Page 112 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Chemicals of Terrorism Chapter | 5 79

VetBooks.ir does not prevent permanent damage (Goldfrank et al., low-melting point crystalline solid, readily soluble in
water. The solid form can produce enough vapor to cause
1998).
Animals should be rinsed with copious amounts of
symptoms. Phosgene oxime has an unpleasant, peppery
water. A 5% solution of sodium hypochlorite (diluted liq- and irritating odor. Phosgene oxime is not a true vesicant
uid household bleach) should be used as soon as possible as it does not cause skin blisters but it does have a rapid
on contaminated skin. Topical application of a 5% BAL dermal urticant and corrosive effect. It can be dispersed
ointment within 15 min of an exposure has been reported as a liquid or vapor causing almost immediate tissue dam-
to be effective in diminishing the blistering effects of age upon contact.
Lewisite (Smith, 1999). Wash BAL ointment off after
5 min. The ointment may cause stinging, itching or urti- Pharmacokinetics/Toxicokinetics
caria. Burns should be managed as discussed previously
under mustard gas. Pain control is very important. Absorption in both dermal and inhalational exposures is
Chelation is indicated if there is coughing, dyspnea, complete and rapid (within seconds) (Sidell et al., 1997).
pulmonary edema, or skin burns larger than palm size Dermal lesions form within seconds. Phosgene oxime will
(Goldfrank et al., 1998). BAL is an effective arsenic che- dissolve in sweat and move to other nonexposed areas of
lator, but requires painful deep intramuscular injections the body as it is soluble in water (DeRosa et al., 2002).
and has numerous side effects (hypertension, tachycardia, Pulmonary edema can be evident on thoracic radiographs
vomiting, lacrimation, sweating). BAL will increase the within 2 h of high-dose exposure, 4 6 h of moderate
clearance rate of arsenic, but it is contraindicated in ani- exposure, and approximately 8 24 h after low-dose expo-
mals with liver damage. 2,3-Dimercaptosuccinic acid sure (Sidell et al., 1997).
(DMSA, Succimer) appears to be a very effective arsenic
chelator in animals (Graziano et al., 1978). DMSA is an Mechanism of Action
oral agent and is relatively nontoxic. It may be used fol-
lowing BAL. 2,3-Dimercapto-1-propanesulfonic acid is The exact mechanism action is unknown, but it has been
related to DMSA and is used for heavy metal poisoning, proposed that phosgene oxime reacts with SH and NH 2
especially in Europe. It has been effective in protecting groups and activates mast cells (Sidell et al., 1997;
rabbits from the lethal effects of Lewisite (Aposhian Tewari-Singh et al., 2017). Phosgene oxime exerts its
et al., 1982). greatest effects in the first capillary bed it encounters.

Concluding Remarks Toxicity
Lewisite can remain in the environment for about 1 day. Both liquid and vaporous phosgene oxime cause intense,
It reacts with water to yield a solid arsenoxide that also immediate pain and local tissue destruction on contact with
has vesicant properties. When in contact with strong skin, eyes and mucous membranes (Sidell et al., 1997).
alkalis, Lewisite is decomposed to less harmful sub- Damage to the eyes, skin and airways is similar to that
stances. The potential for secondary contamination is high caused by mustard gas. Following dermal contact with
and material spilled on clothing may be transferred to either the liquid or vapor, grayish tissue damage may be
rescuers or medical personnel. Lewisite is considered a seen within several minutes. The damaged areas are
terrorist threat, as it is easy to produce and has a quick erythematous and extremely painful. Within 1 h, the area
onset of signs. Carcasses should be buried deeply (away becomes edematous. Browning of the skin and blistering
from water supplies), rendered or incinerated to insure occurs the next day. In about 3 weeks, desquamation,
safety of the food supply. necrosis, crust formation, and purulent exudate occur.
Pain can last for several days. Skin irritation begins
3
at 0.2 mg/min/m (12 s) for humans and is intolerable
PHOSGENE OXIME 3mg/min/m (1 min) (USACHPPM, 2001d).
3
Phosgene oxime is very irritating to the eyes. Very
Background
low concentrations can cause lacrimation, inflammation,
Phosgene oxime (Agent CX, “Nettle Rush,” CHCl 2 NO) is and temporary blindness, and high concentrations can
a halogenated oxime used as a blistering agent in chemi- cause permanent corneal lesions and blindness (Sidell
cal warfare. Other halogenated oximes include diiodofor- et al., 1997; USACHPPM, 2001d). Inhalation or oral
moxime, dibromoformoxime and monochloroformoxime, absorption may cause respiratory tract irritation, dyspnea
but phosgene oxime is the most irritant of the group and and pulmonary edema. The noncardiogenic pulmonary
the only one considered a terrorist warfare threat. edema may occur after a several hour delay. Death is due
Phosgene oxime can be found as a liquid or as a colorless, to respiratory arrest.