By Margaret A. Wissman, DVM, DABVP
My juvenile iguana has a swollen left front forearm. He is in good health, eats well and is defecating normally. The lump or swollen arm feels hard and does not seem painful to him. Any information you can give me would be very helpful. Thank you.
You need to find a herp vet who can help you with your green iguana. A swollen limb often is a sign of metabolic bone disease, also called fibrous osteodystrophy. This occurs as a result of not enough dietary calcium, excessive dietary phosphorus, lack of vitamin D or rarely from a disease involving the parathyroid glands, liver or kidneys.
Often this condition starts with one swollen limb. Because the skeleton does not have enough calcium to keep the bones strong, the body puts fibrous connective tissue along the bones to provide additional support, making the limbs look bulky. Also, if a bone spontaneously breaks, it will also develop a swelling in that area.
One clear sign of early disease is if your iguana can only lift up the front half of the body, and drags the back half along the ground. Normal, healthy iguanas will lift the entire trunk and base of the tail up off the ground when walking.
Iguanas require full-spectrum lighting (with UVA and UVB provided by a light made for this purpose) or sunshine, unfiltered through glass or plastic) in order to utilize dietary calcium. Diets fed to green iguanas should be primarily vegetables, as fruits are too high in phosphorus.
There are other things that can cause a swollen limb. You didn’t say if your iguana was housed alone or not. Iguanas are, by nature, solitary creatures, and if several are housed together, toenails can cause puncture wounds, resulting in infections or abscesses.
So, there are several medical conditions that can cause a swelling of the leg, and they all require the expertise of a reptile veterinarian. Without treatment, metabolic bone disease will progress and cause, perhaps, permanent damage to your pet. Please don’t hesitate to find a veterinarian who is willing to help you with your pet.