Calcium Deficiency

If you think your lizard has calcium deficiency (Metabolic Bone Disease- MBD) :

Signs and Symptoms of MBD

     Signs of metabolic bone disease include hard knobs in the long bones of the legs, bumps along the vertebral column of the back and tail, softening or hard swelling of the jaw, and softening of the plastron or carapace in turtles and tortoises. All of these signs may be felt before they can be seen, making a careful physical exam important. Visible signs of moderate to severe MBD include jerky gait when walking, tremors and twitches in the limbs and muscles of the legs and toes when at rest, and shakiness when being held.

     A common finding is a pliable mandible or maxillae - the jaw bones. This is the best evaluated with the mouth held open. To do this gently restrain the upper jaw and pull down on the dewlap with the other hand. Once the mouth is open, apply gentle posterior (behind) pressure (not lateral (side)) to the mandible, then the maxillae, with the index finger. Normally these bones should feel like solid bone; in small lizards the mandible may give a little laterally but should still feel solid. With MBD either jaw may feel pliable. As MBD worsens, posterior traction from the lower jaw musculature may foreshorten the mandible and an under bite develops. This is often aggravated by fibrous osteodystrophy that bows the mandible laterally.

     Juvenile lizards often retain the rounded infantile skull shape of hatchlings because the skull fails to grow and lengthen.

     Advanced cases of MBD include all the above signs plus anorexia and fractured bones. Severely deficient reptiles tend to be lethargic and may only be able to drag themselves along the ground. A reptile lacking the ability to lift it's body from the ground when sitting or walking often suffers from a moderate to severe case of MBD. Arboreal lizards spend all of their time on the ground as they lack the strength to grip and climb.

     The earliest and most consistent sign of MBD is partial to complete lack of truncal lifting. A normal iguana lifts its body or trunk, and proximal tail, off the ground while walking or if disturbed. Early in the course of MBD, an iguana drags its pelvis and tail along the ground while walking, yet is still able to lift the front half of it's body. As MBD progresses, the lizard drags the entire trunk while walking. In advanced MBD, the lizard can no longer lift the trunk, the legs move vigorously, yet the lizard is incapable of ambulation.

     Often, reptile keepers will miss some of the first signs of MBD and only realize there is a problem when the animal suddenly seems to have a lame leg or broken toes. Metabolic bone disease often makes the bones weak, brittle and spongy. Normal activities like climbing or jumping and landing hard on an object could cause a broken bone very easily in an animal with MBD.

     Lameness, or reluctance to move, can result from single or multiple fractures. In iguanas, fractures are seen frequently in the proximal to midshaft femur (thigh), midshaft humerus (upper arm), distal radius (lower inside arm), and ulna (outer lower arm), and less commonly on the tibiotarsus. Distal radial and ulnar fractures can form a false joint and shift weight-bearing well proximal from the front foot. A single fracture, with or without a history of trauma, should always arouse suspicion of MBD.

     Fibrous osteodystrophy generally affects the long bones or the jawbones. Often the underlying bone is fractured but stable. Superficially, the long bones look well-fleshed, even robust. However, with palpitation, the legs have a firm feel more reminiscent of bone than flesh. Fibrous osteodystrophy does not affect all bones equally or symmetrically.

     Kyphosis (hump in spine), lordosis (forward curvature of the lower spine), and scoliosis (curvature or rotation of the spine- laterally) are less common and occasionally cause rear limb paresis (slight paralysis). Paresis generally improves with treatment, paralysis is a less common sequela.

     Generally, there is a gradual decline in appetite and weight loss. If the jawbones are affected, the patient may want to eat but has difficulty doing so. Lack of growth or weight gain in growing lizards is another indication of MBD.

     Radiographs are not essential for diagnosis but are useful to assess fractures, confirm suspicion of MBD, and serve as a basis for subsequent evaluation of the progress of therapy. Radiographically, there is an overall decrease in bone density. Poor bone contrast from soft tissue is especially notable in the pelvis and transverse processes of the caudal vertebrae. In truly severe cases, there may be little definition between bone and soft tissue. ..."

What is Metabolic Bone Disease?

