Involvement of the central nervous system in radiation-induced multi-organ dysfunction and/or failure

Abstract

The presence of multiple organ dysfunction syndrome (MODS) in victims of the recent accidents in Nesvizh and Tokai-mura suggests that radiation-induced systemic inflammatory response syndrome (SIRS) occurs in acute radiation sickness (ARS). Multiple organ failure (MOF) refers to the gradual and sequential failure of organs occurring after a wide spectrum of insults. MOF is believed to be the consequence of the host's response to the insult and is strongly linked to SIRS. It is believed that SIRS is mediated by endogenous regulators that are released during the acute phase reaction. The resulting interplay of cytokines may compromise homeostasis of various organ systems, resulting in MODS. In the classical description of ARS, the role of the central nervous system (CNS) has been underestimated. Today, it is recognised that the CNS is a radiosensitive organ whose degree of dysfunction can be quantified by electrophysiological, biochemical and/or behavioural parameters. Abnormalities in CNS function defined by these parameters may occur at a low dose of whole body radiation. The evolving concept of radiation-induced MODS in ARS provides a framework for evaluating injury to the CNS. Ionising radiation also induces an inflammatory response that may be specific to the CNS. This response is observed after either local irradiation of the CNS or whole body irradiation. The relationship between inflammatory responses in the CNS and the peripheral nervous system is undefined. Whether or not the CNS inflammatory response syndrome is a consequence of SIRS or is an independent syndrome remains an open question. The answer to this question may have implications regarding therapy and medical management of irradiated victims.