Difference between revisions of "Pituitary Neoplasia"
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| − | ==== | + | ====Pituitary neoplasia in the horse==== |
Neoplasia usually occurs in the ''pars intermedia'' of the anterior pituitary and compresses the hypothalamus. | Neoplasia usually occurs in the ''pars intermedia'' of the anterior pituitary and compresses the hypothalamus. | ||
Revision as of 14:31, 21 February 2011
Tumours within the pituitary fossa may be functional and sectrete trophic factors. However, more commonly they are non-functional and are space-occupying lesions. Pressure on neighbouring structures causes clinical signs, for example:
- Pressure on the optic chiasma produces ocular signs.
- Pressure on the hypothalamus may lead to Frohlich's adiposogenital syndrome.
- 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.
Neoplasia may be derived from:
- Pituitary itself.
- Surrounding brain tissue.
- Ependyma.
Pituitary neoplasia in the horse
Neoplasia usually occurs in the pars intermedia of the anterior pituitary and compresses the hypothalamus.
Clinical signs:
- Polyuria and polydipsia.
- Increased appetite reulting in increased food intake and downregulation of insulin receptors. This leads to a hyperglycaemia.
- Somnolence.
- Muscle wekaness.
- Hirsutism.
- Hyperhidrosis.