      Metabolic bone disease is one of the most common nutritional deficiencies affecting captive reptiles. It is often the direct result of:

1. diets that are very low in calcium, and too high in phosphorus
   
   
   • Diets lacking bone are a common cause of MBD for carnivorous reptiles. Lizards or Crocodilians fed organ meat (liver, heart, or gizzards) or meat without bone (chicken, beef or hamburger) develop MBD. This is because lean beef and hamburger have a Ca:P (calcium to phosphorus) ratio of 1:16, beef heart, 1:38. Therefore, even with CA supplementation, these products have a severely negative Ca:P ratio. Whole rodents, birds or fish have a positive Ca:P ratio because of their skeletal bones. Perhaps this is one reason MBD is extremely rare in mice eating snakes.
     
     
   • Insects also have a negative Ca:P ratio; therefore, insectivorous reptiles and amphibians are also prone to MBD. All insects should be fed a Ca-rich diet for 2 to 3 days prior to being used as food or should be dusted with Ca carbonate (CO3) just prior to being used as food. A more balanced diet for insectivores should include baby mice or whole fish.
     
     
   • Multivitamins often contain Ca but not enough to prevent MBD. Many commercial reptile diets are Ca deficient.
     
     
2. Often combined with improper husbandry practices such as:
   
   
   • keeping the animal at too low temperature ranges causing improper digestion of nutrients;
     
     
   • Improper lighting such as not using UVB florescent lights, or having the UVB florescent set up improperly, or using too old a UVB florescent;
     
     
   • And or not exposing the reptile to unfiltered sunlight on occasion.
     
     
     • -In addition, lack of exposure to UV light or insufficient vitamin D3 supplementation can induce MBD. UV lights are thought to be essential in basking species for photochemical production of the active form of vitamin D, which in reptiles, is believed to be cholecalciferol or vitamin D3. UV irradiation in the 290 to 320 nm wavelengths catalyzes production of cholecalciferol in mammals, and it is assumed this is also true for reptiles.
       
       

Fibrous Osteodystrophy

     Variously called secondary nutritional hyperparathyroidism, osteomalacia, renal rickets, osteogenesis imperfecta, cage paralysis, osteodystrophia fibrosa cystica, etc., this author prefers the specific term fibrous osteodystrophy for it most properly denotes the pathological lesions exhibited in affected individuals.

     The etiology may involve disorders originating in the parathyroid glands, intestine, kidneys, liver, thyroid, and bone. Realizing fully that many more factors may enter the equation yielding the final answer. For the purpose of exposition, comments will be confined to that form of fibrous osteodystrophy which results from dietary imbalances in calcium and phosphorus.

Calcium and Phosphorus ratios

     Since the ion product(s) of total skeletal calcium and phosphorus in most vertebrate species are in a ratio of approximately 2:1 it would appear reasonable that the available dietary ratio of these elements also should be in a range of 1:1 to 2:1. Simple stoichiometric chemistry predicts that an excess of either calcium or phosphorus will create an imbalance. In clinical practice, one usually finds diets containing gross excesses of phosphorus ion products. Muscle meats and many vegetables contain extremely low quantities of available calcium but are well endowed with excessive phosphorus.

     When gross imbalances in the calcium: phosphorus ratio exist, the relatively insoluble salt, calcium phosphate (which is minimally absorbed from the gut), is favoured within the intestine. Excess phosphate ion can be absorbed thus resulting in hyperphosphatemia. The parathyroid glands are stimulated to secrete parathormone, thus inducing the leaching of calcium from the hydroxyapatite crystals in the mature bone matrix. As reabsorption continues, the bone is weakened and, concomitantly, is partially replaced by fibrocollagenous connective tissue. Affected bones tend to be larger in diameter with irregular outlines and a characteristically spongy consistency. Radiographs demonstrate normal medullary cavities surrounded by massively expanded cortical bone of greatly diminished radiodensity. These bones are deformed easily, and pathological fractures of weight-bearing long bones and vertebrae are common sequelae to this disorder. Ingestion of excessive dietary calcium ion products (with respect to phosphorus) is possible, but very unusual. When it does occur, the parafollicular cells or "C" cells of the thyroid gland(s) and ultimobranchial bodies are stimulated to secrete a hormone like substance, calcitonin, which acts to inhibit calcium ion resorption from hyroxyapatite, i.e.., it is antagonistic to the action of parathormone and, thus, reduces plasma calcium levels.

