Is metabolic bone disease permanent in lizards? Is there a way to treat it?
I found an iguana in what I believe were the intermediate stages of metabolic bone disease (MBD). All four of his hands and feet were swollen and his mobility was somewhat hindered by stiff joints in his legs. I've corrected his diet and environment, and he appears to be more active now than when I found him, but will he recover completely? With as much literature as I've read on the subject, I haven't found one piece that says the symptoms of MBD aren't permanent. Assuming that it was caused by the lack of a sufficient amount of calcium as well as the absence of proper lighting, will he recover now that he is under better care?
Good questions! Now, I have one for you: have you taken your rescue iguana in to see a herp veterinarian? While diet and lighting are vital for recovery, herp vets have an arsenal of medications to assist in the treatment of MBD. One hormone, called calcitonin salmon, can really speed up recovery by causing the bones to stabilize and heal more rapidly. If your vet feels that additional treatment with calcitonin is warranted, it can dramatically change the outcome of the disease in some cases.
I have discussed this condition in my column previously, so please check it out, as it is in the archives.
Sometimes, MBD can be confused with other diseases, so if you haven’t had your iguana to a herp vet to confirm the diagnosis, I would recommend that you do so, to make sure that it truly is suffering from MBD and to make sure that it doesn’t have any other problems. Nothing says your iguana can only have one problem at a time, and blood work, radiographs and other tests can help determine exactly what it does have. Other conditions that come to mind are renal (kidney) disease causing gout, bacterial infection and parasites, to name a few.
If your lizard is only suffering from MBD, and if there are any fractures present, there is always the chance that the fractures could heal improperly, resulting in abnormally-shaped limbs. Without surgery to break and correct the deformities, which is not normally recommended, these are likely to be permanent. However, there is often some bone remodeling that occurs as the lizard regains use of the limbs. This may take quite some time to occur.
Once an animal has recovered from MBD and its diet and husbandry have been appropriately corrected, it should be able to completely recover and live a long, healthy life. You must recognize, however, that an animal that has recovered from MBD is not immune to it, and could actually suffer from it again, should the conditions in which it is maintained not be permanently corrected. In some cases, the kidneys may be permanently affected by long-standing nutritional and environmental abnormalities, and this could result in a shortened lifespan for the iguana. Kidney disease may be controlled with various treatments, but often the damage is permanent.
So, the short answer to your question is that an iguana that has recovered from MBD may have bone deformities, but if the organ systems are fully functional, it should be able to live a relatively normal life. It was good of you to rescue your iguana, but to be safe, please have it evaluated by a herp vet to ensure that there aren’t any other problems requiring treatment.
Margaret A. Wissman, DVM, DABVP has been an avian/exotic/herp animal veterinarian since 1981. She is a regular contributor to REPTILES magazine.
Need a Herp Vet?
If you are looking for a herp-knowledgeable veterinarian in your area, a good place to start is by checking the list of members on the Association of Reptilian and Amphibian Veterinarian (ARAV) web site at www.arav.com. Look for DVMs who appear to maintain actual veterinary offices that you could contact.