Agent 15 Poisoning Clinical Presentation

Updated: Apr 10, 2015
  • Author: Geoffrey M Fitzgerald, MD; Chief Editor: Duane C Caneva, MD, MSc  more...
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Presentation

History

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  • The patient may complain of dry mouth, a hot feeling, or blurred vision.

  • Changes in mental status produced by incapacitating agents may leave some patients delirious to the point that they fail to or are unable to report symptoms.

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Physical

Remarkably little variation exists among individuals when anticholinergics are administered.

  • Following exposure, typically a latent period of 30 minutes to 24 hours occurs before signs and symptoms appear.

  • Anticholinergic toxicity caused by BZ or Agent 15 can last up to 3-4 days, depending on the amount of drug absorbed.

  • Peripheral effects usually precede CNS effects and can be summarized by the mnemonic "dry as a bone, hot as Hades, red as a beet, and blind as a bat."

    • "Dry as a bone" results from decreased glandular secretions in the oral pharynx, GI tract, and eccrine and apocrine glands. Urinary retention also is common.

    • "Hot as Hades" refers to hyperthermia caused by decreased sweating.

    • The body attempts to maintain thermoregulation via compensatory cutaneous vasodilatation, hence "red as a beet."

    • Decreased cholinergic stimulation of the pupillary sphincter muscle causes mydriasis. Anticholinergic effects on the ciliary muscles inhibit accommodation, hence "blind as a bat."

    • Anticholinergic effects on the heart produce tachycardia. This occasionally is preceded by a bradycardia that results from anticholinergic effects in the brain stem.

  • The CNS effects of BZ and Agent 15 make them effective incapacitants.

    • Patients receiving these agents react with mental status changes ("mad as a hatter") in a dose-dependent fashion.

    • After a latent period and following the appearance of the peripheral effects, the casualty's mental status begins to fluctuate between a relatively conscious state and frank delirium.

    • Level of consciousness can range from drowsiness to coma.

    • Disorientation to time and place, decreased social restraint with inappropriate behavior, and decreased short-term memory are common.

    • Speech becomes slurred and indistinct.

    • Poor coordination leads to ataxia and agraphia.

    • Anticholinergic toxicity can produce vivid and realistic hallucinations that tend to decrease in size over time. For example, a polar bear may be replaced by a smaller animal such as a rabbit as the toxidrome clears.

    • When multiple victims of anticholinergic toxicity interact, they may play off each other's delirium. An example is 2 victims playing tennis with imaginary racquets. Another term for this shared hallucination is "folie a deux."

    • Phantom behaviors such as plucking or picking at one's clothes (ie, wool gathering) often were observed in Army test subjects who received BZ.

    • As the BZ victim's delirium clears, paranoid tendencies are not uncommon.

  • Of final note on the examination is an increase in deep tendon reflexes. Anticholinergic effects on the Renshaw interneurons in the spinal cord cause hyperreflexia.

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Causes

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  • Consider any cause of delirium. Psychiatric disorders such as anxiety reaction also are in the differential diagnosis.

  • The presence of peripheral anticholinergic signs suggests another source of anticholinergic such as scopolamine, [1] atropine, jimsonweed, or other anticholinergic source exposure.

  • Usually, 6-7 MARK-1 Autoinjectors (ie, 12-14 mg of IM atropine) are needed to cause a significant degree of confusion.

  • Nerve agent poisoning can be differentiated by its hyperstimulation of glands.

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