     Plasma Ca and P levels can aid diagnosis and, more importantly, guide therapy. Early cases of MBD may or may not have a normal Ca and P levels, but as MBD becomes more apparent, plasma Ca levels generally decrease (often <8.5 mg/dl) and plasma P levels generally increase. An inverse Ca:P ratio is strong evidence of MBD. Symptomatic iguanas can also have a normal plasma ca and P levels. Keep in mind that because Ca is protein-bound, hypoproteinemia can contribute to an apparent hypocalcemia. Alkaline phosphatase is generally not dramatically elevated, and the significance of this enzyme in reptiles is unknown.

     Hypocalcemic metabolic bone disease: Symptoms: intermittent fine muscle tremors, often first apparent in the digits, large muscles of the limbs and tail base, the tremors become increasingly more severe and frequent, especially with activity. If not corrected the fasciculations can progress to seizures and or tetany. ..."

     Too much phosphorus in the blood can be caused by quite a few factors. The biggest factors being the animals diet, and the phosphorus content in each food item; hypervitaminousis D; Inadequate access to direct sunlight or artificial UVB lighting; and not being kept at the proper temperatures since proper temperatures will help the animal digest the food that it eats properly and thus absorb most of the nutrients in it's diet.

     In addition to the typical causes of MBD (lack of Ca, vitamin D, and UV light or excess P) many conditions can cause similar symptoms such as egg production; thiamine (Vitamin B1), vitamin E or selenium deficiencies, septicemia, trauma, neoplasia, renal or hepatic disease, heavy parasite burdens and insecticide or heavy metal toxicity.

     Two frequent causes of hypocalcemia are worth mentioning. The first is egg or follicle development in female iguanas. Gravid females tend to have distended abdomens and have been anorectic for days to weeks. The second is renal failure. A common cause, hypervitaminousis D, is thought to arise from over dosages of multivitamins and fortified mammalian rations, such as dog, cat or primate chow. In such cases, uric acid is often not elevated but P levels are. Kidney enlargement may be palpable cloacally or anterodorsal to the pelvis. Dyschezia, and less commonly, stranggiuria may be present from kidney enlargement within the pelvis. Most of these patients are depressed and eating less but not obviously polydipsic.

Blood Calcium levels

     The plasma calcium concentration usually is elevated in fibrous osteodystrophy until late in the course of the disease, at which time it may be so low that hypocalcemic muscle tremors, tetany or asthenia occur. Death from cardiac failure usually ensues when the plasma calcium reaches such precipitous levels. Even the novice herpetologist usually would have noted the gross abnormal skeletal lesions by this time.

Therapeutic Calcium

     Interestingly, even advanced cases of fibrous osteodystrophy often yield to therapy. Crocodilians and lizards, particularly herbivorous iguanas, respond well to oral and injectable calcium salts such as calcium lactate and calcium gluconate. Oral calcium carbonate is useful also. Vitamin D3 also should be provided to ensure adequate uptake from the intestinal mucosa (only while the animal is affected by hypocalcemia). The diet must be corrected to restore the intake of available calcium and phosphorus to an appropriate physiological ratio."

In Laymans' terms.....

     In other words the various DMV's quoted in this article are saying that MBD is made up of a number of disorders. One of the most common of these disorders is an improper balance of calcium and phosphorus in the diet resulting in hyper or hypocalcemia. Mbd can affect the internal organs as well as the bones.

     When there is an imbalance of calcium in the diet (hypocalcemia or hypercalcemia) bones become weak and spongy. The affected bones will also enlarge, and have irregular outlines i.e. bumps and swellings. These bones will deform easily and may also fracture easily. As the calcium levels in the blood drop muscle tremors, tetany, and or asthenia occur. When the calcium level becomes critically low death from cardiac failure may occur.

Vitamin D3, UVB, and Calcium

     Vitamin D3 (derived from exposure to ultraviolet B), calcium (dietary and matter recycled from the bone matrix) and phosphorus (dietary) interact together to perform a number of functions besides bone growth and maintenance, including muscle contractions and blood coagulation (Wright, 1993). The result is a well-functioning system, with calcium restored to and, in the case of growing animals, added to the bone matrix.

