Metabolic Bone Diseases

• Metabolic Bone Diseases

  • Rickets
  • Osteomalacia
  • Osteoporosis
  • Fibrous osteodystrophy
• Metabolic Bone Diseases

  • Systemic bone disorders of various etiologies including dietary, hormonal and toxic
  • An imbalance between bone formation and resorption in the normal remodeling process of bones
• Most common toxic osteodystrophies

  • Hypervitaminosis A
  • Hypervitaminosis D
  • Osteofluorosis
  • Lead poisoning
• Rickets

  • Disease of the developing skeleton characterized by abnormal endochondral ossification and defective bone formation
  • Deformation of the forelegs and enlarged carpal joints
  • Due to softening of bone
  • Characterized by an abnormal widening of the "growth cartilage" (growth plates), bone softening, deformations, and swelling of the cartilagineous joints
  • Chondrocytes proliferate but do not mature and degenerate properly, thus cartilage is retained and accumulates in bones
• Osteomalacia


  • A disease in adult animals associated with disruption of normal bone remodeling
  • Deformity of the forelegs with lateral deviation of the radius and ulna
  • Bone softening and weight bearing
• Osteoporosis


  • Also referred to as bone atrophy
  • A condition in which the bones of an animal become fragile and brittle (but not soft like rickets, osteomalacia or osteodystrophia fibrosa)
  • Due to lack of calcium and vitamins
  • Due to certain hormonal changes
  • Referred as low bone mass and strength in the bones
  • Negative balance between formation and resorption of bone
  • There is little bone, but what bone there is, is normal
• Fibrous Osteodystrophy


  • Characterized by the removal of the mineral from the skeleton and replaced by immature fibrous connective tissue
  • Generalized throughout the skeleton but is accentuated in local areas such as the cancellous bone of the skull
  • The increased PTH levels also inhibit the renal tubular resorption of phosphorus
• Hypervitaminosis A


  • Caused by prolonged excessive intake of vitamin A
• Hypervitaminosis D


  • Rare but potentially serious condition that occurs with excessive amounts of vitamin D
• Fluorosis


  • Chronic condition caused by excessive intake of fluorine compounds
  • Marked by mottling of the teeth
  • If severe→calcifications of ligaments
• Lead Poisoning


  • Characterized by neurologic disturbances, gastrointestinal upset, hematologic abnormalities, immunosuppression, infertility and renal disease
  • Influenced by dose and duration of lead exposure
  • Symptoms→muscle twitches, paralysis of the tongue, circling, and 'star-gazing'