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| − | ==Anatomy and Physiology==
| + | #REDIRECT[[:Category:Pituitary Gland - Pathology]] |
| − | Anatomy and Physiology of the pituitary gland can be found [[Pituitary Gland - Anatomy & Physiology|here]].
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| − | ==General Pathological Principles==
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| − | Two major changes can occur in an endocrine gland:
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| − | *'''Failure of hormone production''':
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| − | **Destruction or lack of cells.
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| − | **Lack of trophic drive.
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| − | *'''Overproduction of hormone''':
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| − | **Hyperplasia or neoplasia.
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| − | **Excessive trophic drive.
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| − | ==Pituitary Hypofunction==
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| − | ===[[Congenital Panhypopituitarism]]===
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| − | ===Pituitary cysts===
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| − | [[Image:Pituitary cyst.jpg|right|thumb|125px|<small><center>'''Pituitry cyst'''. Courtesy of A. Jefferies</center></small>]]
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| − | Act as space-occupying lesions producing a pathology of the pituitary. May arise from two developmental structures:
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| − | *The '''cranio-pharyngeal ducts''' which are the route by which the developing anterior pituitary ascends from the pharynx. The craniopharyngeal ducts are the neck of Rathke's pouch which, during development, narrows, closes and separates the vesicle of Rathke's pouch from the oral cavity. These cysts have columnar ciliated epithelial cells lining the cyst and contain mucin. <br>The craniopharyngeal ducts may also become neoplastic; '''Craniopharyngioma'''. These tumours contain single or multiple cysts.
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| − | *'''Rathke's Pouch''' which may fail to differentiate and becomes cystic.
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| − | [[Category:Pituitary Gland - Pathology]]
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| − | ===Pituitary Neoplasia===
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| − | Tumours within the pituitary fossa may be functional and sectrete trophic factors. However, more commonly they are non-functional and are space-occupying lesions.
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| − | Pressure on neighbouring structures causes clinical signs, for example:
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| − | *Pressure on the optic chiasma produces ocular signs.
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| − | *Pressure on the hypothalamus may lead to [[Frohlich's Adiposogenital Syndrome - Pathology|Frohlich's adiposogenital syndrome]].
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| − | *Pressure on the neurohyposphysis may lead to failure of ADH secretion. This will allow large volumes of water to be lost form the kidney; [[Diabetes Insipidus]].
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| − | [[Image:Pituitary tumour.jpg|right|thumb|125px|<small><center>'''Pituitary neoplasia'''. Courtesy of A. Jefferies</center></small>]]
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| − | Neoplasia may be derived from:
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| − | *Pituitary itself.
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| − | *Surrounding brain tissue.
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| − | *Ependyma.
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| − | ====Pituitary neoplasia in the horse====
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| − | Neoplasia usually occurs in the ''pars intermedia'' of the anterior pituitary and compresses the hypothalamus.
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| − | ''Clinical signs'':
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| − | *Polyuria and polydipsia.
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| − | *Increased appetite reulting in increased food intake and downregulation of insulin receptors. This leads to a hyperglycaemia.
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| − | *Somnolence.
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| − | *Muscle wekaness.
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| − | *Hirsutism.
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| − | *Hyperhidrosis.
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| − | [[Category:Pituitary Gland - Pathology]]
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| − | [[Category:Neoplasia]]
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| − | ==Pituitary Hyperfunction==
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| − | [[Gigantism]]
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| − | ===[[Acromegaly]]===
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