓ venous return → ↓ CO → ↓ coronary perfusion → ↓ contractility

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Management – Key Components

1. Volume Expansion: Fluid resuscitation (careful monitoring for overload in specific patients)

2. Vasopressors: To reverse vasodilation (norepinephrine preferred)

3. Treat Underlying Cause:

   • Septic: antibiotics, source control

   • Anaphylactic: epinephrine, remove allergen

   • Neurogenic: spinal decompression if indicated, glucocorticoid replacement if adrenal insufficiency

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Key Takeaways:

• Distributive shock = vessel problem, not pump problem

• CO may be high initially (warm shock) or low later (cold shock)

• Early recognition & rapid reversal of vasodilation + supportive care are crucial

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 THANK YOU❤💖