What is the most common cause of shock?

The most common cause of shock is gram-negative sepsis, primarily due to the widespread occurrence of infections that lead to systemic inflammatory response syndrome (SIRS). When gram-negative bacteria enter the bloodstream, they can trigger a severe response from the immune system, resulting in vasodilation, increased vascular permeability, and ultimately a reduction in systemic vascular resistance. This cascade of events leads to hypotension and inadequate tissue perfusion, hallmark signs of shock.

In the context of clinical practice, gram-negative sepsis is particularly significant because it can lead to septic shock, which has a high mortality rate if not recognized and treated promptly. The prevalence of gram-negative bacteria in hospital-acquired infections, combined with the fact that sepsis can quickly escalate, makes it a critical consideration in emergency medicine and critical care.

Other causes of shock, such as cardiogenic shock, hemorrhagic shock, and neurogenic shock, are also vital to recognize but are less common overall. Cardiogenic shock is typically a result of severe heart failure, hemorrhagic shock arises from significant blood loss, and neurogenic shock usually follows spinal cord injury. While these conditions are important causes of shock, gram-negative sepsis represents a more frequently encountered etiology, particularly in hospital settings.