Which of the following is a distributive (vasodilatory) shock type?

• A. Hypovolemic shock
• B. Cardiogenic shock
• C. Obstructive shock
• D. Septic shock

Answer: (D)

Distributive shock is defined by widespread vasodilation and maldistribution of circulating blood, so the total blood volume may be present but the vessels are dilated enough that tissues get insufficient perfusion. Septic shock fits this pattern because infection triggers a systemic inflammatory response that releases mediators like cytokines and nitric oxide, causing relaxation of arterioles and venules and increased capillary permeability. The result is a drop in systemic vascular resistance and relative hypovolemia, with the heart often trying to compensate by increasing output. Early in septic shock you can see warm, flushed skin and a rapid pulse as perfusion is maintained despite low resistance; as it worsens, perfusion declines and the patient can become cold and hypotensive. This behavior distinguishes septic shock from hypovolemic shock (true loss of blood volume), cardiogenic shock (pump failure), and obstructive shock (physical obstruction to blood flow).