Nutritional bone disease

Question 1

Presentation - bone disease

Answer 1

• young (can be adult)
• deviation of limbs, poor posture, weakness
• axial skeleton as well as appendicular
• dietary problems
• comparison with littermates
• pathological fractures
• generalised disease

Question 2

Actions - PTH

Answer 2

• increase Ca absorption
• decrease Ca excretion
• both increase plasma calcium

Question 3

Outline secondary nutritional hyperparathyroidsim

Answer 3

• low dietary Ca drives:
• high PTH levels
• serum Ca often protected
• bones are malformed or poorly formed
• usually young growing animal (v. unusual for dietary Ca to be low in adults)

Question 4

Define pathological fracture

Answer 4

when an underlying problem in bone precipitates a fracture which wouldn’t otherwise occur

Question 5

Outline vitamin D deficiency

Answer 5

• v rare in animals
• juvenile –> rickets
• adults –> osteopaenia

Question 6

Outline secondary renal hyperparathyroidism

Answer 6

• Chronic renal failure (adult normally)
• decreased vitamin D activation (kidney)
• lowered phosphate excretion (phosphate binds to Ca, serum Ca is lowered)
• increased PTH drive and effects on bones
• mandible is classic place to see this

Question 7

What animals does secondary nutritional hyperparathyroidism affect?

Answer 7

most domestic dogs/cats are fed well balanced commercial food, usually a problem for inexperienced exotics owners

Question 8

What is metabolic bone disease (MBD) of reptiles and chelonians?

Answer 8

• called ‘metabolic’ but aetiology unknwon
• green iguanas
• low dietary availability of Ca
• decreased activation or availability of vitamin D3

Question 9

MBD - hx

Answer 9

• lethargy
• inability to lift trunk/tail
• pliant mandible
• abnormal posture
• wt loss/ decreased appetite
• check diet
• male/female going to lay eggs

Question 10

Clinical exam - MBD

Answer 10

• activity
• movement/ lamaness
• joint/limb swelling
• mm tone and atrophy

Question 11

Radiography - MBD

Answer 11

• joints, limbs and spine
• egg binding
• spontaneous fractures

Question 12

Where to take a blood sample -reptiles

Answer 12

tail vein (look for low Ca in MBD)

Question 13

Ddx - MBD

Answer 13

• gout
• septic arthritis
• spinal spondylosis

Question 14

Confirmation of MBD

Answer 14

• swollen bones
• poor density
• misshapen
• pliant mandibles
• lethargy
• unable to lift body off ground
• path. fractures
• low serum Ca

Question 15

Tx - MBD

Answer 15

• Ca gluconate, dietary adjustment (2% Ca diet)
• UV light, and/or direct sunlight (not through glass)
• monitor blood Ca

Question 16

Phosphates and Ca level in meat

Answer 16

• high phosphates

- low calcium

Question 17

What other diseases are also called ‘metabolic’ bone disease

Answer 17

• calcinosis circumscripta
• craniomandibular osteopathy
• (metaphyseal osteopathy)/ hypertrophic osteodystrophy (HOD)
• panosteitis
• hypertrophy pulmonary osteoarthropathy (Maries’ disease)

Question 18

What is calcinosis circumscripta?

Answer 18

extra Ca deposti around joint possibly d/t trauma?

Question 19

What is craniomandibular osteopathy?

Answer 19

possibly immune-mediated

Question 20

What is Metaphyseal osteopathy?

Answer 20

= better called hypertrophic osteodystrophy (HOD)

• provoked by distemper
• note the ‘extra’ physeal line which is in fact bone necrosis
• animal is often very febrile with this condition

Question 21

What is panosteitis?

Answer 21

• young growing dog
• unknown aetiology
• self-resolving condition
• endosteitis seen

Question 22

What is hypertrophic pulmonary oseoarthropathy?

Answer 22

= Maries’ disease in humans

• perisoteal activation in distal limbs
• usually related to thoracic/ abdominal tumour
• tumour produces growth factors leads to this condition