What is gout?
Gout is a disease in which the body does not metabolize uric acid properly. Uric acid is a breakdown product of nitrogen, formed when protein is metabolized in the body. In the bloodstream, uric acid forms microscopic crystals.
Mammals excrete urea as the primary breakdown product of protein metabolism. Reptiles excrete nitrogen waste as uric acid, which is removed from the circulating blood by the kidneys. When an animal has gout, it does not eliminate uric acid effectively and it builds up in the bloodstream. There are two forms of gout.
- Visceral gout forms when gout crystals are deposited on or in internal organs.
- Articular gout forms when uric acid crystals are deposited in joints, usually in elbows, wrists, ankles, and toes.
Gout is a common problem in many reptiles, including terrestrial turtles. Aquatic turtles are not usually affected by gout because they excrete the majority of their nitrogenous wastes as urea or ammonia and produce only a small amount of uric acid. Chameleons, bearded dragons, and water dragons are the reptiles most commonly affected by gout.
How does protein play a role in gout?
All reptiles require dietary protein. Carnivores (meat eaters) require animal-based proteins and herbivores (plant eaters) require plant-based proteins. Proteins are made up of amino acid building blocks, and amino acids are an essential nutritional component for many bodily functions. Each different source of protein contains different levels of various amino acids, and each species of reptile is physiologically adapted to use the proteins and amino acids found in its natural diet.
"When protein breaks down, it creates uric acid."
When protein breaks down, it creates uric acid. A reptile's ability to manage uric acid depends on the amount of protein fed, the type of protein fed, the frequency it is fed, and the hydration status of the body. If uric acid is not excreted, it may accumulate in the joints, in the kidneys, or around other organs such as the liver, spleen, heart, or lungs. Sometimes, uric acid may accumulate in mucous membranes, such as the mouth.
What causes gout in reptiles?
Why gout occurs in reptiles is not entirely clear, but diets too high in protein or containing inappropriate proteins are a predisposing factor. Dehydration and altered kidney function are also key factors. In the case of starvation, an animal will use its own bodily resources, including proteins, for energy, which can lead to gout.
What are the signs of gout and how is it diagnosed?
In cases of articular gout, raised, cream-colored swellings may be noted on the joints of toes, ankles, elbows, or wrists. Typically, patients have trouble moving around because of joint pain and swollen joints. The mucous membranes of the oral cavity may have raised, whitish, spherical swellings (gout tophi).
"Typically, patients have trouble moving around because of joint pain and swollen joints."
Your veterinarian will gather a thorough history, perform a physical examination, evaluate the diet and environment (including water availability, humidity, and temperature). To accurately diagnose gout, your veterinarian will need to perform a blood test to measure the uric acid level in the bloodstream. They may request X-rays to assess joint damage and see if there are notable abnormalities in the kidneys. On X-rays or physical palpation, the kidneys may be enlarged.
In some cases, the veterinarian may cut (lance) a swelling on one of the joints and have the material in the swelling analyzed under the microscope for evidence of uric acid crystals.
How is gout treated?
Dietary management or modification is the primary focus of treatment, along with correcting environmental deficiencies. The animal may be hospitalized for proper hydration (fluid therapy) and supportive care. Surgery is occasionally used to "clean out" the joints; in severe cases, the damage to the joints is enormous and irreversible.
As in human medicine, medications may be used to treat gout in reptiles with gout, such as allopurinol and omega fatty acids. However, success is variable and treatment may be lifelong. Routine blood tests are often recommended to see how your pet is progressing and to see if the uric acid levels in the blood return to normal or get worse.
What is the prognosis for a reptile with gout?
In many cases, treatment must be continued for the remainder of the patient’s life. In general, the prognosis for reptiles with a severe case of gout is poor. The goal is to try and achieve a good quality of life through use of pain medication, proper hydration, dietary changes, and environmental modifications. In severe cases, euthanasia may be considered.
