Antifreeze Toxicity

By Dr. Beth Guerra

Ethylene glycol, the main ingredient in antifreeze, has long been known to be toxic to household pets. Exposure is usually from puddles under a leaking car or a container in the garage that has been spilled or chewed up by a pet. The minimum lethal dose is only around 2.5 tablespoons for a 20 lb dog or just one teaspoon in a seven-pound cat. The toxic component is not the ethylene glycol itself, but rather the metabolites that form when it is broken down by the liver.

There are three recognized stages to antifreeze poisoning:

Stage 1 (within 30min to 12 hours after ingestion) The pet usually experiences nausea, vomiting, lethargy, or neurological signs and can appear ‘drunk’. Increased thirst and urination may also occur.

Stage 2 (12 to 24 hours after ingestion) An increased respiratory and heart rate may be noted.

Stage 3 (24 to 72 hours after ingestion in dogs, 12 to 24 hours in cats) One of the byproducts of metabolism combines with calcium in the body to form calcium oxalate crystals that damage the kidneys. These crystals can be detected in the urine and can help confirm the diagnosis. A severe metabolic acidosis occurs as well. Oliguric kidney failure develops, characterized by a lack of urine production, can develop at this time. Additional symptoms may include nausea, vomiting, and severe depression.

There are several tests that can be used in dogs to test for ingestion of antifreeze. Some test for ethylene glycol itself, others for the metabolic byproducts. We do have screening tests at ACCES but usually submit the sample to a human hospital for confirmation.

If ingestion was suspected but not witnessed, it is always beneficial to run a test. Treatment varies based on time of ingestion and symptoms at presentation. If ingestion was within 30 minutes and there are no clinical symptoms, decontamination can be attempted with induction of vomiting. In the case of a positive results and symptoms, immediate care should be instituted to avoid impending renal failure. Therapy includes aggressive fluid therapy as well as IV infusions of 4-MP. If 4-MP is not available, intravenous ethanol also works to prevent metabolism of the ethylene glycol to its toxic compounds but causes more side effects. Daily monitoring of blood pH, fluid input, and urination is essential. Symptoms such as vomiting, seizures, or respiratory distress should also be anticipated and treated. Therapy is continued until the test is no longer positive; in some cases this may be several days to weeks. In dogs, the prognosis is favorable if treatment is within 12 to 16 hours and the kidney values are not elevated. In cats, treatment should be within three hours. Once there are signs of kidney failure and crystals, prognosis is grave. The mortality rate in dogs is reported to be 59-70% and is thought to be even higher in cats.

If you have witnessed your pet drink antifreeze, or think exposure has occurred, contact National Animal Poison Control Center; (888) 426-4435 or your veterinarian immediately.

Salmon Poisoning Disease

By Beth Guerra, DVM

Salmon poisoning disease (SPD) has been identified in the Pacific NW down through northern California. Because of the name, most people think of it as some sort of food poisoning obtained by eating bad salmon. The organism responsible for SPD is actually a small microscopic (rickettsial) organism located within the immature form of a fluke that colonizes the flesh of salmon. If raw fish are ingested by dogs, the fluke will mature within the intestine and release the rickettsial organism that causes disease.

Symptoms usually occur within five to seven days of ingestion of infected fish and may include fever up to 104F, vomiting, diarrhea, loss of appetite and weakness. The body’s lymph nodes are usually enlarged and can be palpated on exam. Diagnosis is often made by identifying the fluke eggs on a fecal exam, but a CBC/chemistry, abdominal x-rays or ultrasound should be performed to rule out any concurrent diseases.

Patients are generally hospitalized for aggressive supportive care due to rapid onset of symptoms. Diarrhea and vomiting can be severe or become bloody, so fluid support is required. Medications include a tetracycline antibiotic to eradicate the rickettsial organism as well as a general deworming medication to treat for the flukes. If SPD is caught early and treated appropriately, the prognosis is good and patients usually recovery fully. 

Are these foods REALLY toxic?

By Beth Davidow, DVM DACVECC

There are a number of foods that are now known to be toxic to pets. I tend to wonder each time I hear of a new toxicity, “is that really true?” I often think, “Well, I’ve seen lots of dogs who eat that who haven’t had a problem.” The growing list of toxic foods for pets now includes chocolate, onions, grapes, raisins, and chewing gum containing xylitol (many of the sugar free gums). Although I read these new reports critically, working in emergency, I have now seen all these toxicities first-hand.

