If a patient undergoing emergency surgery with known histamine intolerance suddenly experiences severe hypotension despite fluid resuscitation, which mechanism explains this physiological crash?

💡 Explanation

Widespread vasodilation causes profound hypotension during histamine intolerance because mast cell degranulation releases excessive histamine, leading to systemic vasodilation and vascular permeability. Therefore, mast cell degranulation explains the effect, rather than baroreceptor failure which would normally compensate for hypotension.

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