Antifreeze Poisoning

GENERAL DESCRIPTION

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

• Antifreeze has a smell and taste that our pets 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 is very small.  It only takes about 2 Tablespoons to be lethal in a dog, and only 1/2 a Tablespoon to be lethal in a cat.
• Generally speaking their is a lack of public awareness of how toxic antifreeze is to pets.

SOURCE & CAUSE(S)

The chemical in antifreeze is called Ethylene Glycol (EG); this is highly toxic to our pets and causes extensive kidney damage almost immediately after consumption.  When antifreeze is consumed the body starts absorbing the toxin from the GI tract, and their 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 animal. 

SIGNS & SYMPTOMS

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 pet 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 when walking
• Severe vomiting and diarrhea
• Dehydration
• Various forms of paralysis
• Decreased motor function

DIAGNOSIS & TESTS

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

• EG Test Kit - Their is a special test available that will show positive for antifreeze consumption, however this test is usually ONLY accurate if it is ran 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 & MANAGEMENT

Your veterinarian will most likely admit your pet 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 i.v. fluids to include sodium bicarbonates to not only 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 Ethylene Glycol.
• Provide an extensive amount of nursing care to keep your pet comfortable through the treatment process.

The prognosis will depend on how much time has lapsed before treatment began and of course how much antifreeze was consumed.  You can expect your pet 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 & HELPFUL TIPS

Preventing your pet from drinking antifreeze is easy:

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