Mustard ocular effects

Table 1. Ocular effects of sulfur mustard in dogs 6...

Petrali, J., Dick, E., Brozetti, J., Hamilton, T., Finger, A. (2000). Acute ocular effects of mustard gas ultrastructural pathology and immunohistopathology of exposed rabbit cornea. J. Appl. Toxicol. 20 (Suppl. 1) S173-5. 

Morad, Y., Banin, E. et al. (2005) Treatment of ocular tissues exposed to nitrogen mustard beneficial effects of zinc desferrioxamine combined with steroids. Invest Ophthalmol Vis Sci 46(5) 1640-1646. 

Javadi, M.A., Kazemi-Moghadam, M., 2000. Ocular effects of sulfur mustard poisoning. In Cheraghali, A.M. (Ed.), Prevention and Treatment of Complications of Chemical Warfare Agents Chemical Warfare Research Center, Tehran, Iran, pp. 82-101. 

Sulfur mustards (designated H [mustard], HD [distilled mustard], and HT [HD and T mixture]) do not present acute lethal hazards. Their principal effect is severe blistering of the skin and mucous membranes. Epidemiological evidence indicates a causal relationship between exposure to mustard agent at high concentrations and the development of chronic nonreversible respiratory disorders, such as chronic bronchitis and asthma, and ocular diseases, such as delayed recurrent keratitis and prolonged, intractable conjunctivitis (IOM, 1993). Sulfur mustard has been classified as a known human carcinogen based on evidence of in-... 

War I. More recent use occurred in Middle East conflicts. Its oily nature makes it persistent on surfaces it contacts. Because sulfur mustard exerts toxic effects following dermal, ocular, and inhalation exposure, its use necessitated fiill body protection which, in tmn, required the development of protective clothing and significant changes in warfare operations. 

Acute lethality data in animals are summarized in Table 8.7. Based upon the animal data, interspecies variability in the lethal response to sulfur mustard vapor is less than an order of magnitude. For nonlethal effects, the animal data suggest that test species exhibit signs of toxicity that are qualitatively similar to humans when acutely exposed to sulfur mustard vapor. Ocular and respiratory tract irritations are clearly evident in studies using dogs, rats, mice, rabbits, and guinea pigs. 

Amir, A., Kadar, T., Chapman, S., Turetz, J., Levy, A., Babin, M., Ricketts, K., Brozetti, J., Logan, T., Ross, M. (2003). The distribution kinetics of topical C-sulfur mustard in rabbit ocular tissues and the effect of acetylcysteine. J. Toxicol. 22 201-14. 

Bossone, C., Newkirk, K., Schulz, S., Railer, R., Gazaway, M., Shutz, M., Clarkson, E., Estep, S., Subramarian, P., Castro, A. Clinkscales, J., Lukey, B. (2002). Effects of prednisolone acetate on ocular sulfur mustard injury in a rabbit model. Technical report, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 1-22. 

Ocular exposure can cause pain, lacrimation, comeal ulceration, swelling, blepharospasm, and blindness as the eyes are very sensitive to the effects of mustard gas (Borak and Sidell, 1992 Dacre and Goldman, 1996 Garigan, 1996 NATO, 1973). Pathognomonic signs of mustard gas poisoning include poreelain-white areas in the episcleral... 

Ocular, percutaneous, inhalation, ingestion, and injection are all possible routes of exposure. Effects may be local, systemic, or both. All of the nitrogen mustards are oily liquids that are colorless to pale yellow and evaporate slowly. They are more dangerous than sulfur mustard but, like sulfur mustard, they are derivatives of ammonia. The most toxic and most volatile of the three nitrogen mustards is HN-2, but HN-3 is used more because it is stable. 

The second exception is that while an antidote is available for systemic effects of Lewisite exposure, there are no antidotes for nitrogen mustard or sulfur mustard toxicity, with one minor caveat if given within minutes after exposure, intravenous sodium thiosulfate may prevent death due to sulfur mustard exposure (25). Otherwise, the medical management for skin, ocular, and respiratory exposure is only supportive. One guideline physicians can follow is to keep skin, eye, and airway lesions free from infection. 

Recognizing the fact that ROS play a role in the pathogenesis of mustard-induced ocular injuries, compounds that inhibit the formation of ROS or prevent their toxic effects would be beneficial in the treatment of mustard-induced ocular injuries. The topical application of low concentrations of Zn/DFO or Ga/DFO after comeal exposure to nitrogen mustards markedly reduced conjunctival, comeal, iris, and anterior chamber injury. In the cornea, the healing of epithehal erosions was faster, the long-term opacification was reduced, and the levels of neovascularization were lowered. In the anterior chamber, decreased inflammation and better maintenance of intraocular pressure were achieved. Cataractous changes were also notably milder (Banin et al., 2003). 

A combination of topically applied Zn/DFO and dexamethasone, by virtue of their additive inhibitory effects on free radical formation and inflammation, reduced nitrogen mustard-induced injury to ocular anterior segment stmctures. Furthermore, the combination treatment of Zn/DFO and dexamethasone resulted in a speedier comeal reepithelization, less-severe comeal neovascularization, and the intraocular pressure was not as severely elevated as in the saline or the Zn/DFO- or dexamethasone-alone groups (Morad et al., 2005). 

Medical impact of chemical weapons Exposure to mustards is associated with development of chronic health problems including chronic neurophathic pain [14] increased susceptibility to cancers [15-21] possible defective spermatogenesis [22] ocular injury [23-29] skin lesions [30-34] and respiratory disease [35-45]. During our war with Iraq, reports from Iranian combat aid stations, field hospitals in battle zones and reports by civil authorities, where non-combatants had endured chemical warfare (CW) exposure, more then 100,000 military and civilian personnel had received treatment for acute effects of CW agents [46]. 

Individuals who sustain acute ocular injury due to high-dose mustard exposure may experience difficulties even after the initial effects of the injury have subsided. Recurrent or persistent corneal ulceration can occur after latent periods of 10 to 25 years. Chronic conjunctivitis and comeal clouding may accompany this delayed keratopathy. Anecdotal accounts suggest that low-dose exposure also causes increased sensitivity to later exposure to mustard, although the existence of increased sensitivity is difficult to substantiate with available scientific evidence. ... 

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