Antifreeze Poisoning in Dogs

Antifreeze Poisoning in Dogs

There are several household items that are toxic to our dogs, one of the most problematic being antifreeze. Some of the reasons this holds true are:

  • Antifreeze has a smell and taste that our dogs are attracted to.
  • The availability of antifreeze is quite high - It is commonly spilled on the garage floor or dumped into the street when changed.
  • The lethal dose of antifreeze when consumed by dogs is very small. It only takes about two tablespoons to be lethal in a dog.
  • Generally speaking there is a lack of public awareness on how toxic antifreeze is to dogs.

Signs & Symptoms of Antifreeze Poisoning in Dogs

The signs and symptoms of antifreeze poisoning are time dependent, meaning that certain symptoms will be noticeable based on how much time has passed since consumption. The following are organized by the time frame of thought consumption of EG.

Within the first 12 hours:

  • Depression
  • Vomiting
  • Increased water consumption
  • Stumbling or wobbling
  • Hyper-excitability
  • Not eating
  • Seizure activity may be observed

During this phase of poisoning, your dog may exhibit characteristics similar to someone who is drunk.

Within 24 hours:

All of the above symptoms can be exaggerated by this point. During this time the cardiovascular system is affected, causing in addition to the above list:

  • Rapid breathing
  • Panting

Within 72 hours:

At this point the kidneys have suffered a great deal of damage and the likelihood that kidney failure will occur is almost definite.

  • Marked Depression
  • Stumbling or generally uncoordinated walking
  • Severe vomiting and diarrhea
  • Dehydration
  • Various forms of paralysis
  • Decreased motor function

Causes of Antifreeze Poisoning in Dogs

The chemical in antifreeze is called Ethylene Glycol (EG); this is highly toxic to our dogs and causes extensive kidney damage almost immediately after consumption. When antifreeze is consumed the body starts absorbing the toxin from the GI tract, and there is a peak concentration in the bloodstream at about three hours post consumption. Once the EG is metabolized through the liver and kidneys, an oxidation type of reaction begins to occur. It is during this phase that liver and kidney damage begins. The oxidation process causes Calcium Oxalate crystals to form, and an increase in the urine pH; these can be identified on a urinalysis test performed on an affected dog.

Diagnosis of Antifreeze Poisoning in Dogs

Diagnosis begins with a complete history and a physical exam of the dog. Your veterinarian will most likely do the following: 

  • EG Test Kit - There is a special test available that will show positive or negative for antifreeze consumption; however this test is usually ONLY accurate if it is run within the first 12 hours of consumption.
  • Urinalysis w/cytology - A urine sample will be collected and tested for pH level, and most importantly the sample will be examined under a microscope looking for a high number of oxalate crystals, as these are the byproducts of the EG once the kidneys have metabolized the toxin.
  • BUN and Creatinine - These are blood tests that are performed to evaluate the function of the kidneys.
  • Blood Gas - This test will give a pH of the blood.

Treatment for Antifreeze Poisoning in Dogs

Your veterinarian will most likely admit your dog to the hospital and provide the following:

  • Administer emetic drugs to induce vomiting.
  • Administer activated charcoal - This gives the toxin something to bind to, so as to slow down the absorption process for the body.
  • Administer intravenous fluids to include sodium bicarbonates, not only to control dehydration but also to balance hydration.
  • Administer Fomepizole - This is the drug of choice when treating EG poisoning. This product is given intravenously and it stops any further metabolizing of the EG.
  • Provide an extensive amount of nursing care to keep your dog comfortable through the treatment process.

The prognosis will depend on how much time passed before treatment began, and of course how much antifreeze was consumed.  You can expect your dog to stay in the hospital for several days to several weeks, and it is not uncommon for a veterinarian to transfer an antifreeze case to a specialty hospital to complete treatment.

Prevention of Antifreeze in Dogs

Preventing your dog from consuming antifreeze is easy:

  • Keep any antifreeze in your home sealed and in a cabinet away from dogs.
  • Make sure your vehicles do not leak antifreeze and that all spills are cleaned thoroughly.
  • Do not allow your dog to drink out of puddles.
  • Do not let your animal roam, as they could be exposed to antifreeze at another home.

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