An Unlikely but Deadly Hazard-Vitamin D

By Beth Davidow, DVM DACVECC

The benefits of Vitamin D have been much in the news. Vitamin D is that funny vitamin that is produced in your skin after exposure to the sun, specifically ultraviolet B light.  Vitamin D from your skin is converted to the hormone calcitriol which regulates the calcium and phosphorus balance in your body.  Lack of Vitamin D can lead to rickets in children, a problem where the bones become overly brittle, don’t grow normally or deform. Lack of vitamin D is also a risk factor for osteoporosis in adults.  These diseases are why milk is supplemented with Vitamin D. 

Vitamin D’s recent newsworthiness has come from observational studies that have suggested that low Vitamin D may increase the risk of certain neurologic diseases such as multiple sclerosis, Alzheimer’s, and Parkinson’s.  In addition, low vitamin D levels may be a risk factor for some cancers and peripheral artery disease. Increased daily intake levels were recently recommended by the Institutes of Health leading many people, especially in locales with low sunlight, to start taking Vitamin D supplements

            Although a certain amount of a vitamin will improve your health, too much can lead to toxicity.  Daisy Mae, a 5yr female Basset hound cross, found her owner’s very concentrated liquid vitamin D supplement and drank the content of the bottle.  Daily recommended Vitamin D is about 600 IU for a child.  Daisy Mae drank about 1.2 million IU!  While normal Vitamin D will maintain the right amount of calcium and phosphorus for normal bone growth and strength, toxic levels of Vitamin D can lead to calcification of tissues other than bone.  In addition, the increased calcium and phosphorus in the blood can lead to acute insults to the kidney and possibly renal failure.

            The ASPCA National Animal Poison Center was consulted as soon as Daisy Mae presented to ACCES and they recommended aggressive treatment to try to prevent calcification of her tissues.  Daisy Mae was made to vomit and then given activated charcoal to try to bind up any of the vitamin D still left in her intestinal tract.  She was also given an intravenous lipid infusion.  This is a newer treatment for toxins that are fat soluble to try to pull the toxin out of the tissues.  She was also placed on IV fluids to try to flush any accumulating calcium out of her kidneys.

            However, after 24 hours, Daisy Mae’s calcium and phosphorus had both risen to higher than normal levels.  We then started furosemide, a medication to make her urinate more and to increase the calcium being excreted and a steroid.  The calcium and phosphorus stayed high so we then gave a medication called pamidronate.

            Despite all these treatments, Daisy Mae’s calcium and phosphorus remained stubbornly high for 10 days in ICU!  Finally, levels fell back to normal. Luckily, Daisy Mae never felt sick and the treatments were able to protect her from any adverse effects on her kidneys.

            Animals can get a similar toxicity from a Vitamin D type ointment called Calcipotriene, marked as Dovonex®, which is used to treat psoriasis.  Even as little as 1.25 teaspoons can cause problems in a dog.           

The lesson from Daisy Mae is to remember that even supplements and vitamins can be dangerous.  If your pet gets into a medication or supplement, contact your veterinarian, your local emergency veterinarian, or the ASPCA National Animal Poison Center as soon as possible.  Without treatment in this case, permanent renal damage could have occurred. Luckily, Daisy Mae is now home and doing great.