Vitamin D Poisoning in Dogs

Did you know that in addition to causing a deficiency of vitamin K in dogs, rat poison can cause a vitamin D overdose?  Vitamin D is essential to the body, regulating the calcium and phosphorus levels in the body.  It also regulates the retention of calcium, aiding in the building of bones and the functioning of nerves and muscles.  Too much of the vitamin, like too much of many good things, can kill.

Rodent poison is the most common cause of vitamin D poisoning, but excessive supplementation of vitamin D or some drugs can also cause vitamin D poisoning.  All ages of dogs are vulnerable, but puppies and young dogs are more vulnerable.

Symptoms usually appear within twelve to thirty-six hours of ingesting rat poison, but the time line varies with the source of the vitamin D overdose.  The following symptoms may occur:  vomiting, weakness, depression, loss of appetite, increased thirst, increased urination, dark tarry feces containing blood, blood in vomit, loss of weight, constipation, seizures, muscle tremors, abdominal pain, excessive drooling, and death.

When you take your dog to the veterinarian, he will take a detailed history of what your dog eats and any supplements he gets.  He will also ask if the dog might have gotten into rat poison.  A complete blood panel, biochemistry profile, electrolytes, and urinalysis will be done.

If your dog has vitamin D toxicity, there will be abnormally high levels of calcium and phosphorous in the blood.  There may also be abnormally low levels of potassium in the blood, and abnormally high levels of nitrogenous waste products.  In some dogs, high liver enzymes and low levels of protein are present in the blood.  The urinalysis will show abnormally high levels of proteins and glucose in the urine.  In addition, some dogs show various blood clotting problems, such as bleeding from various places due to an excessive loss of platelets.

After these results come back, the veterinarian may test the levels of vitamin D in the blood directly and do an ECG to check on the dog’s heart.  Dogs with vitamin D toxicity may show abnormally slow heartbeat.

Vitamin D toxicity is an emergency requiring your dog to go in the hospital.  The first 72 hours are critical to saving the life of your dog.  The veterinarian may induce vomiting in your dog if he just ingested the rat poison or other source of vitamin D.  Otherwise, there are various drugs with bind the toxic compounds and keep the dog from absorbing more vitamin D.

The dog will probably also be on an IV to make sure he stays hydrated and his electrolyes balanced.  Flushing the dog with fluid will help him excrete excessive calcium through his urine, as well.

In some cases, dogs develop severe anemia and need blood transfusions.  Dogs often also get secondary bacterial infections when they have vitamin D toxicity.  Antibiotics may be prescribed to manage these infections.  Seizures are treated with an anti-seizure medication.

Due to the prolonged hospitalization required, treating dogs with vitamin D toxicity is very expensive and laborious process. To monitor the progress of therapy, periodic laboratory testing is required, including determining the dog’s calcium and phosphorous levels.

The best way to prevent vitamin D toxicity is to keep rat poison away from your dog and to consult with your veterinarian before supplementing the dog’s diet with anything.