6-12 September 2013 #672

Poisoned environment

Dhanvantari by Buddha Basnyat, MD

One of the deadly chemical agents used in the gas attack on a suburb of Damascus last week was Sarin. This is an organophosphate compound which is also extensively used as pesticides in South Asia, including Nepal.

What may not be known to readers is that organophosphate ingestion is the most common way to commit suicide in our part of the world. When you read of a suicide, either of cotton farmers in India or students who failed exams in Nepal, they will mostly have taken pesticide. Sadly, this poison is available over the counter at ordinary shops, sometimes sharing shelf space with food items.

The 23 children who died in Bihar after eating free school lunch in August were poisoned by food laced with organophosphates. The Bhopal gas disaster in 1984 that killed nearly 4,000 people in India was caused by a leak in a pesticide factory owned by Union Carbide, although the gas in that case was methyl isocyanate.

There is no enforced regulation in India or Nepal of the sale of organophosphate pesticides. The perpetrators of violence in Syria are allegedly using this compound to deliberately kill civilians, but for decades the misuse of organophosphates has caused untold tragedy in our part of the world.

In most major hospitals in Nepal, half a dozen patients at any given time are admitted with organophosphate poisoning. As the doctor takes the history and examines the patient with this affliction, a truly preventable human tragedy unfolds. Many patients are young women who have tried to inflict self-harm because they had a quarrel with their husbands, or were abused by in-laws.

Local brands of organophosphate compounds go by names like nuvan, metacid, dalf, and suchlor. Medical students use the acronym ‘SLUDGE’ (salivation, lacrimation, urine incontinence, diarrhoea, gastrointestinal cramps and emesis or vomiting) to help remember the effects of this pesticide in patients. The chemical inhibits the natural destruction of an enzyme called acetylcholine in the human body which then sets off a cascade of secretions.

Organophosphate has been classified as a chemical or bioterrorism agent, especially after the sarin gas attack in the Tokyo subway in 1994 when the victims complained that “their world went black” followed by all the symptoms of ‘SLUDGE’. Sarin is a vapour form of organophosphate that first causes injury to the eyes leading to pupillary narrowing and partial blindness after exposure. These symptoms can potentially be fatal depending on the amount ingested or inhaled and just how promptly the treatment was started. The main cause of death is respiratory depression triggered by the undestroyed acetylcholine which is widely distributed in the brain.

The most essential drug used to treat organophosphate poisoning is derived from plants (datura, deadly nightshade, mandrake, among others) from the Solanaceae family and is called atropine. Atropine effectively blocks the effects of acetylcholine. Ironically, the word atropine comes from Atropos, one of the three Fates in Greek mythology, who decides how someone should die. In the case of organophosphate poisoning, atropine is clearly a life-saving antidote. It is easy to imagine how atropine could be in short supply in war-torn Syria.

In South Asia the organophosphate poisoning tragedy can be prevented in large measure if there is political will. So long as a teenager that has fared badly in her SLC exams can go to a general store and easily buy organophosphate pesticides, we will continue to witness these preventable tragedies unfold here in future.