Sepsis

Sepsis from an infectious etiology is a major cause of morbidity and mortality in the United States. Despite recent advances in neonatal and pediatric critical care medicine, the number of children suffering from sepsis continues to rise. A review in the New England Journal of Medicine reported an 8.7% annual increase in the incidence of sepsis in the United States. A national survey of nearly 1.6 million hospitalized children, ages 19 years or younger, revealed 42,364 cases of sepsis per year. Infants were affected more often than older children.

Sepsis can be caused by a variety of insults, including infection or tissue injury. Invasive microbial infections often result from the inability of the intrinsic host defense mechanisms to combat certain virulence factors. The most frequent organisms identifi ed in the pediatric and adult populations include Escherichia coli, Pseudomonas aeruginosa, Klebsiella, and Bacteri-odes species. The most common pathogens in the neonatal population are group B streptococci and E. coli. These pathogens induce a localized infl ammatory response in the host designed to destroy the microorganisms. Lack of control, over-exuberance of this infl ammatory response, or inability of the host to eradicate the infection may lead to a clinical syndrome characterized by fever, inadequate tissue perfusion, organ dysfunction, and generalized edema. This constellation of symptoms is referred to as the sepsis syndrome or the systemic infl ammatory response syndrome (SIRS). This may represent the fi nal common pathway through which microbial infection or extensive tissue injury results in the demise of the host.