I love this time of year.  The air has a crisp to it, the leaves are blowing, and the temperature is dropping.  As I start to prepare for winter, I often have a problem with small rodents trying to make their own winter homes in my garage and shed.  Most people just put out some rat/mouse pellets or a block in a bait box and call it a day.  However, did you know that these baits are toxic to dogs and can cause a wide range of issues from tremors, seizures, internal bleeding, to even death?  It is very important to seek veterinary attention as soon as possible if you believe your pet ingested rat/mouse bait.  There are 3 main types of rat/mouse baits and each have different treatments and prognoses.

ANTICOAGULANT

  • These have been the traditional products.  They prevent blood from clotting which leads to internal bleeding.  It is very important to know that these rodenticides do not produce signs of poisoning for SEVERAL DAYS UP TO AT LEAST A WEEK.   So if you think your pet got into rat bait the night or even the day before, it is still important to go to your veterinarian.
  • How does it do this? Anticoagulant rodenticides prevent vitamin K from working properly in the body.  This vitamin is important in activating clotting factors. Think of vitamin K as the gatekeeper.  Without something to open the gate to the rest of the body, the clotting factors cannot circulate.  Without these clotting factors, the body can no longer form clots and uncontrollably hemorrhages.
  • What should I look for? The first clinical signs are often associated with the respiratory system, such as coughing, difficulty breathing, rapid breathing, or exercise intolerance.  Other signs you may see include joint swelling, collapse, swellings under the skin, or bleeding from the nose, mouth, rectum.
  • How is it diagnosed and treated? Anticoagulant rodenticide toxicity is diagnosed based on history of exposure, clinical signs, bloodwork (i.e. clotting times, CBC), and radiographs.  If your pet just ingested the toxin, your veterinarian will induce vomiting then give activated charcoal.  They will also prescribe high doses of Vitamin K.  If your pet is already showing signs, hospitalization will be recommended with support care and plasma transfusion(s).  Your pet will be on Vitamin K for at least 4 weeks and will require recheck bloodwork with your veterinarian to make sure he/she has been taking the Vitamin K for an adequate amount of time.  It is also that you keep your pet quiet for this month since even the most mild injuries can lead to significant bleeding.

BROMETHALIN

  • Due to an EPA requirement to phase out the anticoagulant rodenticides, bromethalin is now the most common rodenticide available for purchase.  This is unfortunate because unlike anticoagulant rodenticides, bromethalin has NO ANTIDOTE. If your pet starts showing signs, all we can do is support him/her until the toxin has run its course.  You typically start to see signs about 4 hours after ingestion and the toxin can stay in the system for a long time, causing extensive damage.
  • How does it work? Bromethalin causes the brain to not be able to utilize oxygen and therefore the brain swells. This causes neurologic abnormalities.
  • What should I look for? Look for lethargy, weakness, incoordination, tremors, seizures, paralysis and eventually death.
  • How do you diagnose and treat it? Diagnosis is based on clinical signs and history of exposure.  There is no test to confirm toxicity.  If a patient has just ingested the toxin, your veterinarian will induce vomiting and prescribe several doses of activated charcoal depending on how much he/she got into and how long ago it was.  If your pet is already starting to show signs, your veterinarian will treat you pet symptomatically with anticonvulsants, muscle relaxers, sedatives, diuretics, and oxygen therapy.  Your pet may also need a feeding tube for nutritional support.   Your pet may have permanent neurologic damage depending on the dose.

CHOLECALCIFEROL

  • How does it do this? Cholecalciferol (Vitamin D3) increases intestinal absorption of calcium, stimulates bone resorption, and enhances renal tubular re-absorption of calcium.  This leads to severe hypercalcemia which could lead to acute renal failure, cardiovascular abnormalities, and tissue mineralization.
  • What should I look for? Signs typically do not show up for 18-36 hours after ingestion.  You may typically see vomiting, diarrhea, inappetance, depression, increased thirst and urination, or cardiac abnormalities.
  • How is it diagnosed and treated? Cholecalciferol toxicosis is diagnosed based on bloodwork and exposure history.  It is important to go to your veterinarian as soon as possible if you think your pet ate rat bait.  Multiple days of hospitalization with intravascular fluids, recheck bloodwork, and medications to help reduce calcium will most likely be recommended.