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Merck & Co (2008) '''The Merck Veterinary Manual'''
Merck & Co (2008) '''The Merck Veterinary Manual'''
==From Pathology Section==
[[Gastric Ulceration - all species]]
* Although ulcers are often secondary to other diseases, primary idiopathic peptic ulcers do occur, due to
** Hyperacidity
** Gastric carcinoma in older dog
* 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.
*# '''Mast cell tumours'''
*#*Boxers and Labradors are predisposed to these.
*#* Vomit continually together with abdominal pain.
*#* Ulcers are usually near the duodenum.
*#** Frequently secondarily infected.
*#** Often penetrate deeply.
*#* Actively secreting mast cell tumours produce histame, leasing to gastric hyperacidity and therefore secondary peptic ulcers.
*# '''Uraemia'''
*#* Gastric lesions usually occur with chronic renal disease.
*#** Gastrin is produced by the G cells of the gastric antrum during the gastric phase of digestion .
*#*** Acts on H2 receptors on parietal cells to increase production of HCl.
*#*** Increases release of histamine from gastric mucosal mast cells to increase HCl release.
*#** Serum levels of gastrin are increased in chronic renal disease in dogs and cats.
*#* In acute renal failure death ensues before gastric ulceration develops.
*#* '''Pathogenesis'''
*#** Loss of nephron and medullary concentration gradient in chronic interstitial nephritis mean collecting ducts cannot resorb fluid.
*#*** A common cause of interstitial nephritis in the dog was leptospirosis.
*#** Consequently, the animal drinks and urinates in enormous quantities, and urea is washed out with large quantities of fluid ("compensated renal failure").
*#** If fluid is restricted, urea cannot be washed out and the animal becomes uraemic.
*#*** Urea is excreted into [[Forestomach - Anatomy & Physiology|stomach]], giving it a horrible ammoniacal smell and filling it with brown smelly liquid.
*#*** Urea is also excreted into the [[Colon - Anatomy & Physiology|colon]].
*#** Urea in the stomach breaks down to ammonia, irritating the mucosa and contributing to gastric ulcer.
*#** Uraemia also causes arteriolar degeneration in the submucosa, leading to hypoxic damage to the mucosa. This is another contributing factor to gastric ulcer.
*#** [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|Vomiting]] causes dehydration and further raises blood urea.
*#*** A vicious circle is produced- ends in death by [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]], dehydration and shock.
*#** '''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.
* NSAIDs, Zollinger-Ellison syndrome (due to pancreatic gastrin-secreting tumour), cirrhosis and bile reflux can all also cause gastric ulcers in the dog.
[[Category:Gastric_Ulceration]][[Category:Dog]]