     Too much phosphorus can throw this process off, as can too much or too little vitamin D3 or too little access to ultraviolet B wavelengths. As the dangers of calcium deficiency become more widely known, there is increased risk that pet owners may add too much calcium to their reptile's diet. This results in hypercalcemia, a condition as fraught with peril as is hypocalcemia.

     It is possible to have a condition where there is too much calcium in the blood stream, this condition is known as hypercalcemia:

     Control of serum or plasma calcium levels is mediated by parathormone, calcitonin, and vitamin D. Normal serum calcium values for reptiles vary among the species, but generally range between 8 and 20 mg/dl. ... Protein, calcium, and magnesium blood values may increase prior to egg production in female reptiles. Blood calcium values increase significantly (two to four-fold) in female reptiles exhibiting active folliculogenesis, where mobilization of calcium from bone results from increased estrogen activity.

     Latrogenic hypercalcemia (i.e. serum calcium values > 40 mg/dl) is a common disorder of captive reptiles and results from excessive dietary calcium and vitamin D. Other less common causes or considerations for a hypercalcemia include primary hyperparathyroidism, pseudo hyperparathyroidism, and osteolytic bone lesions. Hypocalcemia would be expected with nutritional imbalance of calcium, phosphorus and vitamin D.

     In other words- hypercalcemia- if it's going to occur, usually results from too much calcium and vitamin D in the diet, or occurs in a female in a follicular stage of egg development. Hormonal or dietary causes mainly.

If you think your reptile is calcium deficient Here are some questions to ask yourself:

Do you have a UVB florescent light over the reptile?

     UVB florescent lights sold in pet stores and some health food stores such as reptisun, vitalight or iguana 5.0 produce UVB light in the 290 to 310 nm range. If your reptile is diurnal (active during the day, such as a water dragon or an iguana) you need this kind of lighting to ensure your animals health. You need this kind of light to help your reptile use the calcium in the diet properly. UVB lighting from an artificial source such as one of the tubes mentioned above, or from direct unfiltered sunlight helps the reptile make vitamin D2 in it's skin, which in turn is converted to an active form of vitamin D3. This self created vitamin D3 helps the animal use the calcium in it's diet efficiently.

     The tube should be set up so that there is NO glass or plastic between the light and the reptile as these materials block the vital UVB rays. The light should also be set up so that it is no more than 10 or 12 inches above the reptile as it is most effective at that range. UVB florescent tubes only produce UVB light for 6 to 12 months. Even though they still produce UVB light, the UVB becomes greatly reduced with use as it nears a year of age. I recommend replacing UVB florescent lights every 8 to 12 months.

     As always, if outside temperatures permit, getting a healthy reptile, or one that might have calcium deficiency outdoors for some exposure to sunlight is one of the best forms of therapy for the animal. If you take your reptile outdoors it should either be held securely in your hands, or in a screened cage. Never leave a reptile outdoors in a glass tank as it could easily overheat in the sun. Any outdoor cages used for reptiles should have good ventilation and a shady area so that the animal might have a chance to thermoregulate if it does become too hot. The shaded area might also make the reptile feel more secure when outdoors. 15 to 30 minutes of sun once or twice a week is recommended for a healthy animal, daily exposure would be best for one suffering from known or suspected calcium deficiency.

      If the temperatures are too cool in your area to actually take the animal outdoors for some sunlight, you might try to set up a basking area in front of a sheltered (from wind) screened window. Place a heating pad in the window sill, and set up a basking lamp to warm the area and set your reptile in front of the window in the sunlight for a short while. Please make sure the window screen is secure. Metal screens are best.

What kind of supplements are you offering?

     What kind of vitamin and mineral supplements do you use, how often do you offer them, and do they say they are phosphorus FREE or that they have added phosphorus?

     Many species of reptiles are fed insects as the sole or as an extremely high percentage of their diets in captivity. IF the animals diet consists of a high percentage of insects, which are already high in phosphorus, it is extremely important to make sure that any vitamin or calcium supplement that you are giving your animal is PHOSPHORUS FREE. Why add to the problem?

     It would be much better if all the foods we could offer our animals were higher in calcium than they are in phosphorus, but unfortunately it's usually the other way around with the food item often having twice the amount of phosphorus to calcium.

