Todayโs path rounds are on ๐ซ๐ฎ๐๐๐๐ซ ๐ฃ๐๐ฐ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฎ๐๐๐๐ซ ๐ฃ๐๐ฐ is one of many possible consequences of ๐ซ๐๐ง๐๐ฅ ๐๐๐ข๐ฅ๐ฎ๐ซ๐, and results in jaw bones that are unusually soft and malleable, like rubber! This condition is more scientifically known as ๐ซ๐๐ง๐๐ฅ ๐๐ข๐๐ซ๐จ๐ฎ๐ฌ ๐จ๐ฌ๐ญ๐๐จ๐๐ฒ๐ฌ๐ญ๐ซ๐จ๐ฉ๐ก๐ฒ.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
We most commonly see this in dogs!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
When the kidneys fail, they do not excrete enough ๐ฉ๐ก๐จ๐ฌ๐ฉ๐ก๐๐ญ๐, leading to a ๐ก๐ฒ๐ฉ๐๐ซ๐ฉ๐ก๐จ๐ฌ๐ฉ๐ก๐๐ญ๐๐ฆ๐ข๐ (elevated phosphate in the blood). The increased phosphate in the blood combines with ๐๐๐ฅ๐๐ข๐ฎ๐ฆ dissolved in the blood, forming a solid. Because this calcium is now in a solid form, it can no longer be used by the cells, creating a ๐๐ฎ๐ง๐๐ญ๐ข๐จ๐ง๐๐ฅ ๐๐๐ฅ๐๐ข๐ฎ๐ฆ ๐๐๐๐ข๐๐ข๐๐ง๐๐ฒ. The body responds to this calcium deficiency by increasing calcium reabsorption from the bones, making them extremely weak and brittle. To try and counteract the weakened bone, the body lays down ๐๐ข๐๐ซ๐จ๐ฎ๐ฌ ๐ญ๐ข๐ฌ๐ฌ๐ฎ๐ (scar tissue) to try and maintain bone structure. However, this tissue is extremely malleable, producing a rubber-like substance! For unknown reasons, this process most commonly occurs in the jaw.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Unfortunately for these dogs, they are at an increased risk of losing teeth and bone fractures. Often, their jaws do not close properly as well, causing drooling and ๐๐ฒ๐ฌ๐ฉ๐ก๐๐ ๐ข๐ (difficulty eating).
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The veterinarian will often feel the jaw itself, which combined with findings of renal failure and elevated ๐ฉ๐๐ซ๐๐ญ๐ก๐ฒ๐ซ๐จ๐ข๐ ๐ก๐จ๐ซ๐ฆ๐จ๐ง๐ (the hormone that controls blood calcium levels), allows a diagnosis of โrubber jawโ to be made.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Usually treatment involves low phosphorous diets or ๐ฉ๐ก๐จ๐ฌ๐ฉ๐ก๐๐ญ๐ ๐๐ข๐ง๐๐๐ซ๐ฌ, to try to reduce the hyperphosphatemia. This is of course combined with managing the renal failure itself, as that is the primary cause!
๐๐ก๐จ๐ญ๐จ๐ฌ
1) A dog with โrubber jawโ showing a very flexible jaw structure! Weird.
2) An X-ray showing the bone loss in the jaw. Normally bone is quite white on X-rays!
3) A cross-section of a head. Normally you would expect to see bone here, but instead we see pale, grey-ish fibrous tissue.
4-5) The skull of a dog that had rubber jaw, showing the extensive loss of bone.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Grunberg W. Fibrous osteodystrophy in animals. Merck Veterinary Manual 2021.
Photos 1-5 ยฉ Noahโs Arkive contributors King, Dhein, Crowell, Jakowski licensed under CC BY-SA 4.0.
