Mindy - Rodent Poisoning

By:  Andy Cameron, DVM

Mindy, a two year old spayed female Terrier mix dog came to the emergency clinic  in the evening because of a swelling in her mouth and bleeding from her mouth. Mindy had been acting more timid and hiding throughout the day and had a poor appetite that day. She was acting normal just yesterday and had not suffered any trauma or been exposed to toxins that the owner was aware of.

 Upon examining Mindy, her vital signs were normal and she had saliva with blood coming from her mouth. She had a large swelling that was purple in color under the right side of her tongue. This swelling was also visible under the right side of her jaw.

 A swelling such as this can be caused by an abscess (infection), a salivary mucocele (leakage and accumulation of saliva in tissue under the tongue), bleeding (a hematoma) or cancer.

 A fine needle aspirate (FNA) of the swelling in her mouth showed numerous red blood cells, white blood cells and bacteria. These findings were most consistent with a submandibular (under the chin) abscess.

 However, while Mindy was in the hospital, the location of the needle aspirate continued to drip blood and we noticed that she was bruising very easily from areas where blood was drawn. She was also very weak and pale.

 Further questioning of her owners revealed that Mindy had been in the garage a few days ago and that there was mouse poison in the garage, although the owners did not think that she could get to it or would want to eat it. Rodent poisons such as D-CON contain blood-thinning chemicals similar to coumarin, which interfere with the body’s ability to clot blood. These poisons are made to taste and smell good so that they easily entice mice and rats (and any other animal) to eat them. Animals that ingest such poisons bleed to death, usually internally with no sign that they are bleeding. The initial signs of poisoning are non-specific signs such as weakness, lethargy, loss of appetite, difficulty breathing & pale gum color. It usually takes 2-3 days from the time of ingestion until the animal starts to become sick from the poison.

 Coagulation times (bleeding tests) run on Mindy’s blood were extremely prolonged, a sign of rodenticide intoxication. Mindy was started on high doses of Vitamin K, the antidote for rodenticide. Because of her poor condition & continued bleeding.

Mindy was also given a blood transfusion to replace the clotting proteins damaged by the poison before the Vitamin K antidote would start working. Mindy was also placed on antibiotics for the abscess. The dripping of blood stopped, the swelling subsided and Mindy returned to normal over the next few days. 

Anticoagulant rodenticides (DCON, etc) are one of the most common poisons used and one of the most common accidental poisonings of dogs. Contrary to popular belief, these poisons smell good and are very tasty, making it easy & rewarding for a dog to find and eat. Only a small amount of poison is necessary to cause a poisoning and without treatment death is likely.

Dr. Andy Cameron left the field of architecture and construction in northern New Mexico to attend veterinary school at Colorado State University.  He received his Doctor of Veterinary Medicine degree in 2000.  He spent his first two years of practice in a mixed animal practice in rural Arizona and returned to Santa Fe in 2002 to work at the Eldorado Animal Clinic.  While practicing large and small animal medicine and surgery at Eldorado, he started his own mobile large animal practice, Cameron Veterinary Services in 2008.  In the fall of 2009, he left the Eldorado Animal Clinic and joined the emergency staff at the Santa Fe Veterinary Emergency and Specialty Center.  Dr. Cameron continues to work at his large animal practice and also provides veterinary services to the Wildlife Center in Espanola, NM. When not working, Dr. Cameron enjoys spending time with his two children, hiking, horseback riding & playing fiddle.