Nutritional bone disease Flashcards
Presentation - bone disease
- 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
Actions - PTH
- increase Ca absorption
- decrease Ca excretion
- both increase plasma calcium
Outline secondary nutritional hyperparathyroidsim
- 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)
Define pathological fracture
when an underlying problem in bone precipitates a fracture which wouldn’t otherwise occur
Outline vitamin D deficiency
- v rare in animals
- juvenile –> rickets
- adults –> osteopaenia
Outline secondary renal hyperparathyroidism
- 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
What animals does secondary nutritional hyperparathyroidism affect?
most domestic dogs/cats are fed well balanced commercial food, usually a problem for inexperienced exotics owners
What is metabolic bone disease (MBD) of reptiles and chelonians?
- called ‘metabolic’ but aetiology unknwon
- green iguanas
- low dietary availability of Ca
- decreased activation or availability of vitamin D3
MBD - hx
- lethargy
- inability to lift trunk/tail
- pliant mandible
- abnormal posture
- wt loss/ decreased appetite
- check diet
- male/female going to lay eggs
Clinical exam - MBD
- activity
- movement/ lamaness
- joint/limb swelling
- mm tone and atrophy
Radiography - MBD
- joints, limbs and spine
- egg binding
- spontaneous fractures
Where to take a blood sample -reptiles
tail vein (look for low Ca in MBD)
Ddx - MBD
- gout
- septic arthritis
- spinal spondylosis
Confirmation of MBD
- swollen bones
- poor density
- misshapen
- pliant mandibles
- lethargy
- unable to lift body off ground
- path. fractures
- low serum Ca
Tx - MBD
- Ca gluconate, dietary adjustment (2% Ca diet)
- UV light, and/or direct sunlight (not through glass)
- monitor blood Ca
Phosphates and Ca level in meat
- high phosphates
- low calcium
What other diseases are also called ‘metabolic’ bone disease
- calcinosis circumscripta
- craniomandibular osteopathy
- (metaphyseal osteopathy)/ hypertrophic osteodystrophy (HOD)
- panosteitis
- hypertrophy pulmonary osteoarthropathy (Maries’ disease)
What is calcinosis circumscripta?
extra Ca deposti around joint possibly d/t trauma?
What is craniomandibular osteopathy?
possibly immune-mediated
What is Metaphyseal osteopathy?
= 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
What is panosteitis?
- young growing dog
- unknown aetiology
- self-resolving condition
- endosteitis seen
What is hypertrophic pulmonary oseoarthropathy?
= Maries’ disease in humans
- perisoteal activation in distal limbs
- usually related to thoracic/ abdominal tumour
- tumour produces growth factors leads to this condition
