by Kenneth L.
I will try to give the Readers Digest version as this is a complex topic. Proteins (animal or vegetable) from the diet are degraded to amino acids. Purine and pyrimidine bases are synthesized from the amino acids, primarily by the liver. Let's forget about the pyrimidines and focus on the purines. Purines are degraded (in most reptiles) to the end product, uric acid, which is cleared from the blood by the kidneys.
Gout comes in a few different forms: articular (in the joints), peri-articular (around the joints), and visceral (in the gut). It can also be classified as primary and secondary. Primary gout, such as humans get, comes from hyperuricemia (i.e., excessive uric acid in the blood) due to dietary factors or to a defect in amino acid metabolism. Secondary gout comes from hyperuricemia due to a problem in the excretion of uric acid such as renal disease. When this happens, urate crystal deposits can form in many places, hence, articular, peri-articular, and visceral forms. The deposits are called tophi and the disease is considered tophaceous gout.
Some animals, such as Dalmations may have genetic reasons for the formation of uric acid uroliths ("stones") and must take Allopurinol to inhibit the enzyme, xanthine oxidase, which is responsible for converting oxypurines to uric acid. Iguanas, which should be vegetarians, get gout when fed animal protiens which are high in purines. Chameleons usually get hyperuricemia due to dehydration or renal disfunction, a secondary gout. I see a lot of articular gout in chameleons. On X-rays this may appear similar to a bad arthritis and visually as swollen joints, usually on the extremities. For the sake of brevity, this is a very simplified version of a complex process.
The information provided on this site is for your consideration only. You should contact your veterinarian for specific questions concerning your chameleons.