Metabolic bone disease – bone malformations

Veiled chameleon with Metabolic Bone Disease (MBD)
This veiled chameleon is severly misshapen. Who knows what problems it has next to rickets and MBD.
This veiled chameleon is severly misshapen. Who knows what problems it has next to rickets and MBD.

Metabolic bone disease is a common problem in pet reptiles. Unfortunately it is also a big problem in pet chameleons. Metabolic Bone Disease is caused by too little calcium in the chameleons body. It can be caused by too few calcium in the chameleons food, or by too few vitamin D. Vitamin D is necessary to obtain calcium from food into the body. Vitamin D can be produced by the chameleons own body through exposure to UV-B light.

Metabolic Bone Disease (MBD) means that the chameleons body will start to extract calcium from its own bones to use it for important bodily functions like muscle contractions, metabolism and nerve function. Extraction of calcium from the bones will make the bones very weak. They will break easily and will become too flexible to function normally.

MBD is more common in young chameleons than in old ones, as young chameleons need much more calcium to grow. But even an adult chameleon that had no problems all its life and had very strong bones can develop weak bones because of MBD as it extracts calcium from them.

It will take weeks to months for metabolic bone disease to develop. Consistently not supplying enough calcium and/or vitamin D will slowly develop the disease and make the symptoms progressively worse. The disease develops slowly, and will also resolve slowly when the chameleon gets proper care. Damage to the body because of MBD can be reversed in a large part, but not completely.

Veiled chameleon with Metabolic Bone Disease (MBD)
Veiled chameleon with Metabolic Bone Disease (MBD). Notice the “double joints” at the elbow, these are actually broken and bend bones. It cannot stand up properly.

Symptoms of metabolic bone disease in chameleons

An unhealthy veiled chameleon
Veiled chameleon with misshapen skull.

The symptoms of MBD in chameleons are:

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  • Broken bones
  • Very flexible bones
  • Curved legs
  • Unable to stand up on legs
  • Falling off branches easil
  • Constipation or egg-binding
  • General weakness
  • Organ damage, especially kidneysy
  • A “rubber” jaw
  • Mouth not closing properly
  • Not being able to shoot with its tongue
  • Easily getting infections in eyes and respiratory system
  • Low bone density on x-rays

The most noticeable symptoms are the broken and flexible bones. Broken bones can be seen as “double elbows” on the legs of the chameleon. The flexible bones can be seen as curved legs or the chameleon laying down on its legs in a weird curve.

How to prevent or cure metabolic bone disease

The method to prevent and to cure metabolic bone disease is the same: supply enough calcium and vitamin D to your chameleon. The best way to supply vitamin D3 is through UV-B light. Click on the links to read more about these subjects. Cool temperatures in the environment of your chameleon will also impede calcium absorption from food.

If you have a chameleon with a severe case of MBD you need to take extra care of it than just adding calcium and vitamin D. When it is unable to walk, you should get it a low terrarium with few branches and cover the floor with something soft like a towel. As these severe cases are prone to falling and to break bones, you have to make sure they fall softly and cannot climb high. If it refuses to eat  you might have to force feed it.

Always go to a vet that is specialized in reptiles when your chameleon has MBD or has symptoms of it. The vet can do x-rays to check for broken bones and could inject calcium and vitamins to give your chameleon an extra boost. The broken bones cannot be set in a cast as this could cause more breaks to occur at other places. The broken bones should heal by itself and will often stay in their broken position forever. Vets could also check the calcium and phosphorous levels in the blood of your chameleon to make a clear diagnosis on the cause of MBD.

If MBD is not treated, it is fatal for your chameleon.