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Kidney Failure/
Metabolic Bone Disease/
Vitamin D Supplements


Kidney Failure due to over supplementing vitamins?

      One of the members of the water dragon mailing list wrote in recently to tell us that his lizard was very ill.

      "The vet said he has kidney failure. This occurred because the phosphorus level was above the calcium level. The vet said I might be giving him too much vitamin and calcium supplements. He was concerned about the vitamin D intake and said to dust his food only once a week. To try and reverse the kidney failure (which is possible) He has me giving him Gatorade, malox, water, and an antibiotic. He said the treatment will take months to do but it should get better due to his young age (1 1/2 years I think)."

      Vitamin supplements should only be offered once a week. Calcium should be offered more frequently. Unfortunately over supplementing vitamins, particularly those with added phosphorus and vitamin D are not the only cause of this problem. Diets too high in phosphorus can cause this too happen as well, as well as many other factors which I will discuss in this article.

      The original correspondent was either told by his doctor, or simply believed that kidney failure is reversible. Well it's possible to some degree, but once the kidneys are damaged they do not recover well. :( This is a very serious ailment that generally results in a shortened lifespan for the animal.

      The correspondent didn't explain his doctors treatment regime further when asked about it. Why malox? And why antibiotics? Antibiotics can be very hard on the kidneys. I wonder if the doctor thought the kidney damage was the result of an infection?

      I will discuss high phosphorus levels caused by improper diets, over supplementation of vitamins, Metabolic bone disease, Vitamin D3, resulting in Kidney failure in this article. These topics might seem totally unrelated at first, but read on, as I believe they are all connected, and will come together by the time you finish reading this.

Causes of Too much phosphorus in the blood

      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.

      This is why when people write or speak with me, asking for assistance with their animals, I literally PREACH offering a well balanced varied diet, offering supplements, and providing UVB lighting or direct sunlight, and proper day and night temperatures for that animal. If one of these basics of care isn't done adequately problems such as calcium deficiency, and yes kidney disease, can develop.

      When an animal has high phosphorus levels in it's blood stream that usually means that the calcium levels are low. If a veterinarian finds high blood phosphorus levels in a reptile he or she might go on to take an x-ray of the animal to check it's bone density. The doctor might also check the uric acid, creatinine and BUN levels in the animals blood as well, however these last three tests would probably be inconclusive. I would worry that the animal might be suffering from Metabolic Bone Disease if the phosphorus levels were high.

Metabolic Bone Disease and Diet

      Dr. D. Mader, In his medical text "Reptile Medicine and Surgery" 1996, Saunders. Says:

      "Diets lacking bone are a common cause of MBD for carnivorous reptiles. For example, 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."

      "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. "

      "Clinical signs of MBD, Classic Metabolic bone disease: This discussion is derived primarily from observations of green iguanas with MBD; however other lizards develop similar signs. ... In iguanas 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."

      "Another common finding is a pliable mandible or maxillae. 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 iguanas often retain the rounded infantile skull shape of hatchlings because the skull fails to grow and lengthen."

      "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. ..."

      "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. ..."

      "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 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."

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.

Also are you using a vitamin that has vitamin D3 in it or Vitamin D3 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 make 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.

      Mader says: "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."

Kidney/ Renal failure:

Normal Kidney function:

      The kidneys are two bean shaped organs that filter the blood, excreting the end-products of body metabolism in the form of urates, and regulating the concentrations of hydrogen, sodium, potassium, phosphate and other ions in the extracellular fluid.

Endocrine functions:

      In response to renal ischemia the kidneys regulate blood pressure by the renin-angiotensin-aldosterone mechanisms. Additionally, when kidney cells become hypoxic they release an enzyme called renal erythropoietic factor, which stimulates the maturation of oxygen-bearing red blood cells in the bone marrow. The kidneys also are involved in the conversion of inactive vitamin D to the active form, which increases calcium absorption in the intestines and calcium uptake by the bones.

Kidney Failure

      Polydipsia (excessive thirst) and polyurea (excessive urination) are uncommon signs in reptiles. Chronic renal failure may cause these signs. Causes of renal failure include bacterial infection, granulomatous inflammation, and excessive use of aminoglycoside antibiotics.

      Kidney failure is defined as the inability of the kidney to excrete metabolites at normal plasma levels under normal loading, or inability to retain electrolytes when intake is normal; in the acute form, marked by uremia (excess of end-products in the blood) and usually by oliguria (diminished urate secretion) with hyperkalemia and pulmonary edema.