Chocolate toxicity has been known to many of us for years. Theobromide, a methylxanthine, is the main toxic component, and causes extremely fast heart rates, tremors, and can lead to seizures. The darker the chocolate, the more theobromide is contained in each ounce and the less the pet has to eat of it to cause problems. White chocolate is actually not toxic at any amount. A 60-pound lab would need to eat 20 ounces of milk chocolate to have moderate to severe signs but only three ounces of dark bakers chocolate. Depending on when the chocolate was ingested, we might recommend inducing vomiting or having us administer activated charcoal. (Activated charcoal binds toxins that are in the stomach or intestinal tract so they can’t be absorbed into the blood stream.) We’ve seen many dogs that presented with agitation and severely elevated heart rates. Most have done well but some needed 24-48 hours in the hospital on IV fluids and medication to decrease the dangerously high heart rates.

Onion toxicity is one I hadn’t seen until a few years ago. Onions and other members of the Allium family (shallots, garlic, and green onions) contain a compound that can weaken red blood cells. The red blood cells break down causing anemia (lack of red blood cells) and hemoglobin (the protein inside red blood cells) to spill into the urine. Dog’s red blood cells have less antioxidants than people’s making their cells more prone to damage. Cats are even more susceptible to red blood cell damage. Ingestion of 5g/kg of onion in cats or 15-30 g/kg in dogs can lead to clinically important hemolysis. Damage consistently happens in dogs who ingest more than 0.5% of their body weight in onions at one time. A few years ago, an English setter was referred to us for inappropriate urination and red colored urine. It turns out he had eaten three cups of onions the day before – 1.5% of his body weight! The red color was hemoglobin in his urine. He became very anemic four days after he ate the onions and needed a transfusion. To complicate matters in his case, he also had a bacterial urinary infection. The combination of the hemoglobin going through his kidneys and the infection, despite antibiotics and IV fluids, led to acute kidney shut down. After 10 days of hospitalization, antibiotics, and IV fluids, he is doing well at home.

Grape and raisin toxicity was first reported by the National Animal Poison Center in 2001. At that time, they knew of 10 reported cases of acute kidney failure with ingestion of quantities varying from 0.2 oz/lb to 4.4 oz/lb. A retrospective study was published in 2005 in the Journal of Veterinary Internal Medicine involving 43 cases. Of the 43 cases, 20 died or were euthanized due to a poor prognosis. Unfortunately, it is still not known why some dogs, but not all dogs, develop acute kidney failure from ingestion of these foods. Pesticides, fungus and heavy metal contamination have been ruled out as causes and it appears that the toxic principle is in the flesh and not in the seed. Last year, we treated a dog who developed acute kidney shutdown after eating grapes off a vine at a friend’s house. The dog survived and is now doing well but was hospitalized for almost two weeks and required subcutaneous fluids for many weeks afterward. We do recommend inducing vomiting, activated charcoal and IV fluid diuresis with any grape ingestion over 0.7 oz/kg or raisin ingestions over 0.1oz/kg. Induction of vomiting is recommended up to eight hours after ingestion in these cases as in many of the cases reported to National Animal Poison Center, raisins were still found in the vomit at this point.

Xylitol is a sugar substitute that is good for people on a low carbohydrate diet, those with diabetes or those watching calories. It is found in sugar free gum, some toothpastes (it can prevent oral bacteria from producing acids that damage tooth surfaces), and can be bought as a powder for cooking. Although the lethal dose is >130 g/day in people and greater than 20g/kg in mice, the metabolism is different in dogs. It appears that doses greater than 0.1g/kg can lead to hypoglycemia 30 minutes to 12 hours after ingestion. This is because in dogs, but not in people, xylitol causes a dose-related rapid, severe insulin release. In addition, acute liver failure and bleeding problems has been reported in eight dogs after eating xylitol containing products. Most of the dogs presented with vomiting and lethargy nine to 72 hours after xylitol exposure. The reason for the liver failure is currently unknown. National Animal Poison Center does recommend vomiting induction, IV fluids, and careful monitoring of blood glucose and liver enzymes.

The NAPCC is a fantastic resource and we recommend that their phone number be easily accessible in your household. The Washington Poison Center now also has a veterinary toxicologist on staff and is also very helpful especially in cases of household chemicals or product exposure. In addition, our emergency doctors are very knowledgeable about toxicities and are always happy to answer questions at any time of day or night. (NAPCC, 888-426-4435 and Washington Poison Center, 800-222-1222)

Could Pollen Kill My Cat?

By Beth Davidow, DVM DACVECC 

Last week, we received a phone call from an owner who saw her cat walking around with pollen on its face. She had just received a bouquet of lilies, had put them up high, but then saw her cat in that area. A quick internet search revealed that lilies were toxic and she wanted to know what to do.

We informed her to come in right away. Although sometimes the internet has stories that scare you unnecessarily, the danger of lilies to cats is not scary or loud enough. In a recent study of 48 households with cats exposed to lilies, only 27% of owners knew that lilies were toxic. In those cases, the owners thought the lilies were out of the way enough but the cats reached them anyway.

Asiatic lilies, the big beautiful ones that are especially common around Easter, are incredibly toxic to cats. The lilies that are toxic are from the Lilium or Hemerocallus species. Common names include Stargazer, Easter, Tiger lily, and day lilies. We don’t know what the toxic compound is but we do know that it concentrates in the pollen and that only a small amount is enough to cause acute kidney shutdown. Lily of the valley is not a true lily and therefore does not cause acute renal failure. It has cardiac glycosides (similar to digitalis) that can cause other symptoms. Peace and calla lilies contain calcium oxalate crystals and usually cause immediate oral and GI irritation and vomiting but do not cause kidney failure.

As with many toxicities, signs don’t happen instantly. With lilies, some vomiting may be seen within a few hours. Cats then often seen to be OK or a little lethargic but then become very sick again in 24-72 hours. Elevations in renal values can be detected on blood work as early as 12 hours after ingestion. If treatment is delayed for 24-48 hours, the insult to the kidneys may be irreversible.

If you suspect your cat has chewed on a lily, it is best to err on the side of caution and seek treatment. Your veterinarian may induce vomiting (if the cat has not already vomited parts of the plant) and follow up with a slurry of activated charcoal to bind up any remaining toxins in the GI tract. Intravenous fluids are recommended for at least 48 hours.  Baseline blood work is obtained and renal values are monitored every 24 hours.  If caught early and treated aggressively, the prognosis is good and no lasting damage occurs.  In the study mentioned above looking at cats exposed to lilies, 90% did well with appropriate treatment but 10% did have renal damage. 

In our recent phone call, we recommended aggressive treatment, the cat was hospitalized on IV fluids for 48 hours, and did fine with no long term problems.

So this spring, tell your friends, tell your colleagues that yes, some pollen could kill your cat.

For more information on toxic plants, see http://www.aspca.org/.

References:

Slater MR, Gwaltney-Brant S.  Exposure Circumstances and Outcomes of 48 Households with 57 Cats Exposed to Toxic Lily Species.  JAAHA 2011; 47: 386.

Marijuana Toxicity in Pets

By Dr. Beth Guerra

At the emergency clinic, we commonly treat pets that have gotten into household medications, even those considered to be hidden or out of reach. For example, we often see a range of medication ingestions, from vitamin supplements to heart medications.

However, in the last few months, we are seeing a greater number of pets who have gotten into owners medicinal or recreational marijuana. The active compound, THC, interacts with neurotransmitters in the brain and can cause a variety of symptoms. The amount of THC varies greatly (i.e., dried product vs. oil), as does a pet’s individual response to the drug. According to the ASPCA Poison Control Database, research has shown that ingestion of 3-9g/kg of body weight can cause symptoms. Death from ingestion can occur, but is rare. A majority of cases (97%) are dogs.

Pets that have ingested marijuana can exhibit a variety of symptoms. The most common are walking off balance (ataxia), not reacting normally, acting depressed, hypersalivating, and dribbling urine. Pets may also have dilated pupils, can seizure, and may have a fast heart rate. Occasionally, agitation may occur. If the product has been baked into goods containing chocolate, the pet must be monitored and treated for those symptoms as well. Treatment of marijuana toxicity is focused on decontamination and supportive care. Often, vomiting is induced, especially within several hours of suspected ingestion. Several doses of activated charcoal may be given to prevent further absorption from the GI tract. In severely affected animals (i.e., overly sedate), IV fluid support and hospitalization for monitoring may be recommended until the pet is more responsive. Symptoms usually resolve within 24 hours with no lasting effects.

Pet owners are often reluctant to admit that exposure to marijuana is a possibility. However, it is crucial to inform your veterinarian of any possible exposure to this or other drugs. We are not required to contact the authorities about drug ingestions and only use the information to best treat your pet. Signs of marijuana toxicity can be similar to other types of issues. If we don’t know about the exposure, we may need to run tests to rule out other diseases. If we know of the exposure, we can often provide supportive care and be fairly sure of a good outcome.