Rat and mouse poisoning occurs when the cat either directly ingests rat poison or indirectly ingests it after catching and consuming a rodent who has itself ingested poison. Many rat and mouse poisons contain anticoagulants which inhibit the coagulation of blood. Internal bleeding occurs due to the poison which blocks the body's production of clotting factors.
How does internal bleeding occur with rat poisoning?
Blood vessels are tubes which transport blood around the body, they are lined with a thin layer of specialised cells known as endothelial cells. These cells help the blood travel easily along the blood vessels. If the blood vessel breaks, three mechanisms occur to slow and stop the loss of blood.
- Vasoconstriction: Small muscles in the blood vessel wall constrict which reduces the amount of blood flow, reducing blood loss.
- Primary hemostasis: Platelets are circulating cells are activated, clumping together and binding to the site on the damaged blood vessel, to form a plug.
- Secondary hemostasis (also known as coagulation cascade): Proteins known as coagulation factors are manufactured by the liver. A complex set of chemical reactions occurs involving coagulation factors, converting factor 1 (fibrinogen) into fibrin, long thin strands which entangle the platelets.
Rat poison depletes the body of Vitamin K which is necessary for the formation of certain blood clotting factors.
Two types of rat poison contain anticoagulants.
First generation rat poisons have a shorter half-life, which is the time it takes for the poison to decrease by half. The active ingredient in first generation rat poisons is Warfarin. Poisoning occurs after several repeated exposures.
Second generation rat poisons are considerably more potent and. The active ingredients in second-generation rat poisons are usually bromadiolone or brodifacoum. A single dose is enough to kill a cat.
What are the symptoms of rat poisoning in cats?
The poisons have no effect on clotting factors already in circulation, so there will be a lag of 1-3 days before these clotting factors run out (and are not replaced) and symptoms occur.
- Bleeding from the anus, mouth, gums and nose.
- Pale gums.
- Blood in vomit, urine and/or feces.
- Shortness of breath caused by bleeding into the chest.
- Bruising under the skin due to bleeding under the skin.
Not all cats who have ingested rat poison will display symptoms. If you believe your cat has been exposed to rat poison but still looks well, you should still seek veterinary attention.
How is rat poisoning diagnosed?
A history of exposure to rat poison, if possible. Bleeding from several places will also suggest to your veterinarian there is a blood clotting problem.
Your veterinarian may wish to perform some tests, which include blood tests to determine blood clotting time ACT test, PT test, and APTT test.
How is rat poisoning treated?
If you suspect your cat has ingested rat poison, immediate veterinary attention must be sought. If possible, bring along the packaging so that your veterinarian can see exactly which poison has been consumed.
Treatment will include:
- If ingestion has occurred recently, then your veterinarian will induce vomiting.
- Activated charcoal will be administered to absorb the toxin that is still in the intestines.
- Pumping of the stomach contents.
- Vitamin K injection.
- If bleeding is severe, your cat may require a blood transfusion.
- Once your cat has been stabilised, he will be sent home with an oral dose of Vitamin K that will be required for 30-45 days.