Summer Feline Toxins

Rachel Kinney, CVT, VTS (ECC), discusses various lily toxicities and their treatments as well as bugs that can cause harm to our feline patients in the summer.

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With the arrival of summer and that warm weather, for which us Pacific Northwesterners are starved, comes an increase in the cases of specific cat toxins we see. The flowers are blooming and the bugs are out in full force! These flowers and bugs may seem pretty harmless, but their ability to thrive can have a detrimental and even deadly direct effect on our feline friends.

Lilies need to come with a BIG warning label. They are such beautiful flowers that love to bloom in the warm summer months and are usually unassuming to the average pet owner. The most common way cats are exposed to lilies is by their owners bringing the cut flowers or plant into their home. Outdoor cats can also be exposed to any lilies that are growing outside. The most dangerous lilies are those of the Lilium or Hemerocallis genus. These are known as “true lilies” and include the species tiger, day, Asiatic hybrid, Easter, Japanese Show, rubrum, stargazer, red, Western, and wood lilies. These are the species than can lead to acute renal failure and death in cats, although the toxic element has still not been identified. Cats love to chew on flowers and plants, and it only takes a bite or two of these toxic flowers, their petals, and stems to start the process.

Signs of toxicity initially can be vague (lethargy, inappetance, polydipsia, polyuria, and vomiting) or even nonexistent. In the advanced stages of toxicity, halitosis, dehydration, painful kidneys, and anuria are signs of acute renal failure occurring. The sooner treatment is initiated the better the prognosis. Treatment often consists of trying to induce vomiting on the cat if within the first couple hours of ingestion (we all know the gamble this can be!) followed by administering activated charcoal orally (another fun project in a cat!) to eliminate as much of the toxin that can be absorbed as possible. I take extra care when inducing emesis and administering oral liquids to cats as they are much more likely than dogs to struggle during the processes and aspirate. This is followed by 48 hours of aggressive IV fluid diuresis. As the cat’s technician, I monitor his urinations, pain score, mental status, hydration, electrolytes, and kidney values very closely. I also want to be sure to frequently check the cat’s respiration rate and effort as these patients are usually on high rates of IV fluids and can be more susceptible to fluid overload.

Another life threatening lily out there is the lily of the valley (Convallaria majalis). This species of lily does not cause kidney failure but instead can cause bradycardia, severe cardiac arrhythmias, hyperkalemia, seizures, and death via a cardiac glycoside toxin. Ingestion of this plant also requires immediate veterinary attention for decontamination. Monitoring the cat’s ECG closely will allow me to watch for changes in the heart rate, rhythm, and signs of hyperkalemia (tall, peaked t-waves progressing to loss of p-waves) so medical intervention can take place immediately if seen.       

The last types of lilies I want to discuss are not “true lilies” and do not cause life-threatening conditions but still have toxic properties to cats. The Peace, Peruvian, and Calla lilies all contain insoluble oxalate crystals that can cause oral irritation.  Cats that chew on or ingest these types may be seen drooling or foaming at the mouth, pawing at their mouth, or vomiting. So although these symptoms tend to be transient and do not always require medical intervention, they are still producing uncomfortable and undesirable effects in our feline companions. My rule of thumb is, if it contains the word lily, keep it away from cats!

That brings me to the bugs that come out of hiding to also enjoy the warm weather. Mainly, the ones that love to feed off our pets: fleas! There are many choices of topical flea products for pets, but cats are much more sensitive to their effects than dogs. Those containing pyrethrins and pyrethroids can cause muscle tremors and seizures in cats.

Exposure usually occurs when these products are used off label on cats. Treatment on cats exhibiting signs of toxicity begins with decontamination by bathing to remove any remaining product from the fur and skin to prevent continued absorption. Great care must be taken during the bathing as the cats are incapacitated and scared. First we must avoid getting soap and water into their eyes, ears, nose, and mouth. This is to prevent ocular ulcers in a patient that may not be blinking normally, vestibular symptoms in an already neurologically impaired patient, and pneumonia in a recumbent patient. Once bathed it is important to dry the cat off as much as possible and provide warming as necessary to prevent hypothermia.

The rest of treatment is all supportive and nursing care. Intravenous fluids, muscle relaxants and/or anticonvulsants, pain medications, and nutritional support if needed are the main points of the supportive care while the cats are debilitated.  There is usually a lot of nursing care involved with these cases as well. This includes changing their recumbency every 4 hours if they are immobile to prevent atelectasis, pneumonia, and pressure sores and lubricating their eyes every 4-8 hours if not blinking sufficiently to prevent ocular ulcers. It is also often required to express their urinary bladders as necessary if they are experiencing urine retention or change out their bedding and clean any urine soaked areas to prevent urine scalding if they are urinating on their own. These patients will often need assistance in eating until they regain normal proprioception. And for the severely affected patient, reducing the amount of stimuli around the cat is very important. Loud noises, excessive movement, and bright lights can all exacerbate the symptoms.

Another bug we see out and about more in the summer months is the spider. Although the majority of spiders are non or minimally venomous, the black widow spider and the brown recluse spider are the two that are quite poisonous and their bite is toxic to pets. Given a cat’s often curious and playful nature, exposure usually occurs when a cat is “hunting” one of these venomous spiders.

The black widow spider can be found throughout America. Its venom contains a neurotoxin that can cause severe muscle pain, ataxia, tremors, and paralysis. Treatment includes administration of the antivenom when available as well as similar supportive and nursing care as used for pyrethrin toxicities. 

The brown recluse spider is only found in the south and lower mid-west, so this is not a toxin we see here in the Pacific Northwest. Its bite can vary greatly in venom potency and toxic symptoms. Based on the amount of toxin received, cats that are bitten can develop severe and sometimes necrotic wounds at the bite location, bleeding disorders, and even damage to the liver or kidneys as a result. Because there is no antivenom for the brown recluse spider, treatment is all supportive care. Affected cats can be very painful and require excellent pain management. Wound care and antibiotic therapy is used to treat the bite itself. Liver protectants and diuresis should be implemented in cases of hepatic and renal insult, and clotting times and PCV/TS should all be evaluated to determine if plasma, packed red blood cells, or both are needed.

Cats depend on their owners to keep them safe, but they can’t protect them from things if they don’t know they are dangerous. Through education of our clients and the community, we can hopefully help decrease the occurrences of all of these summer toxins. 

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Mallory Clark's picture

Brown recluses are also found in Michigan, so it's not only the lower Midwest that they can cause issues.

Jackie Moan's picture

Laser therapy can be an amazing tool when dealing with the tissue necrosis seen with a brown recluse. Since pain management in cats esp can be tricky, lasers can offer a lot when trying to get the inflammation and pain under control. Just a side thought.
Also, I'm guessing snakes are not a huge issue in the Pacific however, should be mentioned as they are a HUGE headache for the veterinary professionals in the southern states and can be seen during the warmer months (I only mentioned snakes, b/c you mentioned bugs), and with cats they too can be a headache since cats tend to have more of a reaction to antivenom then the canine counterpart. (What? cats having a reaction to a drug? Never!
Keep up the good work, my students love this site!