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===Pituitary===
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#REDIRECT[[:Category:Bones - Metabolic Pathology]]
 
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*Growth hormone
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**Secreted by the anterior pituitary
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**Influences the size of the skeleton and soft tissue
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====[[Congenital Panhypopituitarism|Pituitary dwarfism]]====
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====Pituitary gigantism ([[Acromegaly]])====
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===Thyroid===
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*Thyroid hormones affect maturation of growth of cartilage
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====[[Hypothyroidism]]====
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====[[Hyperthyroidism]]====
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===[[Gonadal Effect on Bones]]===
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===Adrenal glands===
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*[[Hyperadrenocorticism]]
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===[[Hyperparathyroidism|Hyperparathyroidism]]===
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===[[Rickets]]===
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===[[Osteomalacia]]===
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===Hypovitaminosis A===
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*Vitamin A is essential for normal bone growth in foetus and neonates 
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*Hypovitaminosis from dietary deficiency of dam -> teratogenic in pigs and large cats
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*More commonly, deficiency in neonates (puppies, kittens, calves, piglets) on vitamin-deficient diets
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*Dietary deficiency -> failure of [[Bones - Anatomy & Physiology|osteoclastic remodelling]] resulting in bone overgrowth and nerve compression
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*Optic nerves particularly affected
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[[Category:Bones - Metabolic Pathology]]
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===Hypervitaminosis A===
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[[Image:Hypervitaminosis A.jpg|right|thumb|100px|<small><center>Hypervitaminosis A (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Main lesions:
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**Injury to growth cartilage -> [[Bones - Anatomy & Physiology|premature closure of growth plate]]
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**[[Bones Degenerative - Pathology#Osteoporosis (Atrophy)|Osteoporosis]]
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**'''Exostoses'''
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**[[Musculoskeletal Terminology - Pathology|Osteophyte]] formation in prolonged exposure
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*In cats fed bovine liver for prolonged periods
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**Rich in vitamin A in grazing animals
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**Vertebrae fuse with each other due to bone proliferation - '''cervical spondylosis''' ('''ankylosing exostosis''' of the vertebral column), especially in the neck
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*Can also be teratogenic, especially in pigs ([[Cleft Palate|cleft plate]] and abortions)
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[[Category:Bones - Metabolic Pathology]]
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===Hypervitaminosis D===
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*May be of dietary or iatrogenic origin (has narrow safety margin)
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*Key features are hypercalcaemia with metastatic calcification of soft tissues
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*'''Acute poisoning'''
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**In dogs and cats often from rodenticides containing cholecalciferol
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**Grossly:
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***Gastrointestinal haemorrhage
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***Foci of [[Myocardial Mineralisation|myocardial discoloration]]
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**Microscopically:
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***Mucosal haemorrhage
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***Necrosis of crypts
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***Focal myocardial necrosis
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***Mineralisation of intestinal mucosa, [[Arterial Calcification#Medial calcification|blood vessel walls]], [[Pulmonary Calcification|lungs]] and kidneys
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*'''Chronic poisoning'''
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**Grossly:
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***Intense [[Bones - Anatomy & Physiology|osteoclastic activity]] -> active resorption of bone, especially [[Bones - Anatomy & Physiology|trabecular]]
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**Microscopically:
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***Excessive production of [[Bones - Anatomy & Physiology|osteoid]] - appears both eosinophilic and basophilic in different places
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***Marrow cavity may be obliterated
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***Mineralisation of soft tissues, especially [[Arterial Calcification|blood vessel walls]]
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**Due to inhibition of [[Calcium|Parathyroid Hormone (PTH)|PTH]] and increase of [[Calcium#Calcitonin|calcitonin]]
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[[Category:Bones - Metabolic Pathology]]
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===Fluorine poisoning===
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*F is widespread in nature
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*Pastures may be contaminated by industrial processes (e.g. brick manufacture)
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*'''Acute poisoning''':
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**Gastroenteritis
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**Nephrosis
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*'''Chronic poisoning''':
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**''Dental abnormalities''
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***Intoxication during teeth development
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***Foci of poor enamel formation - yellow, dark brown/black, chalky
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***Irregular wear of teeth, chip easily
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**''Osteodystrophy = Fluorosis''
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***Generalised skeletal disturbance
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***Most affected are metatarsals and mandibles
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***Periosteal hyperostosis + endosteal bone resorption -> thickened bones with enlarged marrow cavities
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[[Category:Bones - Metabolic Pathology]]
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===Lead poisoning===
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*Lead can bind to mineral portion of bone and cartilage
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*In young animals ingesting large dose at once
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** -> Lead induced malfunction of osteoclasts
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** -> Transverse band of increased density on radiographs of metaphysis = "lead line" = [[Retention of Elongated Primary Trabeculae|growth retardation lattice]]
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[[Category:Bones - Metabolic Pathology]]
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[[Category:Musculoskeletal System - Pathology]]
 
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