Metabolic Bone Disease
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NUTRITIONAL SECONDARY HYPERPARATHYROIDISM
(Better Known As “Metabolic Bone Disease”)
By Eric Klaphake, DVM and Martin Orr, DVM
Nutritional secondary hyperparathyroidism (NSHP) is the most common presentation of metabolic
bone disease (MBD) in reptiles and amphibians, especially iguanas. MBD encompasses a number of
syndromes including NSHP, osteoporosis (bone mass loss), osteomalacia (failure of adult bone to calcify),
rickets (juvenile form of osteomalacia), fibrous osteodystrophy (excessive bone resorption and
replacement with fibrous tissue), or hypocalcemia (low blood calcium levels).
This can all get rather complex, but this attempts to simplify it without being condescending.
1. Assume all reptiles and amphibians are either clinical for MBD (showing outward signs) or sub-
clinical (it’s waiting to happen).
2. The second concept to understand is how calcium works. We all know that calcium is extremely
important to strong bones. But it is probably more important at the cellular level for muscle contractions
(especially the heart). It even plays a role in allowing blood to clot. So calcium is very important. Too
much can cause heart attacks and seizures, so there can be too much of a good thing.
3. The third concept is how calcium is taken in, monitored and maintained.
Natural sunlight or an indoor bulb with 5-12% UVB hits the skin, converting the inactive form of vitamin D3
into the active form. This is what determines how much calcium is absorbed from the intestine. Oral forms
of vitamin D3 (cholecalciferol) can cause excessive uptake of calcium and cause blood vessels and internal
organs to be calcified. This is how many rat poisons work. The sunlight or UVB will not work through
glass, plastic, fine screening, or if the UVB is more than 2 feet from the reptile and amphibians.
Calcium is ingested in the diet. It must be in an absorbable form and its ratio with phosphorus in the
diet should be 2:1 or more.
The kidneys ideally reabsorb calcium as urine is filtered, and selectively excrete phosphorus.
However, when the kidneys are dehydrated or damaged, needed calcium is lost and undesired
phosphorus is retained, skewing the ratio.
Blood carries the calcium to the muscles, along with all the hormones that regulate the calcium.
When blood calcium is low, things are bad.
Bone is the warehouse of calcium, and while some can be removed to meet muscle and clotting
needs, too much loss leads to rubbery bones that easily break.
So you can see, anything affecting a part of this process can mess everything up. In some cases, this
is easy to fix, but in most, recovery is long and drawn out at best. As the old saying goes, “prevention is
the best cure.” It is important to realize that we do not know the perfect set-up for any species or
individuals. Reptile/amphibian medicine is changing rapidly, thus it is important to keep in touch with your
reptile/amphibian veterinarians for the latest information.
How can you prevent this or help correct already existing problems?
By doing the following:
1. Feeding the recommended diet, in the correct proportions, at the correct temperature. See
species specific handouts or get the diet instructions directly from your veterinarian.
2. Use the correct bulbs, with correct levels of UVB, set up in the recommended manner, when a
natural sunlight can not be used. The UVB levels should be 5-12%, within 2 feet of the animal, with no
barriers between, and should be changed every 6 months.
3. Soak your reptile once daily for 30 minutes in a warm water bath. Certain species may not
have this recommended for them. Keep the temperature at what a small child should be bathed at, and
the water should only be one half the height of the reptile, less if they are sick or weak. This helps keep
them hydrated, and their kidneys at their peak level of function.
4. Do not use oral vitamins containing vitamin D3 or phosphorus. Do not use the sun sprays or
moon sprays. Pet stores often sell products in ignorance. If there is a new product you are interested in,
ask your veterinarian.
5. Do not feed any animal-based proteins such as monkey chow/biscuits, dog food, cat food, or
other meats to vegetarian reptiles, and only sparingly to the carnivores. These make our
reptiles/amphibians real big, real fast, but damages their kidneys, and severely shortens their lifespans.
Remember this when purchasing an older animal. It might have occurred in the past. They like the tastes
of these products, “but just cuz it tastes good don’t mean nit’s good for ‘em!”
What are the signs to look for in your reptile or amphibian?
1. Fractured legs
2. Inability to stand upright
3. Paralysis
4. Swollen “Popeye” arms and legs
5. Rubber jaw, upper jaw longer than swollen lower jaw
6. Finger, toe, tongue and pupil tremors
7. Stunted growth
8. Unable to eat, though hungry
9. Abnormal shell growth in turtles and tortoises
10. Scoliosis of the back (S-curved)
11. Inability to urinate and defecate
12. Weakness and collapse
13. Death
All of these are signs which indicate your reptile/amphibian needs to be seen by your veterinarian. There
are some diagnostic tests that can determine severity of the MBD, secondary complications (dehydration,
infection, liver disease), and the best course of action. Likewise, there are treatment regimes that can
buy more time or even correct the situation. It is important to realize, though, that MBD TAKES A LONG
TIME TO DEVELOP AND A LONG TIME TO CORRECT IN THOSE SITUATIONS WHERE CORRECTION IS
POSSIBLE!
