Page 109 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

76 SECTION | I General

VetBooks.ir TABLE 5.2 LD 50 for Mustard Gas are present. Topical doxycycline and silibinin have been
shown to decrease ocular injury (Goswami et al., 2016).
Corneal transplants have been performed on some human
Species
LD 50 (mg/kg)
Route
patients with good results and may be considered for
Human Oral 0.7 some valuable animals (Blodi, 1971).
Dermal 100 Several general dermal decontamination methods can
help reduce the toxicity of mustard gas. Bathe animals
Mouse Dermal 92
with copious amounts of soap and water. Dermal decon-
SQ 20
tamination needs to be implemented quickly, as once
Rat Oral 17 mustard has reacted with the skin, it cannot be easily
removed (Sidell et al., 1997). Many therapies have been
Dermal 5
recommended to neutralize dermal mustard exposures:
SQ 1.5
2.5% sodium thiosulfate solution (Garigan, 1996), dilute
Source: Data from Lewis, R.J., 2000. Sax’s dangerous properties of (0.5%) hypochlorite solution (Borak and Sidell, 1992),
industrial materials, 10th edn. Van Nostrand Reinhold Company, New clay, such as Mineral Cationic Carrier (MCC: Kodona;
York, NY; RTECS, 2006. Registry of Toxic Effects of Chemical
Substances. National Institute for Occupational Safety and Health. Zagreb, Croatia) (Vucemilovic et al., 2008), silibinin
Cincinnati, OH (CD Rom Version). Edition expires 2006; provided by (Tewari-Singh et al., 2012), silver sulfadiazine, dexameth-
Thomson MICROMEDEX, Greenwood Village, CO.
asone, and diclofenac (Dachir et al., 2004). Monitor for
dermal effects, which are delayed and progressive.
Dermal lesions behave like a chemical burn or radiomi-
acidosis are seen. Seizures appear to occur only following
metic effect. Healing can take weeks to months and infec-
extremely high acute doses (Sidell et al., 1997).
tion is common (Borak and Sidell, 1992). Removal and
Leukopenia, thrombocytopenia, pancytopenia, and
debridement of closed blisters is controversial. Blisters
anemia have all been reported due to depressed myelopoi-
should be left intact until they rupture spontaneously or
esis from destruction of precursor cells in the bone mar-
unless they are extremely large or inhibit motion
row (Borak and Sidell, 1992). Bone marrow aplasia can
(Roberts, 1988). Tetanus toxoid should be given to all
be seen in severe cases. Secondary to bone marrow dam-
equine and ovine patients. Tetanus prophylaxis of other
age, overwhelming infection can result in death (Sidell
species should be determined on a case-to-case basis.
et al., 1997).
Monitor for coughing and respiratory distress. If respi-
Mustard gas is considered both carcinogenic and
ratory abnormalities occur, monitor arterial blood gases
neoplastic. Mustard gas has caused carcinomas in the
and/or pulse oximetry, and thoracic radiographs. Thoracic
skin, appendages, lungs, thorax and blood (leukemia) of
radiographs may show an infiltrate within the first 2 days
rats and mice via both inhalation and IV exposure
(Smith, 1999). Nebulization of 2.5% sodium thiosulfate
(RTECS, 2006).
may help neutralize the mustard gas. N-acetylcysteine
(Mucomyst) is also a potential mustard gas antagonist
(Garigan, 1996). Intertracheal administration of tissue
Treatment
plasminogen activator has been shown to improve oxy-
Move animal into fresh air. Do not induce emesis. genation in rats (Veress et al., 2015). Administer oxygen
Activated charcoal administration after oral ingestion is and inhaled beta agonists if needed. Intubation and venti-
controversial. It appears to have some beneficial effects if lation may be needed. Melatonin can be beneficial in
administered within 1 h of ingestion. Sodium thiosulfate acute mustard toxicosis. It is a scavenger of both oxygen-
has been used as a “mustard scavenger” and giving 2% and nitrogen-based free redicals and regulates gene
sodium thiosulfate solution orally may help in cases with expression of antioxidant enzymes (e.g., SOD, GSH-Px)
ingestion exposures (Borak and Sidell, 1992). If signs or (Tan et al., 2007). Melatonin also decreases inflammation
symptoms of esophageal burns are present, consider by blocking proinflammatory cytokines and sparing ATP
endoscopy to determine the extent of injury. Perforation production (Tan et al., 2007). Combinations of parenteral
and stricture formation could result. dexamethasone, promethazine, vitamin E, and heparin
Flush eyes with tepid water for at least 15 min. After have shown protective effects against mustard gas poison-
flushing, instill 2.5% sodium thiosulfate to help neutralize ing in laboratory animals (Vojvodic et al., 1985; Requena
the mustard. Time to decontamination is very important et al., 1988).
with ocular exposures. Mustard droplets disappear from Monitor CBC with platelets for 2 weeks after expo-
the eye very quickly, and late flushing of the eye gener- sure. Leukopenia develops at 7 10 days following a
ally provides no benefit (Sidell et al., 1997). Topical anti- severe acute exposure (Garigan, 1996). Prophylactic anti-
biotics and mydriatics should be used if corneal lesions biotics are not recommended, but a broad spectrum