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Iron Toxicity in Dogs and Cats

Ingestion of common household items can cause iron toxicity in pets

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Handwarmers / PriceGrabber

Handwarmers

PriceGrabber

Iron Poisoning

Iron poisoning usually occurs when a pet (usually a dog) eats ionizable iron-containing items commonly found around the house. This type of poisoning affects the cardiovascular, metabolic, liver, nervous and gastrointestinal systems. Animals are unable to excrete excess iron. Left untreated, this may be fatal.

Learn what signs are seen with iron toxicosis, and if your pet is suspected of ingesting iron-containing compounds, please seek veterinary care immediately.

Sources of Iron Poisoning

Iron toxicosis in pets is most often seen after eating large quantities of vitamins and mineral supplements especially iron-heavy pre-natal vitamins. These tablets may be sugar-coated, making them attractive to dogs and cats. Other possibilities include disposable hand warmers (pictured above) and iron-fortified fertilizers.

Metallic iron, iron-containing alloys, and iron oxide (rust) are not readily ionizable (bioavailable), and therefore not toxic.

Toxic Doses of Iron

From Ahna Brutlag DVM and Justine A. Lee DVM DACVEC, staff veterinarians at Pet Poison Helpline and authors of the Five-Minute Veterinary Consult: Small Animal Toxicology reference guide, here are the amounts of iron that are toxic to dogs.
Oral toxic dose (dogs)
● <20 mg/kg of ionizable iron is less likely to cause poisoning in most pets. However, certain animals, such as those with underlying gastrointestinal or kidney disease, may be more at risk.
● 20-60 mg/kg of ionizable iron can result in clinical signs.
● >60 mg/kg of ionizable iron can result in serious clinical disease.

Injectable iron is more toxic due to much greater bioavailability.

Clinical Signs of Iron Toxicity

Because iron poisoning affects the cardiovascular, metabolic, liver, nervous and gastrointestinal systems, many signs are seen. Most often, the gastrointestinal signs present first, since this is the usual route of toxicosis (animals eating iron-containing items).
● Vomiting
● Diarrhea
● Lethargy
● Gastrointestinal hemorrhage
● Abdominal pain
● Shock
● Tremors
Between 6 and 24 hours post-ingestion, some animals may appear to recover, only to get worse. Some animals may see gastrointestinal obstruction as late as 6 weeks post-ingestion due to strictures forming after the massive mucosal injury resulting from the cellular damage from iron.

Treatment for Iron Toxicity

Time is critical. If you suspect that your pet has eaten iron-containing items, please seek veterinary care immediately.

Activated charcoal should not be used - it does not bind iron to deactivate the toxin. If early, and the patient is asymptomatic (just consumed the items), vomiting is induced to remove the pills or items from the stomach. Caution is advised though - if gastric damage (i.e. bloody vomit) is present, vomiting is not indicated.

Your veterinarian may need to perform gastric lavage (flushing) or surgery to remove the iron sources. Lavage is not indicated if the patient has bloody vomiting. This may increase risk of gastric perforation.

Additional supportive care - IV fluids, gastro-protective medications, anti-vomiting medications and chelation (binding) agents as needed.

Prognosis for Iron Toxicity

If patients do not develop clinical signs in the first 8 hours, the prognosis is good.

In patients that are treated prior to development of clinical signs, they need to be watched closely for the first 8 hours.

For patients with clinical signs of toxicity, the prognosis is guarded until the various treatment and drug therapies can bring down the blood levels of iron. The prognosis is based on the severity of clinical signs and watching for development of post-exposure problems such as gastrointestinal stricture, mentioned above.

Follow Up Care

Depending on the clinical signs seen, food intake and activity levels may be limited. Your veterinarian will be able to guide you on case-specific follow up care.

Thank you to Ahna Brutlag DVM and Justine A. Lee DVM DACVECC of Pet Poison Helpline for assistance with this article.

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