Hypovolemic shock is primarily caused by which of the following?

• A. Loss of a large amount of blood or fluid
• B. Heart rhythm disturbances
• C. Infection and toxins in the bloodstream
• D. Allergic reaction

Answer: (A)

Hypovolemic shock occurs when there isn’t enough circulating blood volume to properly fill the vascular system, so the heart can’t maintain adequate pressure and tissue perfusion. This happens most often after losing a large amount of blood or fluids, such as from hemorrhage, severe dehydration, burns, or ongoing fluid losses. With the reduced volume, venous return to the heart drops, stroke volume and cardiac output decrease, and blood pressure falls. The body may try to compensate with faster heart rate and vasoconstriction, but organ perfusion remains compromised.

Other scenarios involve different mechanisms: heart rhythm disturbances can reduce the heart’s pumping efficiency but are not the primary cause of hypovolemia. Infection and toxins in the bloodstream lead to septic shock, characterized by systemic vasodilation and increased capillary permeability. An allergic reaction can cause anaphylactic shock, also involving vasodilation and fluid leakage.