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| ====Dog==== | | ====Dog==== |
− | [[Gastric Ulceration - all species]]
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− | * Although ulcers are often secondary to other diseases, primary idiopathic peptic ulcers do occur, due to
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− | ** Hyperacidity
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− | ** Gastric carcinoma in older dog
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− | * Secondary ulcers are often associated with systemic diseases particularly '''uraemia''' and '''mast cell tumours'''. Gastric ulcer may be the cause of death but is not the primary disease.
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− | *# '''Mast cell tumours'''
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− | *#*Boxers and Labradors are predisposed to these.
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− | *#* Vomit continually together with abdominal pain.
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− | *#* Ulcers are usually near the duodenum.
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− | *#** Frequently secondarily infected.
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− | *#** Often penetrate deeply.
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− | *#* Actively secreting mast cell tumours produce histame, leasing to gastric hyperacidity and therefore secondary peptic ulcers.
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− | *# '''Uraemia'''
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− | *#* Gastric lesions usually occur with chronic renal disease.
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− | *#** Gastrin is produced by the G cells of the gastric antrum during the gastric phase of digestion .
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− | *#*** Acts on H2 receptors on parietal cells to increase production of HCl.
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− | *#*** Increases release of histamine from gastric mucosal mast cells to increase HCl release.
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− | *#** Serum levels of gastrin are increased in chronic renal disease in dogs and cats.
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− | *#* In acute renal failure death ensues before gastric ulceration develops.
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− | *#* '''Pathogenesis'''
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− | *#** Loss of nephron and medullary concentration gradient in chronic interstitial nephritis mean collecting ducts cannot resorb fluid.
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− | *#*** A common cause of interstitial nephritis in the dog was leptospirosis.
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− | *#** Consequently, the animal drinks and urinates in enormous quantities, and urea is washed out with large quantities of fluid ("compensated renal failure").
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− | *#** If fluid is restricted, urea cannot be washed out and the animal becomes uraemic.
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− | *#*** Urea is excreted into [[Forestomach - Anatomy & Physiology|stomach]], giving it a horrible ammoniacal smell and filling it with brown smelly liquid.
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− | *#*** Urea is also excreted into the [[Colon - Anatomy & Physiology|colon]].
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− | *#** Urea in the stomach breaks down to ammonia, irritating the mucosa and contributing to gastric ulcer.
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− | *#** Uraemia also causes arteriolar degeneration in the submucosa, leading to hypoxic damage to the mucosa. This is another contributing factor to gastric ulcer.
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− | *#** [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|Vomiting]] causes dehydration and further raises blood urea.
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− | *#*** A vicious circle is produced- ends in death by [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]], dehydration and shock.
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− | *#** '''Note:''' If an animal in compensated renal failure is given anaesthetic, it will not drink much. It then may start to [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomit]] and die due to uraemia.
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− | * NSAIDs, Zollinger-Ellison syndrome (due to pancreatic gastrin-secreting tumour), cirrhosis and bile reflux can all also cause gastric ulcers in the dog.
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| ====Pig==== | | ====Pig==== |