(Better Known As “Metabolic Bone Disease”)
By Eric Klaphake, DVM and Martin Orr, DVM
Nutritional secondary hyperparathyroidism (NSHP) is the most common presentation of metabolic
bone disease (MBD) in reptiles and amphibians, especially iguanas. MBD encompasses a number of
syndromes including NSHP, osteoporosis (bone mass loss), osteomalacia (failure of adult bone to calcify),
rickets (juvenile form of osteomalacia), fibrous osteodystrophy (excessive bone resorption and
replacement with fibrous tissue), or hypocalcemia (low blood calcium levels).
This can all get rather complex, but this attempts to simplify it without being condescending.
1. Assume all reptiles and amphibians are either clinical for MBD (showing outward signs) or sub-
clinical (it’s waiting to happen).
2. The second concept to understand is how calcium works. We all know that calcium is extremely
important to strong bones. But it is probably more important at the cellular level for muscle contractions
(especially the heart). It even plays a role in allowing blood to clot. So calcium is very important. Too
much can cause heart attacks and seizures, so there can be too much of a good thing.
3. The third concept is how calcium is taken in, monitored and maintained.
Natural sunlight or an indoor bulb with 5-12% UVB hits the skin, converting the inactive form of vitamin D3
into the active form. This is what determines how much calcium is absorbed from the intestine. Oral forms
of vitamin D3 (cholecalciferol) can cause excessive uptake of calcium and cause blood vessels and internal
organs to be calcified. This is how many rat poisons work. The sunlight or UVB will not work through
glass, plastic, fine screening, or if the UVB is more than 2 feet from the reptile and amphibians.
Calcium is ingested in the diet. It must be in an absorbable form and its ratio with phosphorus in the
diet should be 2:1 or more.
The kidneys ideally reabsorb calcium as urine is filtered, and selectively excrete phosphorus.
However, when the kidneys are dehydrated or damaged, needed calcium is lost and undesired
phosphorus is retained, skewing the ratio.
Blood carries the calcium to the muscles, along with all the hormones that regulate the calcium.
When blood calcium is low, things are bad.
Bone is the warehouse of calcium, and while some can be removed to meet muscle and clotting
needs, too much loss leads to rubbery bones that easily break.
So you can see, anything affecting a part of this process can mess everything up. In some cases, this
is easy to fix, but in most, recovery is long and drawn out at best. As the old saying goes, “prevention is
the best cure.” It is important to realize that we do not know the perfect set-up for any species or
individuals. Reptile/amphibian medicine is changing rapidly, thus it is important to keep in touch with your
reptile/amphibian veterinarians for the latest information.
How can you prevent this or help correct already existing problems?
By doing the following:
1. Feeding the recommended diet, in the correct proportions, at the correct temperature. See
species specific handouts or get the diet instructions directly from your veterinarian.
2. Use the correct bulbs, with correct levels of UVB, set up in the recommended manner, when a
natural sunlight can not be used. The UVB levels should be 5-12%, within 2 feet of the animal, with no
barriers between, and should be changed every 6 months.
3. Soak your reptile once daily for 30 minutes in a warm water bath. Certain species may not
have this recommended for them. Keep the temperature at what a small child should be bathed at, and
the water should only be one half the height of the reptile, less if they are sick or weak. This helps keep
them hydrated, and their kidneys at their peak level of function.
4. Do not use oral vitamins containing vitamin D3 or phosphorus. Do not use the sun sprays or
moon sprays. Pet stores often sell products in ignorance. If there is a new product you are interested in,
ask your veterinarian.
5. Do not feed any animal-based proteins such as monkey chow/biscuits, dog food, cat food, or
other meats to vegetarian reptiles, and only sparingly to the carnivores. These make our
reptiles/amphibians real big, real fast, but damages their kidneys, and severely shortens their lifespans.
Remember this when purchasing an older animal. It might have occurred in the past. They like the tastes
of these products, “but just cuz it tastes good don’t mean nit’s good for ‘em!”
What are the signs to look for in your reptile or amphibian?
1. Fractured legs
2. Inability to stand upright
3. Paralysis
4. Swollen “Popeye” arms and legs
5. Rubber jaw, upper jaw longer than swollen lower jaw
6. Finger, toe, tongue and pupil tremors
7. Stunted growth
8. Unable to eat, though hungry
9. Abnormal shell growth in turtles and tortoises
10. Scoliosis of the back (S-curved)
11. Inability to urinate and defecate
12. Weakness and collapse
13. Death
All of these are signs which indicate your reptile/amphibian needs to be seen by your veterinarian. There
are some diagnostic tests that can determine severity of the MBD, secondary complications (dehydration,
infection, liver disease), and the best course of action. Likewise, there are treatment regimes that can
buy more time or even correct the situation. It is important to realize, though, that MBD TAKES A LONG
TIME TO DEVELOP AND A LONG TIME TO CORRECT IN THOSE SITUATIONS WHERE CORRECTION IS
POSSIBLE!