Kidney Failure in Chameleons

One of the things that can cause chameleons to stop eating and become weak is kidney failure.  This disorder should be suspected in any chameleon that has two or more of the following signs: a lump just in front of its pelvis, inability to defecate (or pass eggs), fluid beneath the skin under its jaw or neck, dehydration even with plenty of water offered, a foul odor to its breath, swollen joints, bloodshot eyes, or white shiny deposits in the lining of its mouth.

Constipation and dystocia are due to the malfunctioning kidneys becoming so large that they physically obstruct the pelvic canal and prevent anything passing from the intestine or oviduct to the cloaca.  All the other signs are due to the kidneys not filtering the blood as they should.  Swollen joints, bloodshot eyes, and white deposits in the lining of the mouth are the result of crystals forming in the tissues and are signs of a very ill chameleon.

So why do chameleons seem so prone to kidney failure?

It is associated with two common husbandry errors, insufficient intake water and a lack of vitamin A in the diet.
Most chameleons will only drinking moving water.  Captive specimens require water to be dripped or gently sprayed on them throughout the day to insure that they are drinking enough. Do not assume that a chameleon is drinking just because you have provided a drip system, make sure you observe your chameleon is actually drinking. In the wild, a chameleon’s water also comes in the form of moisture in the air. This can be either through high relative humidity or by weather related such as fog, rain, or dew.  In captivity, particularly in central Arizona, it is quite challenging to reach a sufficiently high relative humidity (85-95% RH) for any length of time without completely saturating a cage with water many times a day. An ultrasonic humidifier placed in the same room as a chameleon’s cage may only bring that room up to 45-50% RH, too low for a chameleon stay healthy if it endures that low humidity 24 hours a day. Unless a lot of effort goes into creating a humid environment that is well ventilated, the chameleon will live in a much drier realm than its wild habitat. Even the veiled chameleon, a more arid-adapted species than many others in the pet trade, requires a few hours of high humidity every 24 hrs to do well. Assess your chameleon’s water intake daily and adjust the cage environment as needed to keep the air moist but fresh.  A well-hydrated chameleon has bulging eyes and skin that doesn’t wrinkle.  It also sheds easily and doesn’t have old skin cling to its toes, tail tip, or around the eyes.  If your chameleon shows any of these signs, it is likely under-hydrated and under enough water stress to put it at risk of kidney failure.
Many of the reptile vitamins on the market lack vitamin A.  Their advertising and labeling suggest that the beta-carotene they provide is an adequate substitute for vitamin A with chameleons and other reptiles.  Unfortunately, there seems to be no rigorous scientific data to support this belief.  Many chameleons and other insectivorous and carnivorous reptiles with overt vitamin A deficiencies that were fed supplements containing beta-carotene.  A vitamin A deficiency changes the structure of certain cells within the kidney.  As these cells become affected, the kidney is less efficient at processing wastes and moving them out of the body.  Over time, the waste products, known as urates, build up in the kidneys and cause them to enlarge.  As the kidneys get bigger, they start to interfere with other body functions and can cause constipation and dystocia.  The kidney also serves a vital role in balancing calcium and phosphorus levels in the body so once it is damaged then other organs are affected.  

How is Kidney Failure diagnosed and treated?

Various tests may be performed to confirm kidney failure.  A blood sample will look at factors such as calcium, phosphorus, uric acid, albumin, and hematocrit (a measure of red blood cell numbers).  A radiograph or cloacoscopy (inserting a “telescope” into the chameleon’s cloaca) may help distinguish enlarged kidneys from other masses.  Once it is confirmed, the question becomes whether it is reversible or irreversible.  While it is sometimes obvious when a chameleon has irreversible kidney failure, it is not always so predictable.  Generally, a course of treatment may be tried and if the chameleon doesn’t improve within a few days, it is likely not reversible.  Whether to treat or not is an individual decision and may be based on the chameleon’s quality of life.  Sadly, most chameleons diagnosed with kidney failure are suffering and their suffering will not be relieved with treatment.  For those chameleons, euthanasia is the most humane option.