Infection continues to be a leading cause of intensive care unit death. The host response to infection can be seen as a pattern recognition receptor (PRR)-mediated dysregulation of the immune system following pathogen invasion in which a careful balance between inflammatory and anti-inflammatory responses is vital. A measured and rapid response to microbial invasion is essential to health. The same immunological and coagulation systems that protect against localized infection can act to our disadvantage when these systems are activated systemically during generalized microbial infection. Toll-like receptors (TLR), the inflammasomes and other PRRs initiate the host response after recognition of pathogen-associated-molecular-patterns (PAMPs) or endogenous danger-associated-molecular-patterns (DAMPs). The systemic host response to infection will result in activation of coagulation, downregulation of physiological anticoagulant mechanisms, and inhibition of fibrinolysis. Further dissection of the role of host–pathogen interactions, the cytokine response, the coagulation cascade and their multidirectional interactions in sepsis should lead towards the development of new therapeutic approaches in the critically ill who are faced with infection.
