by Jennifer Chaitman, VMD, ACVIM (Internal Medicine)
People wonder if their pet has been poisoned. This is suspected if a pet is suddenly sick, yet hard to pin down if the pet is not seen ingesting a toxic substance.
There are many environmental toxins that are dangerous to your pet including insecticides, rat poison, antifreeze, fungi, metals, and plants. Medications and foods safe for humans can also be poisonous to dogs and cats.
Insecticides are commonly used and are toxic if inhaled or ingested. They work by inhibiting an enzyme in the nervous system which results in overstimulation. Major signs in pets include salivation, tearing, urination, and diarrhea. You may notice that small pupils, muscle tremors, or trouble breathing. If you think your pet has such a toxicity, bring the product label if possible to your veterinarian.
Rodenticides made of coumarin compounds or warfarin, and second generation rodenticides such as bromadiolone and brodifacoum inhibit blood clotting. If ingested, your pet can become anemic from internal blood loss. You would first notice weakness, possible bruising and pale gums. Signs of coumarin toxicity can be seen 3-5 days after exposure and last for 4-7 days; signs of brodifacoum (D-con) show up 4-7 days later and last for 2-4 weeks. You would notice an elevated respiratory rate, pale gums, and sometimes a swollen belly or limb. Your veterinarian can perform a blood clotting test and a PIVKA test (tests for a deficiency of vitamin-K dependent clotting factors) to make the diagnosis. Treatment consists of plasma and or blood cell transfusions if necessary, vitamin K supplementation and supportive care.
Metals such as zinc, iron and lead can be toxic. Zinc is found in pennies made after 1983 and some ointments (such as desitin). Ingestion can cause yellow skin, anemia, weakness, vomiting and diarrhea. Your veterinarian can make the diagnosis by finding pennies in the stomach or intestines on x-ray or endoscopy, or from the history of eating a zinc containing substance. In severe cases a chelating agent is given after the zinc source has been removed to stabilize the patient.
A common source of iron toxicity in dogs are iron supplements. Signs are vomiting, diarrhea, dullness and shock. Your veterinarian can make the diagnosis by testing blood iron levels and may then administer desferoxamine with supportive care.
Lead toxicity occurs when pets ingest autoparts, paint, fishing sinkers, pottery glazes, stained glass or lineolum made with lead. Signs are seizures, vomiting and diarrhea. Often the foreign object containing the lead can be seen on an x-ray, and blood lead levels can be performed. Treatment is a chelating agent and supportive care.
Antifreeze made of ethylene glycol is very toxic to dogs. Dogs will drink it from puddles on the ground because of its sweet flavor. Soon after ingestion it will cause depression, vomiting, wobbliness and increased thirst. Seizures may follow. If not treated, it can cause renal failure which is often fatal since ethylene glycol metabolizes to calcium oxalate which precipitates in the kidneys. Your veterinarian may suspect ethylene glycol toxicity if there is acute renal failure, calcium oxalate crystals in the urine, or characteristic changes in the kidneys seen with ultrasound. Treatment consists of medications that inhibit the enzyme alcohol dehydrogenase.
Non-steroidal anti-inflammatory medications can make cats and dogs very sick. One Tylenol can kill a cat. Signs would be a puffy face and blue gums. Dogs are very sensitive to aspirin-type drugs, like plain aspirin and especially naproxen sodium (Aleve), and can develop bleeding ulcers. Signs of ulcers include pale gums, vomiting blood, and dark, tarry stool. Treatment consists of supportive care.
Onions are also toxic, even onion powder and dried onions. It can cause a severe anemia in dogs and cats by damaging red blood cells such that they become weaker than normal and break open. You would notice an elevated respiratory rate and pale gums. If you have just seen your pet eat onions, your veterinarian can induce vomiting before the damage occurs.
Raisins and grapes can cause kidney failure. The mechanism is unknown yet even a few grapes have caused kidney failure in a small dog so it is best to avoid them.
Chocolate is also toxic and results in hyperexcitement, seizures, vomiting, and diarrhea. Dark chocolate is more toxic than milk chocolate because it contains more of the toxic substance theobromine. If caught early it is best to induce vomiting.