ISSN 2398-2969      

Osteoporosis

Clapis

Introduction

  • Osteoporosis is a skeletal/metabolic disease characterized by bone mass loss and micro-architectural deterioration of the whole skeletal system, which augments skeletal fragility and fracture prevalence.
  • Cause: ovariectomy/ovariohysterectomy, glucocorticoid use, lack of UV light exposure, calcium-deficient diet, secondary hyperparathyroidism.
  • Signs: dental disease, fractures.
  • Diagnosis: radiology, low blood calcium levels, increase blood PTH (parathormone) levels.
  • Treatment: anabolic drugs, calcium supplements, exposure to UV light.
  • Prognosis: worsens as severity increases.
Print off the Owner factsheet on Osteoporosis to give to your clients.
 

Pathogenesis

Etiology

  • Osteoporosis affects more than 200 million people, and rabbits have been used as a model animal for the investigation of this disease.
  • Glucocorticoids Therapeutics: glucocorticoids induce a loss in cortical and trabecular bone, increase osteoclastic resorption, and decrease new bone formation:
    • Glucocorticoids can produce signs of osteoporosis after just 4 weeks of use.
    • The higher the dose, the more likely to develop osteoporosis.
    • The effects of glucocorticoids are cumulative.
  • Ovariectomy/ovariohysterectomy Ovariohysterectomy causes osteoporosis due to associated estrogen deficiency:
    • Estrogen deficiency increases osteoclastogenesis and reduces intestinal and renal calcium absorption.
    • By 13 weeks after surgery a 10% bone mass loss is seen in lumbar vertebrae.
    • At 17 weeks after surgery the reduction of bone mineral density is 20% in the proximal tibia and 10% in the femur.
    • The negative effects of surgery on bones increase with time.
  • The prolonged use of GnRH agonists, eg deslorelin, suppresses estrogen production and can have similar effects on bone density.
  • Low calcium diets Nutrition: dietary requirements and lack of UV-light exposure are also involved in osteoporosis and other metabolic bone diseases. 
  • Other drugs can also contribute to osteoporosis, such as heparin.
  • The effects of all these different causes may be combined and may be cumulative. The combination of ovariectomy/ovariohysterectomy and glucocorticoid use (particularly at moderate and high doses) is commonly used in research to generate models of osteoporosis in rabbits.

Predisposing factors

General

  • Captivity.
  • Osteoporosis and other metabolic bone diseases are rarely seen in wild rabbits.

Specific

  • Glucocorticoid use.
  • Ovarian removal/suppression in females, eg ovariectomy, use of deslorelin.
  • Lack of access to UV-light exposure.
  • Low calcium diets.

Pathophysiology

  • Osteoporosis produces a demineralization of the jaw, particularly affecting the perialveolar area. This enhances tooth movement and the development of malocclusion Dental malocclusion/overgrowth. Malocclusion leads to lack of dental wear and elongation of dental roots, which facilitates the development of perialveolar abscesses:
    • Elongated roots and abscesses easily perforate osteoporotic jaw and skull bones.
    • Demineralization occurs earlier in the jaw than in other bones. 
  • Loss of bone density in other bones predisposes rabbits to fractures, such as lumbar fractures Spinal injury .
  • Osteoporosis prevents proper healing of fractured bones.

Timecourse

  • Osteoporosis is a progressive disease when causes are not addressed. The cumulative effects of some actions (eg lack of estrogens due to ovariectomy, long-term treatment with glucocorticoids) and the combination of some causes (eg lack of UV-light access in ovariectomized females) may increase prevalence and severity of the disease as the animal ages.
  • Bone changes compatible with osteoporosis can be evident at 4-6 months of ovariectomy, as a result of a reduction of estrogens after surgery and the chronic effects of this estrogen deficiency in calcium and bone metabolism.

Epidemiology

  • Increase prevalence and severity as rabbits age.

Diagnosis

This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Baofeng L, Zhi Y, Bei C et al (2010) Characterization of a rabbit osteoporosis model induced by ovariectomy and glucocorticoid. Acta Orthopaedica 81 (3), 396-401 PubMed.
  • Bellido M, Lugo L, Castañeda S et al (2010) PTH increases jaw mineral density in a rabbit model of osteoporosis. J Dent Res 89 (4), 360-365 PubMed.
  • Castañeda S, Calvo E, Largo R et al (2008) Characterization of a new experimental model of osteoporosis in rabbits. J Bone Min Metab 26 (1), 53-59 PubMed.
  • Harcourt-Brown F M & Baker S J (2001) Parathyroid hormone, haematological and biochemical parameters in relation to dental disease and husbandry in rabbits. J Small Anim Pract 42 (3), 130-136 PubMed.
  • Little D G, Cornell M S, Briody J et al (2001) Intravenous pamidronate reduces osteoporosis and improves formation of the regenerate during distraction osteogenesis. J Bone Joint Surg (Br) 83 (7), 1069-1074 PubMed.
  • Wanderman N R, Mallet C, Giambini H et al (2018) An ovariectomy-induced rabbit osteoporotic model: a new perspective. Asian Spine J 12 (1), 12-17 PubMed.
  • Wen X X, Xu C, Wang F Q et al (2015) Temporal changes of microarchitectural and mechanical parameters of cancellous bone in the osteoporotic rabbit. Biomed Res Int 2015, 1-11 PubMed.

Other sources of information

  • Varga M (2014) Textbook of Rabbit Medicine. 2nd edn. Butterworth-Heinemann, UK. pp 494.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code