      Acute renal failure occurs suddenly often as the result of physical trauma, infection, inflammation, or exposure to toxic chemicals. Nephrotoxic agents include drugs such as penicillins, sulfonamides, aminoglycosides, and tetracyclines; radiographic iodine contrast materials, and heavy metals. These agents inflict damage on the renal tubules, causing tubular necrosis. Other causes of tubular ischemia include circulatory collapse, and severe dehydration.

      Chronic renal failure is the progressive loss of kidney function. The clinical course is described in four stages.

      First there is a decreased renal reserve, with diminishing renal function but without accumulation of the end-products of protein metabolism. The patient has no symptoms.

      In the second stage of renal insufficiency, the glomerular filtration rate is depressed and plasma chemistry begins to show abnormalities as waste products accumulate.

      Frank renal failure characterizes a period of steadily rising serum creatinine and blood urea nitrogen levels accompanying a drop in the glomerular filtration rate.

      Uremia is the fourth and final stage, in which the levels of protein end products continue to rise and all body systems are impaired.

      Causes of renal failure are many and can be roughly divided into three groups:

  • Those that directly affect the kidney by infection, inflammation, and upper urinary tract obstruction,
  • Those in which there is an obstruction of the lower urinary tract, and
  • Systemic diseases and toxicities.

Signs and symptoms of Kidney Failure

      Mader states: "In the beginning a lizard may present with vague symptoms of anorexia and lethargy in the absence of polyuria and polydipsia. The kidneys are usually enlarged and protrude anterior to the pelvic canal on palpation and radiographs. Serum BUN, creatinine, and uric acid levels are unrewarding in the assessment of renal function in lizards. The most consistent change in clinical pathology are the elevation of serum phosphorus levels and a calcium to phosphorus ratio of less than one. Affected lizards are usually mildly Hypocalcemic, but occasional individuals are profoundly hypercalcemic and sometimes exhibit widespread metastatic mineralization. Ultrasound, the examination of urine sediment for the presence of casts, and kidney biopsy may be used to further evaluate the kidneys. The etiology of this syndrome has not been scientifically documented but is thought to be related to the use of animal based protein sources in the diet such as dog food and monkey biscuits. the lack of exposure to unfiltered sunlight may also play a role. Treatment is often unrewarding, but it includes correction of the diet and environmental conditions, the use of phosphate binders, and diuresis with intravenous or introsseous fluids."

      "Diabetes mellitus has been reported in a handful of reptiles, none of which were successfully controlled with insulin therapy. Diabetes may be associated with overwhelming septicemia, pancreattis, and metabolic imbalances."

      Kidney failure seems to be quite common in Green Iguana's due to the fact that their keepers continue to feed them animal protein in their diets, and due to the fact that they often do not get enough fluids in their diet. :( Dehydration can severely impair the function of the kidneys. :( It is very important that many of the species of reptiles that we keep have the proper humidity levels if they are tropical animals, and access to clean water everyday, in order to aid the proper function of their kidneys.

      Antibiotics are very hard on the kidneys and it is important to make sure the reptile is getting an adequate supply of water and fluids while antibiotics are being administered. If the animal is going to be on antibiotics for an extended period of time it is a wise idea to provide subcutaneous fluid injections in conjunction with antibiotic administration.

      Improper administration of antibiotics such as giving an Intermuscular injection of antibiotics in the back legs or lower body area can cause the antibiotics to get to the renal system too quickly and can cause severe damage to the kidneys.

      A reptiles health may deteriorate very quickly when signs and symptoms of kidney failure present themselves. Signs include:

  • weight loss,
  • anorexia,
  • lethargy,
  • swollen or distended abdomen,
  • frequent drinking and
  • frequent urination.

      Symptoms of renal failure can come on suddenly, and overlap those of many other conditions, and the keeper might not even realize the true cause of the animals quickly failing health. When severe renal failure occurs the animal may exhibit altered behaviour:

  • acting increasingly lethargic;
  • loss of appetite;
  • rapid dehydration;
  • constipation;
  • thickened and yellowing urates;
  • reduced thermoregulation or complete failure to thermoregulate (as they get too weak to move);
  • increased sleep time;
  • extremely rapid weight loss (inconsistent with past periods of reduced or no food intake);
  • loss of muscle tone;
  • lack of deep pain responses;
  • and gross reduction in interactive (animal/animal and animal/human) responses.

      Treatment for kidney failure involves treating any underlying illnesses that might be causing the kidney failure, evaluation and correction of the diet, evaluation and correction of the animals housing such as temperature and lighting requirements, therapeutic administration of phosphate binders, and administration of fluids subcutaneously, Intravenously or intraosseous. The reptile may survive kidney failure but once there is some damage to the kidneys it is usually irreversible. An animal that had kidney failure in the past may be more susceptible in the future and care should be taken to prevent a recurrence.

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     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.

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      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.

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