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CHAPTER 33 III Lizards 391

C

Figure 33-21, cont’d • For legend see opposite page. Figure 33-22 • Chameleon (seen from above) with multiple
insufficiency fractures of its midtail and distal tail.

painful. This pain can lead to a reluctance to eat and a probably metabolic bone disease (Figures 33-22 and
commensurate weight loss. Since the teeth retain their 33-23). If not, fracture becomes the more likely
normal density, but the surrounding bone loses its possibility.
density, the teeth appear to have no visible connection
with the associated jaws when viewed radiographi- Intestinal Impaction and the Perils of
cally. This ghostly appearance is sometimes described Dietary Change
as “fl oating.”
A reduced calcium content also causes bones to Healthy diets are also capable of causing problems, for
soften, particularly the mandible, spine, and pelvis, example, increasing the amount of food or changing

which can lead to insufficiency fracture and deformity. its composition can lead to intestinal impaction. Even
I have seen some iguanas whose pelvic canal was altering the frequency of feeding can lead to constipa-
nearly obliterated to the extent that their hips were tion in lizards and other reptiles.
situated side-by-side, as seen in a dorsoventral Some diets cause localized mineral build-ups,
radiograph. known as enteroliths, to form in the intestine and even-
tually block it. These stone-like objects (Figure 33-24)
can also lead to intestinal twisting (volvulus) or entrap-
ment (incarceration).
Differentiating Traumatic Fracture
from Insuffi ciency Fracture
Blockage Secondary to Intestinal
The cause of some of these deformities, especially Foreign Body or Material
those affecting the spine, is not always clear, but in
general, trauma and hyperparathyroidism are the top Intestinal impaction can also be caused by sand or
contenders. These possible causes are based on bone gravel that the lizard picked up in its enclosure (Figure
density and the presence of any accompanying skeletal 33-25). Foreign bodies are also capable of causing

lesions such as long bone fractures or spinal lesions blockage of the bowel, as exemplified by an iguana
(new or old). If the bone appears osteopenic and there that ate a metal screw accidentally left on the fl oor near
are other spinal deformities or fractures, then it is its enclosure (Figure 33-26).

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