Todayโs path rounds are on ๐๐ง๐ญ๐ข๐๐ซ๐๐๐ณ๐ ๐ญ๐จ๐ฑ๐ข๐๐ข๐ญ๐ฒ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ง๐ญ๐ข๐๐ซ๐๐๐ณ๐ is actually a pretty common toxicity, especially in the spring and fall. Animals will drink antifreeze because it tastes sweet!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
While any species can get this, typically it is seen in dogs and cats.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Antifreeze contains a compound called ๐๐ญ๐ก๐ฒ๐ฅ๐๐ง๐ ๐ ๐ฅ๐ฒ๐๐จ๐ฅ, because it absorbs water. Unfortunately for our pets, this compound is very toxic, and also tastes sweet, which entices them to drink it.
On its own, ethylene glycol is not very toxic, and is usually excreted through the kidneys without causing many issues. However, some of this compound is processed into ๐ ๐ฅ๐ฒ๐๐จ๐๐ฅ๐๐๐ก๐ฒ๐๐ and ๐ ๐ฅ๐ฒ๐จ๐ฑ๐ฒ๐ฅ๐๐ญ๐ in the liver, which are ๐ง๐๐ฉ๐ก๐ซ๐จ๐ญ๐จ๐ฑ๐ข๐ compounds. This means that they are directly toxic to the tubules in the kidney.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
When these compounds reach the kidney for excretion, they cause severe damage to the cells. This damage leads to ๐ซ๐๐ง๐๐ฅ ๐๐๐ข๐ฅ๐ฎ๐ซ๐. Additionally, these compounds are quite acidic, which can lead to ๐๐ญ๐๐ฑ๐ข๐ (difficulty walking) and depression.
If the animal survives the initial onset of disease, they arenโt quite out of the woods! These compounds can also form ๐จ๐ฑ๐๐ฅ๐๐ญ๐ ๐๐ซ๐ฒ๐ฌ๐ญ๐๐ฅ๐ฌ, which can embed themselves in the kidney tubules and cause further damage. Occasionally, these crystals can also be seen in the brain. Wild!
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Typically the veterinarian will start with bloodwork in these cases, which can help them detect the ๐๐๐ข๐๐จ๐ฌ๐ข๐ฌ in the bloodstream from these compounds. From there, they might think to do a ๐ฎ๐ซ๐ข๐ง๐๐ฅ๐ฒ๐ฌ๐ข๐ฌ, where the urine is examined for crystals. Large numbers of oxalate crystals are considered ๐ฉ๐๐ญ๐ก๐จ๐ ๐ง๐จ๐ฆ๐จ๐ง๐ข๐ (nothing else it could be) for ethylene glycol toxicity, so if these crystals are seen, the veterinarian can begin treatment.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Treatment depends on how long it has been since the animal ingested the antifreeze. If caught quickly, the veterinarian will administer medications that bind the toxin to prevent its absorption into the body. If the toxin has already been absorbed, ๐๐ญ๐ก๐๐ง๐จ๐ฅ or ๐-๐ฆ๐๐ญ๐ก๐ฒ๐ฅ๐ฉ๐ฒ๐ซ๐๐ณ๐จ๐ฅ๐ can be administered to block the liverโs processing of ethylene glycol. If the animal has already entered liver failure, then unfortunately supportive treatment is the only option left. The prognosis for these animals is very poor.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-3) Examples of kidneys following ethylene glycol toxicity. If you look carefully at the outer section of the kidney, you can see small granules. These are the oxalate crystals!
4) An example of one of these kidneys under the microscope. Doesnโt look too impressiveโฆ
5-6) Until you ๐ฉ๐จ๐ฅ๐๐ซ๐ข๐ณ๐ the sample! Polarization is when the light particles are aligned to a specific wave, and happens to highlight these crystals. Super cool!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Grauer GF. Overview of Ethylene Glycol Toxicity. Merck Veterinary Manual 2016.
Photos 1-6 ยฉ Noahโs Arkive contributors Crowell, Taylor, Jakowski, Peterson licensed under CC BY-SA 4.0.
