Fourth Generation Agents

Differential Diagnosis

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Differential Diagnosis

Key Clinical Distinguishing Features of FGAs versus other Nerve Agents

  • FGAs are low volatility nerve agents, like VX, and therefore most likely to be encountered as a liquid.
  • In general, the latent period between dermal exposure and symptom onset may be longer for FGAs than for VX and can be up to 3 days. Inhalational, ingestion, or large dermal exposures will have shorter latent periods.
  • FGAs are persistent; if not decontaminated, they can remain on environmental surfaces for days or even many months. Physical surfaces must be decontaminated to prevent additional exposures.
  • Decontamination of skin and hair is crucial and may provide clinical benefit even when performed hours to days after exposure to liquid agent, although the earlier the decontamination, the better.
  • Bronchoconstriction has been a prominent feature of FGA toxicity in animal studies but has not been observed in the very limited number of human cases. If it occurs, bronchoconstriction may be difficult to manage clinically.
  • Seizure activity has been a prominent feature of FGA toxicity in animal studies but has not been observed in the very limited number of human cases.
  • FGAs may cause severe metabolic acidosis with markedly elevated serum lactate.
  • Patients poisoned by FGAs may need medication and intensive supportive care over an extended duration. Multiple casualties may strain local resources at the point of care.
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed