We had an all too-common occurrence in our clinic a few years ago. A client, Christina, brought her little mix, Boogs, into the clinic one evening. She was concerned because Boogs was seeping blood from a small cut on her leg. Nothing seemed to stop the seepage. We took a history and questioned the owner. It turned out that Boogs had run off that morning and when she came back Christina noticed the cut, but did not worry about it since it seemed so small. She washed it and wrapped it up to keep it clean then went off to work. When she came home she noticed that there was an 8 inch diameter spot of blood that had soaked into Boogs' bed. Although the dog was acting fine, Christina decided to bring her in.
When questioned further, it turned out that Christina was living in a friend's basement and the friend had mice. We did not know for sure, but suspected that the dog had ingested some of the rodenticide that had been set out for the mice.
Used to kill mice, rats, and other rodents, ingredients of concern in many rodenticides are anticoagulants, which slow the clotting of the blood. When ingested, these anticoagulants concentrate in the liver, where they interfere with the normal synthesis of clotting factors by the liver. Four common active ingredients in anticoagulant rodenticides are: Dicoumarol, Diphacinone, Brodifacoum, and Bromadiolone. We found out that the particular rodenticide Boogs may have ingested contained dicoumarol, also known as Warfarin.
Even though we merely suspected the exposure, we immediately treated Boogs with fluids and an injection of Vitamin K because of her symptoms and history. We treat more cases of rodenticide poisoning than all other toxins combined. Rodenticides are tasty in order to attract rodents, but that makes them attractive to our pets as well.
Make sure to read rodenticide packages thoroughly if you have pets in your house. If you suspect your pet has eaten any rodenticide, have the package with you when you call your veterinarian or poison control center. Some rodenticides, such as dicoumarol, are active in the body for a short period of time. Others persist for 4-6 weeks which means treatment must be extended. That is why it is important for your veterinarian to know exactly what rodenticide your pet may have ingested. Veterinarians can use special blood tests to determine the level of clotting factors in the blood. These tests are useful in the diagnosis and the monitoring of treatment in rodenticide poisonings. Treatment must continue until the clotting factors have returned to normal levels.
Signs of rodenticide toxicity often go unrecognized. Symptoms of rodenticide poisoning often do not show up for several days (and may include internal bleeding), so many owners are not aware that their pet has been exposed. Internal bleeding may go unnoticed even to the veterinarian. The most common sign that owners notice is bloody saliva in the water bowl. Luckily Christina brought Boogs into us the evening she started showing signs. If Boogs had continued to bleed, the outcome would not have been so good.
We watched Boogs overnight and sent her home the next day with a week's worth of oral Vitamin K which brought the level of her clotting factors back to normal. Boogs is still going strong and the homeowner switched to mouse traps.