(3) Nerve agent poisoning is easily identified by the characteristic signs and symptoms as follows:
(_a_) =MILD= symptoms (self-aid). Casualties with MILD symptoms may experience most or all of the following:
· Difficulty in seeing (dimness of vision) (miosis).
· Tightness in the chest or difficulty in breathing.
· Localized sweating and muscular twitching in the contaminated area.
(_b_) Casualties with =MODERATE= symptoms (buddy aid) will experience an increase in the severity of most or all of the MILD symptoms. Especially prominent will be an increase in fatigue, weakness, and muscle fasciculations. The progress of symptoms from MILD to MODERATE indicates either inadequate atropine treatment or continuing exposure to agent.
(_c_) =SEVERE= symptoms (buddy aid). Casualties with SEVERE symptoms may experience most or all of the MILD symptoms, plus most or all of the following:
· Wheezing, dyspnea (severe difficulty in breathing), and coughing.
· Severe muscular twitching and general weakness.
_b._ There are three major families of blister agents (vesicants); HD and HN, L, and CX. Most vesicants (except CX) are relatively persistent. Mustards can modify the structure of nucleic acids, cellular membranes, and proteins by combining with certain functional groups (particularly the sulfhydryl-containing enzymes) for which they have an affinity.
(1) The cutaneous syndrome is divided into four phases: latent, erythema, vesication, and necrosis. Vesicants can penetrate the skin by contact with either liquid or vapor. The latent period is characteristic of the agent. For mustards it is usually several hours, for L it is short, and for CX it is negligible. The latent period is also affected by the dose, temperature, and humidity. The symptoms of the erythema phase are red, painful itching followed by painful necrosis that heals slowly.
(2) In the eyes, vesicants produce intense pain and photophobia. Blistering of the eyelids and mucous membranes can result in temporary blindness. Even after recovery, scars on the cornea can reduce visual acuity.
(3) In the respiratory tract, these agents attack the mucous membranes irritating them. They can paralyze vocal chords and can lead to chemical pneumonitis, or possibly death.