Water Toxicity and Pets

By Dr. Joe Musielak

Did you know that too much water can cause problems (other than drowning) for your pet?

This summer we are having MUCH warmer than usual temperatures in Western Washington. Dogs will often drink too much water in an effort to cool off.

As many dog owners know, some dogs do not have an “off” switch when it comes to eating -- many will eat until there is no more food. Some dogs that are overheated will do the same with water. This can cause a sudden drop in the sodium levels in the blood, resulting in water moving into brain cells and causing them to swell. Water toxicity, or hyponatremia, can lead to severe neurologic problems such as seizures and even death. 

Remember to be aware of this not just at the water bowl. This can occur in dogs swimming and playing in freshwater lakes or rivers, or when our furry friends drink from the never-ending fountain that is the toilet bowl. Keep a watch on how much water your dog is ingesting and give her rest breaks during playtime.

The early signs of water toxicity can literally be any sort of abnormal neurologic behavior starting with lethargy/vomiting to ataxia (wobblyness) progressing to seizures and death. 

For dogs that are spending the day at the beach, the opposite can happen. Dogs get thirsty playing, and salt water looks JUST like fresh water and -- you guessed it -- they drink too much of it and can get salt poisoning (hypernatremia). If they don’t vomit, they keep all that salt in their system, the sodium moves from the gut to the blood to the brain and, again, the brain swells. Always take fresh drinking water with you when you and your pup go to the beach, and offer it to him frequently.

We also see the second scenario with dogs and even cats that are deprived of normal amounts of water (e.g., a cat that gets locked in a hot garage for a day or more in warm weather). Sodium levels go up and the brain swells. 

Treatment IS possible with prompt, appropriate IV therapy by a veterinarian. This is not something that can be done at home. The sodium levels must be brought back to normal slowly, or the sudden changes can cause irreversible damage. 

If you suspect a problem, contact or go to your veterinarian as soon as possible, as water toxicity progresses quickly.

Article added 6.30.15