A large accumulation of blood in the pericardial sac would cause which type of shock?

• A. Cardiogenic
• B. Hypovolemic
• C. Obstructive
• D. Neurogenic

Answer: (C)

Obstructive shock occurs when something physically blocks or restricts the heart’s ability to circulate blood. A large amount of blood in the pericardial sac (cardiac tamponade) externally compresses the heart, preventing it from filling properly during diastole. With the ventricles unable to fill, preload and ultimately stroke volume fall, so cardiac output drops and tissues don't get enough blood. That blockage at the level of filling defines this as obstructive shock, even though the heart muscle itself may be fine.

This differs from other types: cardiogenic shock comes from the heart failing to pump effectively, hypovolemic shock from too little circulating blood volume, and neurogenic shock from widespread vasodilation due to loss of sympathetic tone.