Which condition is classified as obstructive shock?

• A. Pericardial tamponade
• B. Septic shock
• C. Cardiogenic shock
• D. Hypovolemic shock

Answer: (A)

Obstructive shock happens when a physical blockage prevents the heart from filling or pumping effectively, so the body doesn’t get enough blood even though the heart may be otherwise healthy. Pericardial tamponade fits this idea: fluid accumulates in the pericardial sac and, as pressure rises, the heart is squeezed during diastole. This limits venous return and reduces filling of the chambers, which lowers stroke volume and cardiac output, leading to shock.

This is different from the other conditions. Septic shock is a distributive form caused by widespread vasodilation and increased capillary permeability, not a mechanical blockage. Cardiogenic shock results from the heart’s own pumping failure, often from a damaged or failing myocardium, but without an external obstruction to filling. Hypovolemic shock comes from a significant loss of circulating blood volume, reducing preload rather than creating a physical blockade to filling.

So the condition that classically causes obstructive shock is pericardial tamponade, because the obstruction is external to the heart and directly impedes its ability to fill.