     When I recommend supplementation, I recommend calcium (Phosphorus FREE of course) either daily or every second day, and vitamin supplements no more than once a week. I've never recommended giving vitamins on a more frequent basis.

     If the reptile keeper is feeding a well balanced diet, providing UVB lighting or direct sunlight, proper temps, calcium supplementation daily or every second day, and vitamin supplements NO MORE than once a week then the phosphorus level can not possibly be raised due to vitamin supplementation alone.

     If however someone is giving vitamins (especially one with added vitamin D3 and phosphorus) on a daily or every second day basis, then yes, it's possible that the blood phosphorus level will be too high, particularly if combined with a mainly insect diet.

Are you using a vitamin that has vitamin D3 in it or Vitamin D3 drops (Solar Drops)?

      Vitamin D3 is a fat soluble vitamin. It is made naturally in the skin of most animals and it helps the animal use and digest the calcium in it's diet properly. An animal getting a well balanced diet, and UVB light or direct sunlight should not need vitamin D3 supplements in it's diet. It will be making enough of this important vitamin on it's own.

     If it is getting vitamin D3 supplements or too much vitamin D3 supplementation the D3, being fat soluble, can build up to toxic levels in the animals system.

     Hypervitaminousis D produces soft tissue calcification. Vitamin D intoxication has followed ingestion of rodenticides containing cholecalciferol. Clinical signs in mammals are depression, anorexia, polyuria/polydipsia (frequent urination/excessive thirst), and weight loss. Treatment regimens for reptiles have not been tested by controlled clinical trials; currently, treatment should follow guidelines for other species, which often include glucocorticoids and calcitonin.

      A veterinarian, Dr. Keith Benson, who was on my Turtle-l mailing list said regarding Vitamin D3 or Solar drops: "What I find interesting is that the dose is given irrespective of the size of the animal. Surely this will result in some overdosing and under dosing. D3 is considered (and this is based on very little, if any, data) safe at about 100 IU/kg/week in reptiles. The material in the bottle claims to have 1,500 IU per ml, and one drop averages about 1/20 of an ml. That would be like giving 750 IU - theoretically enough to treat 7.5 kilograms of reptile. Now, I realize that the dose might be higher than the one above, or lower - no one knows, even the folks that make this product ;) Consider how concentrated this material is, then consider the damage that overdosing vitamin D can do (renal disease, soft tissue mineralization etc.) and I would say that until more data regarding the metabolism of this material in reptiles is know I would choose not to use it."

What are your cage temps?

     This article was written with a water dragon or iguana in mind, so please check what the proper day and night time temperatures are for your reptile if it is not a water dragon or iguana.

     For a water dragon- Day time temps should be between 84 and 88 F (28.9 C - 31.1 C), with a basking area of 95 F (34.99 C), and night time temps of 75 and 80 F (23.9 C - 26.7 C).

     For an iguana - The day time temperature range should be between 80 F ( 26.6 C) and 88 F (31.1 C), with a basking spot of 95 F (34.9 C). Night time temperature should be between 75 F (23.8 C) and 80 F (26.6 C)

     If the cage temperatures are too low your reptile might not be digesting his or her food properly and not using the calcium in the food properly either. If the animal appears ill or is known to be suffering from calcium deficiency you should probably keep the animal at as close to day time temps 24 hours a day as possible until she or he begins to recover. The extra heat at night will help boost the metabolism and immune system.

What are you feeding your reptile?

      An iguana or other vegetarian type of reptile should eat a purely herbivorous diet. An example of such a diet can be found at http://www.triciaswaterdragon.com/salad.htm The diet should include a variety of food items so as to offer the best assortment of nutrients to the animal.

     A water dragon is an omnivore - eating a large variety of insects, whole prey food items (feeder fish and pinky mice), and occasionally some fruit or vegetation. Once more- the better the variety of food items offered the more variety in the assortment of available nutrients for the dragon (or other omnivorous or carnivorous reptile). Please see http://www.triciaswaterdragon.com/diet.htm and http://www.triciaswaterdragon.com/wholeprey.htm for diet suggestions for the omnivorous and carnivorous reptile.

Is the reptile eating at all? Is it active, alert, and have good colouration?

