Zinc Toxicity

Today’s path rounds are on 𝐳𝐢𝐧𝐜 𝐭𝐨𝐱𝐢𝐜𝐢𝐭𝐲!

𝐖𝐡𝐚𝐭 𝐢𝐬 𝐢𝐭?
𝐙𝐢𝐧𝐜 is a trace mineral that has many different roles in the body, including growth, wound healing, vision and immunity. However, too much of a good thing is a bad thing!

𝐖𝐡𝐨 𝐠𝐞𝐭𝐬 𝐢𝐭?
We most commonly see this in dogs, cats and birds, however any species can be affected.

𝐖𝐡𝐚𝐭 𝐜𝐚𝐮𝐬𝐞𝐬 𝐢𝐭?
Usually zinc toxicity occurs from animals eating metal objects made of zinc. One of the most common zinc-containing objects are US pennies made after 1982! Although we think of them as being made of copper, they are actually a zinc core with a thin layer of copper over top. When the pennies are eaten, the acidity of the stomach degrades the zinc, allowing it to be absorbed into the body. This results in zinc toxicity!

𝐖𝐡𝐲 𝐢𝐬 𝐭𝐡𝐢𝐬 𝐚 𝐩𝐫𝐨𝐛𝐥𝐞𝐦?
The major problem with zinc is 𝐡𝐞𝐦𝐨𝐥𝐲𝐬𝐢𝐬, or destruction of red blood cells. This results in 𝐚𝐧𝐞𝐦𝐢𝐚 (low red blood cell count) and can make proper oxygenation of the tissues difficult. Zinc can also cause liver, kidney and pancreatic damage, although the mechanism behind this is unknown. Animals with zinc toxicity will show vomiting and diarrhea, which may progress to 𝐦𝐞𝐥𝐞𝐧𝐚 (blood in the feces). When anemia occurs, animals may develop 𝐭𝐚𝐜𝐡𝐲𝐜𝐚𝐫𝐝𝐢𝐚 (rapid heart rate), 𝐢𝐜𝐭𝐞𝐫𝐮𝐬 (yellowing of the tissue) and liver or kidney failure. In some cases, animals may die if not treated.

𝐇𝐨𝐰 𝐢𝐬 𝐢𝐭 𝐝𝐢𝐚𝐠𝐧𝐨𝐬𝐞𝐝?
Diagnosis is usually based on bloodwork, which will show the red blood cell changes associated with zinc toxicity. Taking X-rays can also be helpful, as the veterinarian is easily able to identify metallic objects within the stomach. If further confirmation of the diagnosis is needed, the total level of zinc in the blood can be measured.

𝐇𝐨𝐰 𝐢𝐬 𝐢𝐭 𝐭𝐫𝐞𝐚𝐭𝐞𝐝?
Treatment typically involves surgical removal of the object from the intestinal tract, to remove the source of zinc. Often animals will need a blood transfusion or other medical interventions to treat the toxicity itself. Thankfully, most animals will recover with appropriate treatment.