Perils of poison control.

The young man's history of visual and auditory hallucinations caused his family great concern. He told his mother that he had swallowed rat poison to get rid of rats in his body after seeing one in his stool. Physicians found no sign of poisoning, but the family, with support from a social worker, insisted that admission to a psychiatric hospital was warranted. The situation went from bad to worse. The patient stopped responding to stimuli and soon lapsed into a coma. ACT scan showed swelling of his brain that intensified during the next couple of days, and in spite of all efforts, he passed away. On autopsy, remnants of bromethalin (a rodent poison) were detected in his brain and liver. A search of the man's home revealed bait impregnated with bromethalin. It seems the young man was serious about ridding himself of rats.

His was a tragic story, and just one of thousands of fatalities reported every year to Poison Control Centres across North America. And it is not the only one that involves bromethalin. The brightly coloured baits, which have a food-like flavours and fragrances, are often placed underneath radiators, near ovens, refrigerators, or trash containers. Children and pets can easily access these places--sometimes with catastrophic results. One of the roles of Poison Control Centres is to try to prevent such tragedies by asking physicians to report any cases that might involve poisoning of any sort. The centres also log and categorize all calls they receive directly from the public. The intent is to identify poisoning hazards and try to eliminate them.

Millions of calls are received every year, essentially in two broad categories. There are "information" calls seeking advice about the identity of a medication, about drug abuse, drug-drug interactions, food-drug interactions, or the safety of household products. But the bulk of calls are of the "exposure" variety. These range from concerns about exposure to potential toxins even when no immediate symptoms are apparent, to life-threatening situations after exposure to a known or unknown toxin. Unfortunately, despite the toxicological expertise of the health care professionals who receive the calls at the Poison Control Centres, the outcome is sometimes disastrous. But bringing some of these cases to the public's attention can potentially avert similar tragedies.

Picking wild mushrooms can be a dangerous business, as a 56-year-old man discovered. Cooking and eating the fungi he had picked in a forest landed him in an emergency room with nausea, diarrhea, and vomiting the next day. Doctors called a mycologist who questioned the patient and identified the mushroom as the aptly named "death angel," or Amanita bisporigera, which contains the heat-stable toxin alpha-amanitin capable of destroying the liver. After about three days, there is commonly a remission of symptoms, but it is a false remission. The patient was informed of this and told that his only hope was a liver transplant, but since he was feeling better, he refused to be listed for an urgent transplant. He died of liver failure two months after ingesting the mushrooms, which have been described as being very tasty. Just goes to show that you can't judge toxicity by taste.

And you clearly can't judge toxicity by whether a substance is natural or not. Witness the case of a four-year-old girl who was given a homemade herbal tea for fever and constipation by her grandmother. She also ended up in liver failure. A sample of the plant used was identified as Senecio longilobus, known to contain pyrrolizidine alkaloids that are highly toxic to the liver. As in the case of "death angel," the outcome was fatal.

Drugs are a prime cause of toxic reactions, usually due to improper use or medical errors. An elderly lady succumbed to a blood disorder brought on by methotrexate, a medication used to treat cancer or rheumatoid arthritis. The physician had actually prescribed meclizine to treat the patient's dizziness, but the pharmacist misread the prescription. Even the proper prescription can, of course, be mis-used. A 22-year-old woman suffered from excessive body hair due to an adrenal gland problem and decided to try laser hair removal. Since the procedure can be somewhat painful, her physician instructed her to apply a local anesthetic in the form of lidocaine cream from her toes to her waist and to wrap herself in cellophane to increase the drug's effect. On her way to the clinic, she had a seizure and passed out. She was transported to hospital but died a week later of lidocaine overdose.

And speaking of overdose, how about the case of the prisoner who gulped down a handful of haloperidol (an anti-psychotic) pills, about 100 nortriptyline (anti-depressant) pills, and followed this with a chaser of 30 aspirin tablets? Why? He told the prison clinic staff that he wanted to be sent to the psychiatry unit because they have turkey on Thanksgiving and the prison does not. The man refused attempts to wash out his stomach and administer charcoal to prevent absorption of the drugs. He never got to eat his turkey dinner or any other dinner--ever.

Sadly, many of the poisonings reported to Poison Control Centres are suicides, and insecticides are commonly used. Paramedics were called when a 23-year-old student lost consciousness, and they found a bottle of sodium sulfur arsenate nearby. Despite the administration of British anti-Lewisite, a classic arsenic antidote, he died. So did a man who had been spraying the organophosphate insecticide malathion around his yard and spilled some in an enclosed garage. He tried to clean up the spill but soon started to feel sick. He was taken to emergency where the usual drugs used to treat organophosphate poisoning--atropine and pralidoxime--were administered. All to no avail.

This is just a smattering of the thousands of fatalities reported every year to Poison Control Centres. And the really tragic part of all of this is that most of these deaths are preventable.

Popular science writer, Joe Schwarcz, MCIC, is the director of McGill University's Office for Science and Society. He hosts the Dr. Joe Show on Montreal's radio station CJAD and Toronto's CFRB. The broadcast is available on the Web at www.CJAD.com. You can contact him at joe.schwarcz@mcgill..ca.