      It's always a good sign if the animal is alert, an even better sign if it's active and eating on it's own, no matter what the suspected health problem might be. Reptiles rarely show that they are ill until they are extremely ill. By that time there is little time to do something to help them. Any behaviour changes in your reptile should always be noted as a possible sign of illness - from lessened appetite down to lessened activity, lethargy and poor colour.

     If your reptile has reached an adult size it might be of breeding age. Female reptiles can develop eggs even if they have never mated before- the eggs just won't be fertile. Please keep this in mind if your reptile is of adult size/age and begins to not eat well and exhibit signs of calcium deficiency. It could be gravid. Egg development uses up a lot of calcium .... and many female reptiles do develop calcium deficiencies at this time.

     If your reptile has developed calcium deficiency there has to be something wrong with the husbandry (unless there is a hormonal cause). Lighting, diet and proper temperatures all go hand in hand towards maintaining the health and proper calcium balance in our reptiles ... if something is off slightly such as too low temps it won't matter how well you are doing the other things, this could be enough to throw everything off for the animal. So please check out everything that I've mentioned above as something is probably off.

If you suspect that your reptile has MBD:

      It is very important that the reptile have proper medical attention. Diagnostic tests such as drawing blood to test the calcium and phosphorus blood levels and ratio or taking an Xray to check for possible fractures, eggs and to check the bone density can all help determine if the animal has a calcium deficiency and how severe the problem might be.

     A veterinarian will most likely send you home with liquid calcium and instructions for proper dosage. The dosage for liquid calcium is 1 mg/kg twice a day. Of course if the animal has fractures those will need to be dealt with as well and the animal might have splints or a cast applied to a limb, or even screws surgically placed into the bones if the animal has a very bad fracture. If the case of calcium deficiency is severe the vet might also give the animal injections of calcium, and or calcitonin.

     It is unlikely that you will be able to determine the severity of the calcium deficiency on your own. Nor will you have access to injectable calcium or calcitonin if your reptile needs it. I strongly suggest taking your reptile to a reptile veterinarian if you suspect calcium deficiency. There are links below that will help you find a reptile vet in your area.

     Along with proper medical care, it is important that you do check that the cage temps are correct, that you have the UVB florescent tube set up properly, that you try to keep the animal closer to day time temperatures at night so as to boost the immune system and metabolism, provide a proper diet with calcium carbonate powder supplementation, and that if the outside temperatures are 70 F or higher that you try to get the reptiles outside once or twice a week (daily if possible) for 15 to 30 minutes at a time for exposure to unfiltered sunlight. You can also set up the animal in front of a secure screened window for exposure to sunlight if it's too cool to take the reptile outside.

Reptile Veterinarian Links

• USA and International Vet listings
• HerpVet Connection
• Canadian Reptile Vets
• Association of Reptilian and Amphibian Veterinarians (ARAV) Click on members and see if your vet is listed
• And if you are taking a vacation- The Herpsitters list

References

1. Dr. Doug Mader DMV- Reptile Medicine and Surgery, WB Saunders Company, copyright 1996 ISBN 0-7216-5208-5
2. Frye, F.L. (1992) Reptile Care: An Atlas of Diseases and Treatments. Malabar FL: Krieger Publishing.
3. "Reptile Rehabilitation", In, The Biology, Husbandry and Health Care of Reptiles and Amphibians, Vol I., Reptiles. Lowell Ackerman (ed.) In press. (c) 1995

Water Dragon Books

Green Water Dragons, Sailfin Lizards and Basilisks (General Care and Maintenance of Series) by Philippe De Vosjoli

      Basic but detailed information about the care, diet, and health of green water dragons, sailfin lizards and basilisks.

Anoles, Basilisks and Water Dragons : A Complete Pet Care Manual (More Complete Pet Owner's Manuals) by Richard D. Bartlett, Patricia P. Bartlett (Contributor)

     Discussion of the general care of many species of anole, basilisks and water dragons. Excellent information regarding enclosures, cage building, and insect care and breeding.

Eat This Bug : A Guide to Invertebrate Live Foods for Reptiles and Amphibians by Lynn Davis

      This book is a guide for owners of reptiles and amphibians who feed insects and other live foods to their pets. Advice is offered for selecting , ordering and raising your own supply of live invertebrate foods. More than a dozen species of live foods are discussed. The book includes instructions on keeping cultures of insects, and recipes & diets for insects.