Water intoxication is a little known swimming hazard – I know it sounds a little “out there,” but it happens, and your vet might not know what to look for. It occurs when dogs drink too much water too quickly. This can happen in humans, too (most frequently athletes), but for the most part, we know when to stop drinking water. Dogs, on the other hand, are more likely to accidentally drink large quantities of water while swimming or playing a particularly long game of “bite the hose.”

What is water intoxication?

When a mammal ingests too much water, the electrolyte balance is disturbed. We need things like sodium and chloride to keep a good balance of water both inside and outside of our cells. When the body is inundated with water, cells can begin to swell, and when cells in the central nervous system (the brain) start to swell, the consequences are life-threatening.

Water intoxication is relatively rare, considering how popular swimming is among our canine friends. It can occur in any dog, but small dogs seem to be at higher risk. It may also be under-diagnosed – the symptoms come on so quickly and are so shocking that veterinarians may miss the obvious. This is a perfect case when giving your veterinarian a detailed history can help save your pet’s life.

What are the signs?

Clinical signs may start with vomiting – often these dogs will vomit up a large amount of water and drool excessively. Other clinical signs are neurologic in nature because of the swelling in the central nervous system. A glassy-eyed appearance, excess urination and stupor are common early signs of water intoxication, coupled with extreme lethargy. Seizures can occur and all signs can rapidly progress to coma and death.

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How is it diagnosed?

If you notice these signs, get to your veterinarian’s office as quickly as possible, and be sure to give him or her a detailed history, including that your dog has recently been swimming or possibly ingested a large amount of water. Bloodwork will likely reveal very low electrolyte levels, especially sodium, and your pet’s neurologic exam will be abnormal in many ways.

What’s the prognosis?

Some dogs recover quite nicely over time – excess urination rids the body of extra water and allows the electrolyte levels to normalize. But in some pets, water intoxication is so severe that even despite treatment, they will go into respiratory arrest and die. In many of these cases, it’s mere hours after being a perfectly healthy, perfectly happy, swimming, playing dog.

You’ll seldom see a happier pup than one who’s frolicking in the water or diving headlong off of a dock. I am not suggesting that you keep your dog from swimming – just help your dog be sensible about it. Take plenty of breaks and monitor your dog’s water intake if possible.

Jun 15, 2015
Pet Health

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