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| − | ===Rickets=== | + | ===[[Rickets]]=== |
| − | [[Image:Rickets in dog.jpg|right|thumb|100px|<small><center>Rickets in dog (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] | |
| − | *Essentially the same disease as osteomalacia
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| − | *Caused by Vitamin D and phosphorus deficiency
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| − | *In young animals
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| − | *Failure of:
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| − | **Mineralisation of osteoid at sites of membranous growth
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| − | **Cartilage vascularisation and mineralisation at sites of endochondral ossification
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| − | *Osteoid and catilage build up at those sites
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| − | *Histologically:
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| − | **Lines of hypertrophic cartilage cells are lenghtened and disorganised
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| − | **Ossification at metaphysis is poor
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| − | **Persisting osteoid and cartilage -> shaft modelling failure
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| − | **Thuckened physes due to normal chondrocyte proliferation but defective removal
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| − | *Ends of bones enlarge -> club-like thickening of metaphysis + compression of epiphysis
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| − | **Most affected:
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| − | ***Proximal humerus
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| − | ***Distal radius
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| − | ***Ulna
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| − | ***Ribs
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| − | ****Enlargement of costochondral junction - called 'rachitic rosary'
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| − | *Weight bearing leads to:
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| − | **Thickening of the physis and
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| − | **Flaring of the excess matrix at the metaphysis
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| − | *Histological lesions heal whn diet corected
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| − | *Minor deformities correct but major deformities remain
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| − | *Occurs after weaning because:
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| − | **''In utero'' and in milk - adeqaute nutrients obtained at expense of dam
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| − | *In Foals
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| − | **Rare - long nursing period and relatively slow rate of growth
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| − | *In Calves and lambs
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| − | **When diet deficeint of phosphorus and poor exposure to sunlight
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| − | *In Puppies, Kittens and Piglets
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| − | **Rapid growth, weaned early -> fulminating rickets if poor exposure to sunlight and lack of vitamin D in diet
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| − | [[Category:Bones - Metabolic Pathology]]
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