Which type of shock is caused by widespread vasodilation leading to a relative reduction in intravascular volume?

• A. Cardiogenic Shock
• B. Hypovolemic Shock
• C. Distributive Shock
• D. Burn Shock

Answer: (C)

Distributive shock is defined by widespread vasodilation that lowers the resistance of the blood vessels, causing blood to pool in the peripheral circulation. This creates a relative intravascular volume deficit—there may be plenty of total blood, but not enough in the central vessels to return to the heart and perfuse tissues. The result is inadequate tissue perfusion despite an apparently normal or even adequate overall volume. This category includes conditions like septic, anaphylactic, and neurogenic shock, where the problem is the failure to maintain vascular tone.

In contrast, cardiogenic shock comes from the heart’s inability to pump effectively, so there’s poor forward flow due to pump failure rather than redistribution of volume. Hypovolemic shock is due to actual loss of intravascular fluid, such as from hemorrhage or severe dehydration, leading to reduced preload. Burn shock involves significant fluid shifting and loss from the vascular space after a major burn, which is a form of hypovolemia rather than primary vasodilation.