Case report: Long-term cognitive sequelae of sarin exposure

Abstract

The long-term sequelae of acute sarin exposure are not well understood. The largest clinical cohort resulted from the 1994 and 1995 attacks in Japan. Observers noted mostly psychiatric sequelae, with a high prevalence of post-traumatic stress disorder (PTSD). We describe neurocognitive findings that may represent sequelae of low-level sarin exposure in Iraq.

Introduction

Nerve agent exposure has garnered public attention in the recent decade. Sarin, an organophosphate acetylcholinesterase inhibitor, first became a household term after the Tokyo subway bombing by Aum Shinriyko in 1995. Since then, the world has seen a rash of chemical and biological terrorist activity to include the anthrax release into the US postal system. A result is the increasing awareness of the potential for smaller organizations to turn to chemical and biological agents as their weapon of choice. These are cheap, can be delivered in mass quantities and may have the added psychological impact of contagious or delayed effects.

The US invasion of Iraq was driven partly by the fear of such effects and consequently the decision to deter a suspected nuclear, biological, and chemical threat. Although US forces never found production or storage facilities, the first cases of exposure with weaponized sarin emerged in the summer of 2004. The insurgency made public news with these first chemical casualties when two soldiers were exposed to sarin gas by means of an improvised explosive device (IED).

The long-term neurologic sequelae of sarin exposure remain unclear. What little literature exists comes almost entirely from the Japanese healthcare system's experience with the casualties and healthcare workers of the Tokyo subway bombing. The majority of this body of literature encompasses only the psychiatric sequelae, given the high prevalence of post-traumatic stress disorder. We describe the neurocognitive sequelae of one of the two incipient cases of exposure in Iraq, which is, to our knowledge, the first description of sarin exposure since 1995 and the first ever report of a sarin combat casualty.