How to Take a Toxin Exposure History
Toxicology Talk is written and reviewed by members of the American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center (APCC). The mission of the APCC is to help animals exposed to potentially hazardous substances, which it does by providing 24-hour veterinary and diagnostic treatment recommendations from specially trained veterinary toxicologists. It also protects and improves animal lives by providing clinical toxicology training to veterinary toxicology residents, consulting services, and case data review. The ASPCA APCC includes a full staff of veterinarians, including board-certified toxicologists, certified veterinary technicians, and veterinary assistants, and its state-of-the-art emergency call center routinely fields requests for help from all over the world, including South America, Europe, Asia, and the Pacific Islands. You can also download their mobile app.
“My pet just ate this! What do I do?”
Pets tend to eat anything and everything. Some exposures may be more of a concern than others. Getting the details of the exposure is very important. Learning how to take an exposure history will help in gathering the information necessary to determine what treatments are needed. A triage form can be used to record the information outlined in this article.
When a pet owner calls about a pet ingesting a potentially toxic substance, first ask how the animal is doing. If the animal is bleeding, not breathing, or is having a seizure, medical attention is needed right away. Nothing can be done over the phone in these situations. Advise the owner to remain calm and bring their pet in immediately or take the pet to the nearest open general or emergency veterinary facility.
If the pet is not experiencing these life-threatening symptoms, the next questions to ask are the pet’s breed, age, weight, and health history. The signalment is important when assessing a potential toxic exposure.
Emesis is commonly recommended after an ingestion of a possible toxic substance; however, emesis may or may not be indicated based on the animal’s signalment and current status. Emesis is generally not recommended if the pet is already vomiting or showing clinical signs, if a corrosive substance was ingested, if the pet had recent abdominal surgery, or if the pet has a poor health history (e.g., seizures).
Product details are important when collecting the exposure history. Details from the product label, if the pet owner has it, provide the most helpful and reliable information. In the United States, products that are regulated by the Environmental Protection Agency (EPA) list a registration number (EPA Reg number) on their labels. In Canada, these products have a PCP number instead. Some common products that have an EPA Reg or PCP number are fertilizers, pesticides, herbicides, rodenticides, and some household products. The owner can find the EPA Reg number on the label around the manufacturer details or the ingredients. If the owner no longer has the label but purchased the product, ask if they can go back to the store to possibly identify the product. If the product was placed by a pest control operator or landscaper, ask if the owner has a receipt for the services that contains information on what product was used. EPA Reg and PCP numbers are important when contacting an animal poison control hotline.
If a human-use medication, either over the counter or prescription, was involved, the name and strength are important details to collect. The owner can find this information on the bottle label. The form of the medication is also important because it can affect the absorption time and onset of clinical signs. Some common forms of medication are tablets, capsules, softgels, chewables, liquids, topicals, and powders. Liquids tend to get absorbed very quickly, and some tablets can be extended release.
If the label is no longer available or legible and the medication was prescribed, the owners can call the prescribing pharmacy to determine the medication details. If that is not an option or the product was an over-the-counter medication, the imprint code (the numbers and letters that are printed on the pill) can be used to help in identification of the product. The staff at a poison control center or local pharmacy may be able to identify the product based on the imprint code, which can be used to look up medication name and strength.
Many medications contain multiple active ingredients (e.g., multivitamins, cold and flu medications, supplements), so ask the owner to read you all of the ingredients. If the product is a cold medication, it may contain pseudoephedrine, which can cause serious cardiovascular and central nervous system stimulation. Identification is required to purchase pseudoephedrine, so ask the owner if they remember having to show any identification when they bought the medication.
Some medications that are flavored, chewable, or compounded may contain xylitol, which can cause severe hypoglycemia and liver failure in dogs. Ask the owner to look specifically for xylitol listed as an ingredient in these types of medications.
If a veterinary-prescribed medication was involved, the name, strength, and prescription history are important in determining the risk assessment. Ask whether the pet is currently on the medication or has been in the past. If the owner has been giving the medication as prescribed, knowing the prescribed dosage can help determine how much may be missing. If multiple medications are involved, drug interactions could also be a concern.
Once product details are available, the amount ingested is needed to determine the risk for toxicosis. Try having the pet owner estimate the worst-case scenario. If some of the product is left, it could be weighed to estimate the amount missing (e.g., fertilizers, chocolate, rodenticides).
Some liquid substances are dispensed with syringes, droppers, or cups to be used in measuring the dose. These are helpful tools when estimating the amount of liquid missing.
If the pet ingested a plant, identification of the plant is necessary to determine the risk. Plant identification can be difficult when the pet owner is not sure what the plant is. Pet owners can look for pictures online, but information obtained this way may not always be accurate. Garden nurseries can sometimes help with identification.
In addition to information about the pet and the product, other important details should be collected, such as the timing of the exposure. Ask when the exposure happened and whether anyone saw it. Unfortunately, exposures often occur when the owner is not with the pet (e.g., when the owner is sleeping or at work). If the exposure wasn’t witnessed, ask about the time frame of the exposure, including the earliest and latest times it may have happened. Comparing the exposure time frame to the expected onset time for development of clinical signs can help determine the course of treatment for the animal. For example, if a dog ingested chocolate 24 hours ago, emesis would no longer be effective, and if an animal ingested a rapid-acting medication many hours earlier but has not developed clinical signs, treatment may not be needed.
Also ask the owner if more than one pet was involved. Multiple pets can drastically change the exposure and treatment plan. If pets may have shared what was ingested, the worst-case scenario must be determined for each pet and the treatment plan customized accordingly.
If the owner suspects poisoning but doesn’t know what may have been ingested, ask the owner where the suspected exposure took place. If the pet was outside, many things could have been ingested (e.g., fertilizers, mole/gopher baits, mushrooms).
Once all the above information has been collected, a treatment plan can be developed. Any medical treatment that has already been administered by the pet owner at home, such as inducing emesis, needs to be taken into account.
Commonly, inducing emesis and/or administering activated charcoal is recommended in cases of possible toxicant exposure. These treatments may not be needed depending on the situation and patient. As many veterinary professionals know, cats sometimes do not vomit when we want them to. Hydrogen peroxide (3%) is commonly recommended for inducing emesis in dogs but has not been shown to be effective in cats. Inducing emesis in cats at home should never be recommended. Additionally, rodents, rabbits, birds, horses, and ruminants cannot safely vomit, so emetics should not be used in these cases. Medications that can be used for emesis at the veterinary clinic include apomorphine hydrochloride and xylazine.
Activated charcoal is like a magnet; it attracts and holds toxins to its surface to carry them through the gastrointestinal tract without being absorbed by the body. Activated charcoal is administered when an animal ingests certain products such as organic poisons, chemicals, or bacterial toxins. Toxins that undergo enterohepatic recirculation may require multiple doses of activated charcoal. Hypernatremia is a possible downside of activated charcoal administration, so serum sodium must be monitored when giving activated charcoal.
Cathartics enhance the elimination of activated charcoal from the body. If cathartics are not used, the toxin bound by the activated charcoal can eventually be released and absorbed, delaying the development or prolonging the course of clinical signs. Cathartics would not be recommended if the animal has diarrhea or is dehydrated.
Once the exposure details are collected and the animal has been stabilized, other diagnostics and treatments can be considered. Blood work, radiographs, and fluid therapy may be recommended, depending on the exposure information. Calling a professionally staffed animal poison control hotline can help hospital staff develop a treatment plan.