Zinc is a metal and an essential trace mineral which is necessary for many functions and is the second most abundant metal in the body after iron. It is found in many types of food such as beef, spinach, oysters, seafood and egg yolks.
Zinc is vital for several bodily functions including maintaining a healthy immune system, fertility (in both males and females), synthesis of DNA, wound healing, kitten growth, cell growth, hair and skin growth as well as being a requirement for the activity of many enzymes within the body.
While a small amount of zinc is a requirement in the cat’s diet, too much can result in toxicity. In cats, this is usually a result of accidental ingestion of zinc, such as some coins (USA pennies minted after 1982, £2 coins, nuts, galvanised metal (including cages), fertilisers, calamine lotion, shampoos and creams containing zinc such as sunscreen or adding supplements to your cat’s diet.
Too much zinc causes digestive problems and early symptoms or low doses may present with the following symptoms:
As poisoning continues, or if a large amount of zinc has been consumed, hemolysis (red blood cell death) occurs, resulting in jaundice, anemia, kidney and liver failure.
Symptoms may include:
- Pale gums
- Red coloured urine
- Jaundice (yellow mucous membranes)
- Increased or decreased urine output
- Increased thirst
Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you, including possible exposure to zinc. He will need to run some diagnostic tests, which may include:
- Complete blood count which may reveal hemolytic anemia.
- Urinalysis to evaluate kidney function.
- A biochemical profile to look for elevated bilirubin, which is a breakdown product of red blood cells and assess kidney function.
- Serum zinc level which will reveal levels greater than 0.7 mcg/ml.
- Abdominal imaging to look for foreign objects such as coins in the gastrointestinal tract.
- Removing the source of poisoning where possible. This may include inducing vomiting, endoscopy or surgery. Once the object has been removed, levels quickly drop over the next few days.
- Chelation therapy. This medication is given via injection or tablet and binds to the zinc, which is then excreted out in the urine.
- Severe cases where hemolysis has occurred may require a blood transfusion.
- Treat kidney failure if it has occurred.
Supportive therapies while your cat recovers are essential, these may include:
- Fluid therapy to treat dehydration and assist the kidneys in flushing out any zinc from the system.
- Medications to treat vomiting.
The outcome depends on the severity of anemia and how much kidney or liver failure has occurred.
Avoiding zinc poisoning in cats:
Keep coins and zinc objects out of reach of cats.
Don’t apply creams or lotions (such as human sunscreen) to cats. Always check the label.