Clinical and Laboratory Diagnosis of Chemical Warfare Agent Exposure
Highly toxic organophosphorus based nerve agents were developed by different countries for use as chemical warfare agents and have been repeatedly used during military conflicts, against civilian populations and by terrorists. The last massive attack with the nerve agent sarin occurred in 2013 in Syria. Exposure to nerve agents can result in life threatening toxic effects and requires rapid diagnosis and treatment. Typical signs of poisoning enable clinical diagnosis in cases of nerve agent exposure with rapid onset of toxic signs; however, these may be delayed in scenarios with low level and percutaneous exposure to nerve agents. This demands the development and availability of laboratory tools for supporting the clinical diagnosis of nerve agent exposure and to provide decisive information for the initiation and optimization of specific antidotal treatment. At present, the determination of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is the only feasible laboratory tool for the confirmation of a clinical diagnosis of nerve agent exposure and an invaluable tool for the pre-symptomatic diagnosis of percutaneous exposure. The determination of cholinesterase status is an easy to use tool for therapeutic monitoring in nerve agent poisoning and can give essential information on the duration of oxime administration. In the meantime, ready to use kits for the onsite diagnostic determination of AChE and BChE activities in human blood and for bedside therapeutic monitoring utilizing cholinesterase status have been developed and implemented. This chapter provides an overview on recent findings and developments in the field of clinical and laboratory diagnosis of chemical warfare nerve agents.