Sarin ingestion

Nerve agent Chemical agent inhaled, absorbed through the skin, or ingested that causes interference with the neural synapses and overstimulation of the nervous system, which in turn leads to overreactivity in the muscles and malfunctioning of various organs. The primary agents are tabun, sarin, soman, and VX. 

Organophosphate and carbamate cholinesterase inhibitors (see Chapter 7) are widely used to kill insects and other pests. Most cases of serious organophosphate or carbamate poisoning result from intentional ingestion by a suicidal person, but poisoning has also occurred at work (pesticide application or packaging) or, rarely, as a result of food contamination or terrorist attack (eg, release of the chemical warfare nerve agent sarin in the Tokyo subway system in 1995). 

Casualties are caused primarily by inhalation, but can occur following percutaneous and ocular exposure, as well as by ingestion and injection. Sarin mixes easily with water, and people could be exposed by drinking contaminated water or via dermal contact with contaminated water. People could be exposed by eating contaminated food. Clothing can release sarin for 30 min, which could lead to exposure of other people. Sarin vapor is heavier than air, and can sink to low-lying areas. 

Miosis may also occur as a systemic feature, although more usually it follows direct exposure. This explains why, for example, modest dermal exposure may produce systemic features but not miosis. Abdominal pain, nausea and vomiting, involuntary micturition and defecation, muscle weakness and fasciculation, tremor, restlessness, ataxia and convulsions may follow dermal exposure, inhalation or ingestion of a nerve agent. Bradycardia, tachycardia and hypertension may occur, dependent on whether muscarinic or nicotinic effects predominate. If exposure is substantial, death may occur from respiratory failure within minutes, whereas mild or moderately exposed individuals usually recover completely, although EEG abnormalities have been reported in those severely exposed to sarin in Japan (Murata etal., 1997 Sekijima et al., 1997). 

Okumura T, Takasu N, Ishimatsu S, et al Report on 640 victims of the Tokyo subway sarin attack. Ann Emerg Med 28 129-135,1996 Persian Gulf Veterans Coordinating Board Unexplained illnesses among Desert Storm veterans. Arch Intern Med 155 262-268,1995 Petrucci N, Sardini S Severe neurotoxic reaction associated with oral ingestion of low-dose diethyltoluamide-containing insect repellent in a child. Pediatr Emerg Care 16 341-342, 2000... 

Like soman and sarin, tabun is a highly potent cholinesterase inhibitor. It is extremely toxic by inhalation, ingestion, and... 

These are related to organophosphorus insecticides and they include some of the most powerful poisons known to science. They act by inhibition of the enzyme acetylcholinesterase. Most act extremely rapidly within seconds and at very low concentration. Agonising death results from inhalation, ingestion or skin absorption. Best known are DFP, Tabun, Sarin and VX (Chapter 12.13). There may also be serious long-term effects arising from exposure to concentrations below levels which produce any immediately obvious effects. 

The toxin BoTx, produced by the anaerobe Clostridium botulinum, has the reputation of being the most toxic substance by weight known to humans, being at least 5000 times more toxic than sarin. Botulism is a disease of both humans and animals. Seven dilferent functionally related neurotoxins are produced by various strains (A-G). Botulism is essentially an intoxication, brought on by ingestion of the toxin produced by clostridial infection of food, usually incorrectly canned meats. Primary botulism, a direct infection, is rare and only affects infants in the human species. Botulinum intoxication can, however, be treated, and this modifies the toxicity considerably. It is estimated that less than 10 % of natural cases receiving ventilatory and antitoxin support are fatal. 

Sarin is rapidly absorbed through skin, eyes and mucosal membranes. It will penetrate clothing. It may be inhaled when in vapour form and may also be mixed with food or water for absorption via ingestion. 

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