Pathophysiology of Sepsis

Sepsis is a condition of life-threatening organ dysfunction caused by a dysregulated host response to infection. It is the result of a series of exaggerated physiologic responses that lead to simultaneous hyper- and hypoinflammatory states. In the hyperinflammatory phase, there is an exuberant release of cytokines, commonly referred to as a cytokine storm. The immune-suppressive phase is characterized by counterregulatory attempts to achieve homeostasis that sometimes "overshoot", leaving the host in a state of immunosuppression, thus predisposing to recurrent nosocomial and secondary infections. The aging population with comorbidities faces higher risks of immune dysfunction and inflammation. Thus, the number of sepsis survivors that develop subsequent infections is predicted to rise substantially in the next few decades. Understanding sepsis-induced immune dysregulation may enhance surveillance and outcomes. This review is intended to describe the pathophysiology of sepsis and its effects on the immune system.