Which of the following is primarily caused by blood or fluid loss?

• A. Hypovolemic Shock
• B. Septic Shock
• C. Neurogenic Shock
• D. Anaphylactic Shock

Answer: (A)

The tendency of this question is to test how shock types differ by what causes the drop in tissue perfusion. Hypovolemic shock happens when intravascular volume falls because of blood loss or severe fluid loss (think hemorrhage, dehydration, burns with plasma loss). With less circulating blood, venous return to the heart drops, preload falls, and stroke volume and cardiac output decline, leading to low blood pressure and poor tissue perfusion. The body tries to compensate with a faster heart rate and vasoconstriction to maintain pressure, but ongoing volume loss can overwhelm these mechanisms and progress to organ dysfunction. The other shocks involve different primary mechanisms: septic shock is driven by infection causing widespread vasodilation and capillary leak; neurogenic shock results from loss of sympathetic tone causing vasodilation; anaphylactic shock from an allergic reaction causes vasodilation and increased permeability. Because this question asks which is primarily caused by blood or fluid loss, hypovolemic shock best fits that mechanism.