What is the primary chemical mediator involved in the inflammatory response and pain generation following a spilled hot water burn?

Chemical Mediator in Hot Water Burns

The primary chemical mediator involved in the inflammatory response and pain generation following a spilled hot water burn is prostaglandins (option D). Prostaglandins play a crucial role in the inflammatory cascade after thermal injuries by acting as vasodilators that potentiate plasma exudation and contribute significantly to the pain response 1.

Mechanism of Inflammatory Response in Thermal Burns

When hot water contacts skin, the following inflammatory cascade occurs:

1. Initial tissue damage triggers the release of inflammatory mediators
2. Prostaglandins are produced from arachidonic acid metabolism and serve as key vasodilators 1, 2
3. These prostaglandins work in conjunction with other mediators to produce the cardinal signs of inflammation:
   • Redness (rubor)
   • Heat (calor)
   • Swelling (tumor)
   • Pain (dolor)

Role of Different Mediators

While multiple mediators are involved in the burn response, their roles differ:

• Prostaglandins (D): Primary vasodilators that potentiate plasma exudation and mediate pain 1
• Bradykinins (B): Act as permeability-increasing mediators but are not the primary chemical mediator 1
• Substance P: Released from injured nerves and supports neurogenic mediation of inflammation and vasodilation in early wound repair 3
• Histamine: Released from mast cells and contributes to vascular permeability 3
• Thromboxane (C): An arachidonic acid metabolite involved in platelet aggregation but not the primary mediator in thermal burns 2
• Serotonin (A): Not identified as a primary mediator in the burn response in the provided evidence

Clinical Implications

Understanding prostaglandins as the primary mediator explains why:

• NSAIDs are effective in burn pain management as they inhibit prostaglandin synthesis 4
• A multimodal approach to pain management including acetaminophen and NSAIDs is recommended for burn injuries 4

Pain Management Based on This Understanding

The American Society of Anesthesiologists recommends a multimodal approach to pain management in burns that includes:

• Acetaminophen
• NSAIDs (which specifically target prostaglandin synthesis)
• Opioids as needed for more severe pain 4

Important Considerations

• The inflammatory response to burns involves complex interactions between multiple mediators, not just a single chemical 1, 2
• The model of inflammation involves the interaction between permeability-increasing mediators (like bradykinin) and vasodilators (prostaglandins) 1
• Non-steroidal anti-inflammatory drugs work by inhibiting prostaglandin synthesis, thus reducing vasodilation and inflammatory swelling 1

In conclusion, while multiple mediators participate in the burn response, prostaglandins serve as the primary chemical mediator in the inflammatory and pain response following a hot water burn.