What is bromethalin rodenticide poisoning?
Bromethalin is one of the most common types of rodenticides currently on the market. It is found in several forms, including hard blocks, soft baits, pellets, worms/grubs, and meal/grain. Cats are commonly poisoned when they find loose bait placed for rodent control. Relay toxicity, where poisoning occurs due to ingesting rodents that died from bromethalin, has been anecdotally reported in cats.
Once ingested, bromethalin is rapidly absorbed from the gastrointestinal (GI) tract and metabolized in the liver to its more toxic form. The primary target for bromethalin and its metabolite is the central nervous system (CNS). It causes depletion of energy in the CNS, ultimately resulting in swelling of various areas of the CNS, including the brain (cerebral edema), leading to severe neurologic signs. Clinical signs can develop as soon as two hours after exposure and as long as 24-48 hours after exposure.
What are the clinical signs of bromethalin poisoning?
Cats are more sensitive to bromethalin and develop toxicity at lower doses than dogs. Also, unlike dogs, cats develop common signs at any toxic dose. Clinical signs include depressed mental activity, anorexia, vomiting, ataxia, decreased intestinal motility, and pelvic limb weakness that progresses to paralysis. As the poisoning progresses, tremors, seizures, abnormal body positioning, and coma develops.
How is bromethalin poisoning treated?
There is no antidote for bromethalin, so early decontamination is extremely important. If a cat ingests a toxic dose of bromethalin, prompt induction of vomiting by a veterinarian can be lifesaving. There are no safe ways to induce vomiting in cats at home. After vomiting has occurred, multiple doses of medical-grade activated charcoal are administered and intravenous (IV) fluids are delivered to maintain hydration. Close electrolyte monitoring is important to watch for elevated sodium levels.
If clinical signs develop, mannitol is started to decrease cerebral edema. At the same time, clinical signs are treated with anticonvulsants, muscle relaxants, antiemetics, and GI prokinetics, as needed.
What is the prognosis for bromethalin toxicosis?
Unfortunately, prognosis is poor to grave if severe clinical signs develop such as seizures, paralysis, or coma. Patients with milder clinical signs may recover after several weeks but may have permanent neurologic damage. If clinical signs can be appropriately managed but there is no improvement after a week, prognosis is poor.
If you suspect or witnessed your pet ingesting rodenticide, call Pet Poison Helpline, a 24/7 animal poison control center, at 1-855-764-7661 and take your pet to a veterinarian for treatment.
Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com.