Diagnostic tests are needed to recognize rodenticide poisoning and exclude other diseases. The tests necessary for diagnosis vary according to the type ingested. In some cases, there is no definitive test that can be performed to confirm the diagnosis.
Often, the owner of a poisoned pet can produce evidence that a pet has chewed or consumed a box of rodenticide. Regardless of these circumstances, testing is often necessary to monitor a patient's progress as they are treated for poisoning. Tests vary with the toxin. Tests for the different toxins may include:Anticoagulant rodenticide exposure A history of exposure is the single most important diagnostic tool. If the owner of a poisoned pet witnesses the ingestion or can produce the remnants of containers or labels, this greatly limits the need to look for other causes.
Your veterinarian should complete a thorough physical examination to look for evidence of bleeding such as swollen joints, hematomas (swellings under the skin containing blood) or pale gums indicating anemia (low red blood cell count).
A complete blood count (CBC) is obtained to look at the characteristics of the red blood cells. The CBC helps determine whether the loss of red blood cells has been sudden (more consistent with poisoning) or chronic.
A serum chemistry profile is helpful to eliminate kidney or liver problems, both of which can cause anemia or bleeding problems.
A platelet count is important to rule out bleeding from low platelet levels, which can be caused by other diseases.
A reticulocyte count determines whether the animal's body is trying to regenerate red blood cells that have been lost.
A PIVKA (Proteins Induced by Vitamin K Absence or Antagonists) test is a blood test that can be collected by your veterinarian and sent to a lab to determine if bleeding is due to exposure to anticoagulant rodenticides. Because this test is performed in a lab outside of your veterinarian's hospital, the results may take several days.
Clotting tests such as an activated clotting time (ACT), prothrombin time (PT) and activated partial thromboplastin time (APTT) are used to determine if anemia and/or bleeding are due to the inability of the animal to clot its blood. These values are greatly prolonged in anticoagulant rodenticide poisoning. As the pet is treated, your veterinarian will likely repeat these blood tests to confirm that they normalize.
Bromethalin, cholecalciferol, strychnine and zinc phosphide-containing rodenticides
A history of exposure, observation of symptoms associated with these types of rodenticide poisoning and a thorough physical exam are the best diagnostic tools.
A CBC is usually done to evaluate for infection or inflammation as potential causes for the pet's symptoms.
A serum biochemistry profile helps to evaluate the kidneys and liver for evidence of failure. Abnormalities in electrolytes such as sodium will also be detected with this test.
Examination of stomach contents or vomit may raise the suspicion of poisoning or identify the remnants of the poison ingested and a pet owner can be sent home to look for evidence of a chewed package to confirm the diagnosis.
Depending on the amount of rodenticide ingested, type ingested and the length of time elapsed since ingestion treatment varies. Some patients may be treated on an outpatient basis while others require hospitalization. Treatments for rodenticide poisoning may include one or more of the following:
Standard treatment for poisoning (if within 4 to 6 hours of ingestion) includes:
Administering either apomorphine (a powder placed in the corner of the eye) or hydrogen peroxide orally to induce vomiting. Induced vomiting removes undigested poison from the stomach.
Activated charcoal to absorb any poison remaining in your pet's stomach or intestinal tract after induced vomiting or gastric lavage. A cathartic is often administered after the charcoal to help speed movement through the digestive tract and elimination. Activated charcoal is administered via a stomach tube or is syringe fed to the animal.
Pumping the stomach. If your pet cannot be induced to vomit, the dog's stomach can be pumped. During this procedure, a large tube is passed through the mouth to the stomach. Water is pumped into the stomach and then drained, removing any stomach contents. This procedure requires heavy sedation.
Administering intravenous fluids to correct dehydration from vomiting or diarrhea and to aid in the removal of some poisons and protect the kidneys from damage.
In addition to the standard treatment for poisoning, each type of rodenticide requires different treatment approaches because each poison affects animals differently.
For anticoagulant rodenticide, these may include:
Additional therapy may not be required if the poison is removed from the stomach.
Administration of Vitamin K is necessary to replace the Vitamin K, which cannot be made by the body due to interference by the rodenticide. Vitamin K therapy is initiated in hospital and is then continued at home for a total of 3 to 5 weeks.
A blood transfusion will be administered if the pet has lost a large amount of blood, due to bleeding, and is anemic.
A plasma transfusion often is given to replace missing clotting factors when the pet's bleeding times are greatly prolonged. This helps to prevent additional bleeding while waiting for the Vitamin K to work (usually 24 to 36 hours).
For bromethalin containing rodenticides, treatment may include:
Drugs such as mannitol and/or steroids are used in an attempt to control cerebral edema (swelling of the brain) that occurs with this type of poisoning. These drugs often require repeated intravenous administration.
Anticonvulsant drugs such as diazepam (Valium®), phenobarbital and pentobarbital are used to control seizures and severe muscle tremors, as well as to promote muscle relaxation.
For cholecalciferol containing rodenticides, these may include:
Drugs such as furosemide, steroids and calcitonin may be used in conjunction with intravenous fluids to reduce serum calcium levels. Furosemide and steroids are used predominantly. Calcitonin is used when the other drugs are not sufficient to control calcium levels alone.
Furosemide and dopamine are administered to promote blood flow to the kidneys and to increase urine output during kidney failure.
For strychnine, these may include:
Muscle relaxants are necessary to allow the animal to relax rigid muscles and legs.
Anticonvulsants such as Valium®, phenobarbital and pentobarbital are used to reduce or prevent seizures that accompany strychnine poisoning.
For zinc phosphide containing rodenticides, these may include:
There is no definitive treatment for zinc phosphide containing rodenticides; therefore treatment is directed at removing the poison from the digestive tract and general in-hospital supportive care.