Difference between revisions of "Ragwort Toxicity"
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==Prognosis== | ==Prognosis== | ||
| − | + | Horses with chronic liver failure due to ragwort poisoning have a poor prognosis for survival as the damage to the liver is severe by the time clinical signs are obvious. | |
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==References== | ==References== | ||
* Knottenbelt, D.C. '''A Handbook of Equine Medicine for Final Year Students''' ''University of Liverpool'' | * Knottenbelt, D.C. '''A Handbook of Equine Medicine for Final Year Students''' ''University of Liverpool'' | ||
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==Hepatotoxicity== | ==Hepatotoxicity== | ||
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*'''pyrrolizidine alkaloids''' | *'''pyrrolizidine alkaloids''' | ||
**toxic principle converted in the body to the toxic intermediate '''pyrroles''' and their esters | **toxic principle converted in the body to the toxic intermediate '''pyrroles''' and their esters | ||
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*it is likely that the vascular component of the attempted repair of the chronic damage by fibrosis (really a type of granulation tissue) aids the shunting from the portal triads to the central vein and thereby bypassing the hepatocytes | *it is likely that the vascular component of the attempted repair of the chronic damage by fibrosis (really a type of granulation tissue) aids the shunting from the portal triads to the central vein and thereby bypassing the hepatocytes | ||
*other plant and fungal toxins perform in the same way | *other plant and fungal toxins perform in the same way | ||
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[[Category:Hepatotoxicity, Chronic]][[Category:Horse]][[Category:Sheep]] | [[Category:Hepatotoxicity, Chronic]][[Category:Horse]][[Category:Sheep]] | ||
[[Category:To_Do_- lizzyk]] | [[Category:To_Do_- lizzyk]] | ||
Revision as of 16:31, 25 July 2010
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This article is still under construction. |
Description
Ragwort (Senecio jacobea) is part of the daisy family, a flowering plant with completely yellow flowerheads. It commonly grows on wasteland and grazing pastures. It is poisonous to livestock with Horses and cattle being more susceptible than sheep. When ingested over long periods of time it causes hepatotoxicity which in the severe form is invariably fatal. Exposure to the toxin is usually via ingestion of contaminated hay or silage as the animal will avoid it in the fresh form.
The toxin is a pyrrolizidine alkaloid.
Signalment
Diagnosis
Clinical signs
- Weight loss
- Hepatic insufficiency
- Hepatic encephalopathy
Biopsy
Treatment
Prognosis
Horses with chronic liver failure due to ragwort poisoning have a poor prognosis for survival as the damage to the liver is severe by the time clinical signs are obvious.
References
- Knottenbelt, D.C. A Handbook of Equine Medicine for Final Year Students University of Liverpool
- Rose, R. J. and Hodgson, D. R. (2000) Manual of Equine Practice (Second Edition) Sauders.
Hepatotoxicity
- pyrrolizidine alkaloids
- toxic principle converted in the body to the toxic intermediate pyrroles and their esters
- cause intitial and continued damage to hepatocytes
- have an anti-mitotic effect whilst allowing continued synthesis within the cell and its nucleus
- causes a marked increase in the size of parenchymal cells, a phenomenon termed 'megalocytosis'
- these very enlarged hepatocytes can be up to 20 times bigger
- the enlarged cells are closely apposed so that the sinusoids may not be evident
- it is likely that the vascular component of the attempted repair of the chronic damage by fibrosis (really a type of granulation tissue) aids the shunting from the portal triads to the central vein and thereby bypassing the hepatocytes
- other plant and fungal toxins perform in the same way
| Also known as: | Senecio jacobea |