Metabolic Bone Disease: What You Should Know
Advice from BeWild Exotic Animal Education and Rescue expert
Zen Habitats: What is MBD?
Nicole: MBD stands for metabolic bone disease. Another term for this is NSHP, or nutritional secondary hyperparathyroidism. Basically, MBD is a nutritional disease that happens when an animal does not receive enough calcium, vitamin D3, or UVB light. This can cause the animal to have trouble walking and become very weak, as the animal’s body will start to pull calcium from the bones to support vital organ functions. When the bones become weak, the animal is prone to fractures and can have permanent spinal deformities. In severe cases, the animal will die from organ failure.
Zen Habitats: Can MBD be prevented?
Nicole: Yes! MBD can absolutely be prevented with proper diet, supplementation, and lighting. Each species of reptile has different natural histories and needs, so be sure to research your species extensively before acquiring a new pet. Lizards and chelonians (turtles and tortoises) are more prone to MBD than snakes, as snakes have whole prey diets and do not need additional supplementation. In the wild, lizards and chelonians have incredibly varied diets, so captive diets are often insufficient in nutrients and must be supplemented. Most lizards and chelonians also require special UVB lighting, and these bulbs need to be replaced every 6-12 months. For high-UVB species like bearded dragons and chameleons, we recommend long, linear T5 or T8 UVB bulbs.
Zen Habitats: What symptoms may indicate MBD?
Nicole: Symptoms of MBD include curved bones in the legs and arms; weak and rubbery lower jaw; kinks in the spine and tail; general stuntedness and small size; shaking and trembling; lethargy and weakness; inability to walk or climb. In chelonians, they will often have soft and deformed shells.
Vern, a young panther chameleon with a weakened lower jaw and limb deformities due to severe MBD. Unfortunately, his condition was too severe, and he passed away despite vet care and treatment.
Zen Habitats: What Can Cause MBD?
Nicole: MBD is caused by not supplementing with calcium, vitamin D3, or providing UVB light. Not all species of reptiles need additional supplementation or lighting, but it is necessary for certain species such as bearded dragons, chameleons, and iguanas.
Zen Habitats: How is MBD diagnosed?
Nicole: While many experienced owners can recognize the symptoms such as curved bones or kinks in the spine, the owner should see an exotics specialist veterinarian for a diagnosis. Your veterinarian can run blood tests to determine the calcium levels and do X-rays to check for any fractures in their limbs.
Zen Habitats: How common is MBD?
Nicole: Despite the prevalence of information available online and from veterinarians, MBD remains very common in captive reptiles. We get in many surrendered leopard geckos, bearded dragons, and chameleons with metabolic bone disease every year.
Sybil, a female leopard gecko with leg deformities and kyphosis, or spinal kinks, from MBD. She is also stunted in size.
Zen Habitats: What are treatments?
Nicole:In a mild case, you can typically reverse the symptoms with proper diet, supplementation, and by adding a UVB light. However, severe cases need oral calcium supplementation with a prescription-strength liquid calcium and oftentimes syringe feeding if they are not eating by themselves.
Zen Habitats: What can be the long-term effects of MBD?
Nicole: MBD can cause permanent bone deformities, fractures, and stuntedness. If an animal recovers from a severe case of MBD, then its bones will strengthen but never fully straighten. This may make them less mobile or unable to climb and jump.
Zen Habitats: Is there special ongoing care for reptiles that have had MBD?
Nicole: With animals that are actively recovering from MBD, we make sure to keep them in short enclosures with no tall decor pieces while they undergo treatment. Animals with MBD have very fragile bones, so a fall can cause bone fractures. Animals that have recovered from MBD are on a spectrum as far as their abilities. Some can go back to a normal life and can climb and jump, especially if they were a mild case. However, other animals may be unable to climb and should be permanently kept in lower enclosures.
Orion, a veiled chameleon with weak, curved limbs from MBD. In this picture, he could not walk by himself due to weakness. With proper treatment, he made a full recovery!
Zen Habitats: Is MBD common for both lizards and chelonians?
Nicole: We see MBD most commonly in chameleons, bearded dragons, and leopard geckos. We have only seen MBD once in a chelonian, as many pet chelonians are kept outdoors with sunlight, which has very high levels of UVB light.
Zen Habitats: Are there differences between MBD in chelonians and lizards?
Nicole: Yes. While you would see general weakness and lethargy in both, a chelonian will have evidence of MBD mostly in its shell. Their shell may be soft due to low calcium stores, as it is made of bone underneath a layer of keratin. It also may be smaller than normal or malformed.
Cloud, an adult leopard gecko, with moderate metabolic bone disease. You can see the curved limbs, but luckily his spine is not affected.
Zen Habitats: What advice do you have for new and current owners regarding MBD?
Nicole: Make sure to do lots of research on your particular species! Each species of reptile has different needs as far as percentage and strength of UVB lighting, types of supplementations and calcium, and components of the natural diet with different levels of nutrients. Find a good exotics vet before getting your new pet. Try to network with other owners who have experience with that species. For current owners, always be willing to learn! Husbandry changes as we learn new things about nutrition and science, and it has changed significantly even in the last 10-20 years.