© squirrelrehabilitation.com, 2011 Diseases Metabolic Bone Disease                (Hypocalcemia) Definition: Metabolic Bone Disease has many names (Wissman; Kaplan; et.al.), but most rehabilitators know it as “Metabolic Bone Disease” or simply “MBD.”   It is a disorder caused by calcium deficiency which causes many detrimental effects on the animal suffering from it--up to and including death. Etiology/Causes:  MBD can have many causes, such as disease of the liver, kidneys, intestines, thyroid gland, or parathyroid gland--but the most common cause in rehab or with captive squirrels is a lack of proper diet and general husbandry.  Most susceptible to MBD are young squirrels (particularly after a few weeks after weaning), captive squirrels, and squirrels in long-term rehab.  If the disease is dietary, it is caused by feeding a diet that is too low in calcium and too high in phosphorus and not providing the animal with a source of vitamin D (preferably regular exposure to UVA and UVB light, particularly the sun).  Much has been written about MBD and hypocalcemia (see references below for good discussions), so there is no need to repeat here.  Unfortunately, by the time most begin noticing symptoms of MBD in squirrels, the disease has progressed to a stage very difficult to cure.  The best defense against MBD is prevention.  Symptoms: 1.  Lethargic/reluctance to move because of pain 2.  Weakened and/or distorted and/or malformed limbs/tail/spine 3.  Swollen joints 4.  Facial deformities (including malocclusion) 5.  Lack of appetite/weight loss 6.  Retarded growth in young 7.  Cataracts in young animals (Wissman) 8.  Involuntary twitching of muscles under the skin 9.  Twitching of a toes, legs, tail 10.Tremors/spasms 11. Seizures 12. Paralysis Diagnosis: 1.  Know the history of the squirrel, particularly diet.  2,  Radiographs may show weakened bones and possibly fractures. 3.  Blood tests for decreased serum calcium levels, increased phosphorus levels, and increased      phosphatase levels. (NOTE:  Blood tests aren’t always an accurate indicator of MBD because the body will      resorb the calcium in bone for as long as it can to maintain correct serum calcium levels). Treatment: Medical 1.  If severe (convulsions/spasms/seizures), the squirrel should be immediately given intravenous calcium      gluconate at 1-1.5 mL/kg slowly over a 10-minute period (Merck).  The Exotic Animal Formulary suggests      100mg/kg calcium gluconate either IP or IM (Carpenter).   Plumb’s Veterinary Drug Handbook suggests      94-140 mg/kg administered slowly IV (Plumb).  Consult your veterinarian!       Once the life-threatening signs of hypocalcemia subside, the squirrels should be given  a “slow continuous      infusion (10% calcium gluconate, 2.5 mL/kg every 6-8 hr)” (Merck).  Blood serum calcium levels should be      tested periodically.       (Note: Margaret Wissman, DVM, reports that calcitonin-salmon (Calcimar), a synthetic form of calcitonin      and a drug given to post-menopausal women, “works well to treat the effects of, and even works to reverse,      MBD in all the animals this author has used it on.”  She cautions, however, that it should not be administered      until the calcium levels in the animal are stabilized and normal (Wissman)). 2.  Vitamin D injections may also be in order, but consult a veterinarian as vitamin D can be toxic!  The Exotic       Animal Formulary suggests 200-400 IU/kg for all rodent species (Carpenter). 3.  Once stabilized, the squirrel should be given calcium glubionate at 1 ml/kg orally every twelve hours “for      several months“ (Wissman). 4.  If immediate veterinary care is not available, many rehabilitators suggest giving either calcium carbonate      (what many antacids such as Tums are composed of) or calcium citrate orally.  The minimum daily      requirement of calcium for laboratory rats is 75 mg/day (Nutrient).  For a squirrel suffering from MBD, it is      assumed that this minimum requirement can be increased several times--perhaps 400 to 600 mg/day.       But if Vitamin D is supplemented, use caution, as hypercalcemia may result.  Supportive 1.  THE DIET MUST BE CHANGED!  The diet should be carefully monitored to achieve a balanced 2:1      calcium to phosphorus ratio. 2.  Keep the squirrel in a relatively small cage so that it doesn’t break brittle bones. 3.  Ensure that the squirrel gets adequate amounts of UVA and UVB exposure, preferably from the sun. 4.  Keep high-calcium “toys” and “treats” in the cage at all times for the squirrel to chew on--cuttlebone, bones      of any kind, bird or rodent mineral blocks. References: Carpenter, James W.  Exotic Animal Formulary, Third Edition. Kaplan, Melissa.  “Calcium Metabolism and Metabolic Bone Disease.”  www.anapsid.org/mbd2.html Merck Veterinary Manual, 10th ed. Nutrient Requirements of Laboratory Animals.  National Research Council.  Fourth Revised Edition, 1995. Plumb, Donald C.  Plumb’s Veterinary Drug Handbook, 6th edition. Tabor’s Cyclopedic Medical Dictionary, 20th ed. Wissman, Margaret A., DMV.  “Metabolic Bone Disease in Exotic Pets.”  www.exoticpetvet.net/dvms/mbd2.html Type:  Metabolic