AVMA 2018: Pet Poisoning? Don't Forget These Questions

According to Renee Schmid, DVM, consulting veterinarian in clinical toxicology at Pet Poison Helpline in Bloomington, Minnesota, veterinarians dealing with a potential toxin exposure should evaluate the patient and the toxin completely before initiating treatment.

Presenting at the 2018 AVMA Convention in Denver, Colorado, Dr. Schmid discussed how to assess a poisoned patient appropriately to best understand not only the risks associated with the toxin but also those associated with specific patients and any preexisting conditions they might have.

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The first thing to determine is whether the patient is stable, she said, so be sure to assess the patient’s vital signs, hydration status, and neurologic status. Laboratory testing should be performed, as indicated.

Reviewing the patient’s current and past medical history, including medications, will help you decide what treatments the patient can receive safely. Long-term medical conditions can also affect the signs of some toxicities, Dr. Schmid added.

Knowing the patient’s signalment can also provide useful information to help guide therapy. Certain toxins may affect certain animal species, Dr. Schmid said, noting how lilies are toxic to cats but not to dogs. Breed-specific issues also exist. For example, brachycephalic canine breeds are at increased risk of aspiration if vomiting is induced, she noted. The patient’s age is important to know as well, because very young or very old animals may experience altered toxicity effects. Puppies and kittens do not have a fully functional hepatic system until they are about 12 weeks old, she added.

“The difference between a toxicity and a nontoxic ingestion is often a very thin line,” Dr. Schmid said, so accurate assessment of a patient’s body weight is also critical to allow for proper assessment of toxicity risk, especially for ingested toxins.

Knowing the toxin is also important to help guide treatment. For example, if a cat has reportedly been exposed to lilies, it is crucial to try to identify which type of lily was involved. “Just because it has ‘lily’ in the name doesn’t mean it is toxic,” Dr. Schmid said. Only true lilies (Lilium spp) and daylilies (Hemerocallis spp) are toxic to cats—calla lilies (Zantedeschia spp) and peace lilies (Spathiphyllum spp), which are not true lilies, are nontoxic, she stressed. Similarly, if a dog has ingested gum, attempt to identify the exact brand and flavor, because this may help you determine whether it contains xylitol.

Knowing the route of toxin exposure is also important, because this helps in determining the toxicity risk and severity. Some toxins may result in different degrees of toxicity or have different treatment needs, depending on the route of exposure, Dr. Schmid explained. For example, was the patient’s skin exposed to a liquid toxin that the animal then also licked?

Also attempt to determine how much toxin the patient was exposed to. “The dose makes the poison,” Dr. Schmid stressed, so it is important to find out how much toxin is involved. Even a vague estimate is helpful, she added—for example, knowing whether the patient ingested a full bowl of a liquid toxin or just a few licks of it.

How long ago was the animal exposed to the poison? This timeframe can help guide therapeutic decisions, Dr. Schmid said. Induction of vomiting is a reasonable treatment option if a patient ingested a toxin 20 minutes ago, she said, but not if the toxin was ingested 6 hours ago.

The timeframe also helps in assessing whether clinical signs are likely to develop. For example, if a patient was reportedly exposed 4 hours ago to a toxin that would typically cause signs within a 1- to 2-hour timeframe, but has not yet developed any clinical signs, a toxic exposure probably did not occur.

Knowing the location where the exposure occurred can also help you identify other potential confounding factors as well as the potential severity of a toxin. Other factors should also be investigated, Dr. Schmid said. For example, was the exposure accidental or malicious? Were any other animals also potentially involved?

Discussing some ideal treatments for toxicity management, Dr. Schmid stressed that some of the best options might simply be substances that are readily available at home or in the clinic. For example, in the case of ocular exposure, an eye wash is the best treatment option, she said, and tap water is the second-best choice. In contrast, she noted, studies have suggested that saline does not decontaminate the eye adequately after exposure to alkaline chemicals. And, for dermatologic exposures, a degreasing agent like dishwashing solution is a better option than any type of shampoo, Dr. Schmid said.

To induce vomiting after toxin ingestion, she stressed that apomorphine (0.03 mg/kg IV or 0.04 mg/kg IM) is the best choice for most poisoning cases in dogs, and xylazine (0.44 mg/kg IM) is typically the best option for cats.

Overall, Dr. Schmid urged veterinarians not to become caught up in an owner’s anxiety when managing cases of poisoning. “Don’t let their panic become your panic,” she concluded. “Take a step back, ask questions, and take things one step at a time to prevent doing things you may regret later.”

Dr. Parry, a board-certified veterinary pathologist, graduated from the University of Liverpool in 1997. After 13 years in academia, she founded Midwest Veterinary Pathology, LLC, where she now works as a private consultant. Dr. Parry writes regularly for veterinary organizations and publications.