Mind over metal: Staying wary of metal-related toxicities for pets

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Pets encounter a variety of everyday risks, from outdoor threats like animals or parasites to physical dangers like vehicles or sharp objects and household toxins like plants or cleaners. However, many owners may underestimate the invisible dangers—such as poisonous metals—that their pets could also come across in their daily lives.

While metal poisoning is not highly common in small animals, there are several potential intoxications that can require emergency care and sometimes intensive intervention.

Dr. Christine Rutter, a clinical associate professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, discusses the health risks associated with different metals and how owners can keep their pets safe.

Zinc intoxication

According to Rutter, the intoxication most commonly seen in the emergency department at Texas A&M is from zinc, usually from ingesting a penny.

"Pennies minted after 1982 are copper-coated zinc disks," Rutter said. "Once ingested, the acids in the GI tract erode the copper and expose the zinc, which directly irritates the esophagus or stomach wall and is absorbed into the GI tract."

Many wire crates are made of zinc, so pets that tend to chew on crate bars may also be in danger of zinc toxicity; the same worry surrounds pets licking diaper creams and zinc-based sunscreens.

Clinical signs of intoxication can vary and may include:

• Lethargy
• Weakness
• Pale mucous membranes (gums)
• Yellowing of the skin
• Anorexia
• Collapsing

Rutter notes that some pets may not show clinical symptoms until they are severely affected.

The GI irritation caused by zinc can be severe and sometimes even requires surgical intervention. Once a veterinarian identifies a penny or other ingested metal with X-rays, they can remove the fragment with an endoscope or surgery.

"The zinc toxicity itself can destabilize red blood cell membranes and cause them to rupture, meaning that pets may need a blood transfusion," Rutter said. "While the prognosis for zinc toxicity is usually good, pets can be very sick and require a lot of care to get them back to health."

Rutter suggests avoiding the use of diaper creams and zinc-based sunscreens on small animals, as pets may lick it off.

"The level of concern depends on the product, but it is in the pet's best interest to avoid the risk altogether," she said.

Lead intoxication

When a pet has low red blood cell counts and a chronic course of illness, lead poisoning is one of the things veterinarians consider.

Pets are usually exposed to lead by ingesting paint chips; parts of painted objects, like toys; or objects made of lead, like fishing lures or ammunition fragments.

"Pets typically have to ingest lead for it to become toxic, meaning that pets are not at risk for lead intoxication due to retained lead pellets, bullet fragments, or shotgun pellets remaining in the body," Rutter said. "When a pet is taken to the vet with a gunshot wound, we don't go in surgically to remove those projectiles unless we assess that they are causing prolonged pain or other injury."

When veterinarians suspect lead intoxication, they will perform a complete blood count and blood film evaluation.

"Metal fragments are usually visible on X-rays, but the absence of fragments doesn't rule out intoxication," Rutter said. "Treatment is focused on removing the source of intoxication, though other medical therapies—like a blood transfusion—may be necessary."

Whether bringing your furry companion into a new home, a vacation rental, or an afternoon at a friend's house, owners should be aware of the lead threats associated with a dated space.

"Leaded paint was banned in the U.S. in 1978, but there are still plenty of older homes and antique toys with lead paint present under newer paint layers," Rutter said.

Home testing kits for lead are available for owners who want to test painted surfaces, paint chips, and any antique metal objects.

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Copper intoxication

Copper intoxication can occur when an animal ingests copper-containing materials—such as antifouling marine paint or a high-copper diet.

"Foods certified by the Association of American Feed Control Officials (AAFCO) are fine," Rutter said. "High copper content in a diet is uncommon unless dogs eat food intended for other species."

Another explanation for intoxication is when an animal experiences a genetic error of copper metabolism.

"Some breeds of dogs—such as Labrador retrievers, West Highland white terriers, American cocker spaniels, and Doberman pinschers—are genetically predisposed to copper storage disorders," Rutter said.

In affected dogs, copper builds up in the body and causes inflammation and red blood cell destruction with signs of intoxication ranging from vague to severe.

"Blood testing, such as a complete blood count and blood chemistry, may suggest liver dysfunction or red blood cell changes," Rutter said. "Definitive diagnosis typically requires a tissue biopsy. Most dogs without exposure or genetic risk are not in danger of copper toxicity, but we do look for it in some breeds and dogs with chronic hepatitis."

Guarding against invisible dangers

Although metal intoxications are rare in small animals, owners should still be mindful of what their pets have access to and be prepared in case of emergency.

"Prevention is about limiting exposure and, when possible, entirely avoiding pets' encounters with these metals," Rutter said.

By prioritizing awareness regarding potential household threats and consulting a veterinarian if your pet comes in contact with a potentially toxic metal item, owners can ensure their pets continue enjoying a lifestyle free from metal mishaps.

Key concepts

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Provided by Texas A&M University