Chemical Mediator in Spilled Hot Water Burns
Histamine is the primary chemical mediator in a scald burn, triggering the immediate inflammatory cascade after hot water exposure. 1
Pathophysiology of Scald Burns
The inflammatory response in thermal injuries follows a specific sequence:
Initial phase: Histamine is released as the earliest chemical mediator following thermal injury 1, 2
- Causes immediate vasodilation and increased microvascular permeability
- Triggers the initial inflammatory cascade
Secondary mediators: Following histamine release, other mediators are activated in sequence 1, 3:
- Bradykinins
- Prostaglandins
- Thromboxanes
- Leukotrienes
Mechanism of Action
Histamine's role in scald burns involves:
- Direct activation of vascular endothelium causing increased permeability 2
- Creation of endothelial gaps allowing fluid shift into interstitial spaces
- Triggering of the earliest stage of vasodilation 2
The inflammatory cascade progresses with a "two-hit" model rather than a simple linear pathway:
- Histamine acts as the vascular permeability-increasing mediator
- Prostaglandins subsequently act as vasodilators that potentiate plasma exudation 4
Clinical Implications
Understanding histamine as the primary mediator has important treatment implications:
- Immediate cooling of burns helps limit the histamine-mediated inflammatory response 1
- Fluid management is critical as histamine-triggered increases in vascular permeability lead to significant fluid shifts 1, 3
- Pain management requires multimodal approaches as the histamine-initiated cascade contributes significantly to burn pain 1
Common Pitfalls
- Misattribution: While prostaglandins, thromboxanes, and bradykinins are important in burn pathophysiology, they are not the initial mediators 1, 2
- Oversimplification: The inflammatory response is complex and involves multiple mediators working in sequence and synergistically 4
- Treatment delay: Failure to recognize histamine's early role may delay appropriate cooling interventions that could limit the inflammatory cascade 1
Therefore, among the options provided (Serotonin, Bradykinins, Thromboxane, Prostaglandins), none represent the primary chemical mediator in a spilled hot water burn. The correct answer would be Histamine.