Kidney related diseases are a major cause of illness and death in captive lizards. Improper captive husbandry and diet are the most common predisposing causes of chronic renal failure — which is typically seen in adult lizards. Whereas acute onset of renal disease is often due to infectious or toxic causes (including medications) and appears to affect any age animal and is typically more sporadic in occurrence.

Anatomy and Physiology

To properly understand and appreciate the problems of renal disease in lizard species — a few basics must be understood. All lizards remove the by-products of protein metabolism through the excretion of uric acid (urates) through the kidneys. High levels of uric acid can cause gout in dehydrated animals.

In lizards, the urine produced by the kidneys flows down a duct to the cloaca, where it then passes into the bladder (if present) or cranially into the distal colon for storage prior to excretion.

History and Physical Examination

Acute renal disease in lizards is typically characterized by a relatively rapid onset of depression, lethargy, production of little or no urine, and weakness. The medical history may reveal the prior use of drugs that can be toxic to the kidneys (i.e., aminoglycosides) or exposure to toxins or poisons. Frequently these animals were well maintained with a good level of nutrition and a reasonable level of husbandry. Therefore, on physical examination, most lizards with acute renal disease will be of a good weight and reasonable body condition.

In chronic renal disease, there will often be husbandry (low humidity, mild long-term water deprivation/chronic low grade dehydration) or nutritional factors (high protein diets, excess vitamin D3 supplementation) that may indicate the potential for renal disease. These animals tend to have a history of reduced appetite, poor weight gain or weight loss, and occasionally increased drinking in the animal. On physical exam the animals are usually of poor body condition, dehydrated, and may have some abdominal pain.