Difference between revisions of "Consequences of Gastric Disease - Pathology"

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==Vomiting==
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==[[Vomiting]]==
 
 
* Has potentially lethal effects in the monogastric animal.
 
 
 
 
 
===Water Loss===
 
 
 
* Fluid loss is evident as:
 
*# An increased PCV or haematocrit.
 
*# An increased total protein concentration.
 
*# A prerenal azotaemia.
 
 
 
 
 
===Gastric Electrolyte Loss===
 
 
 
* The main losses are of H<sup>+</sup> and Cl<sup>-</sup>, and also K<sup>+</sup>
 
* Can potentially cause metabolic alkalosis, although this is only likely with disease which stops at the pylorus, e.g.: pyloric outflow obstruction.
 
** In cases where mild alkalosis occurs, homeostatic mechanisms produce a more alkaline urine to restore normal body pH.
 
** However, in severe metablolic alkalosis with marked dehydration, acidic urine may be produced- this is termed '''paradoxical aciduria'''.
 
*** Because [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]] induceses hypokalaemia, there is an overriding stimulus in the kidney for Na<sup>+</sup> (and therefore water) retention.
 
*** Na+ can only be resorbed in exchange for H+
 
**** H<sup>+</sup> is therefore excreted in the urine, causing it to be acidic.
 
*** [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|Vomiting]] also induces hypochloraemia, meaning bicarbonate rather than chloride is resorbed with the Na+ to maintain electrical neutrality
 
**** This perpetuates the alkalosis.
 
* [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|Vomiting]] does not occur in the ruminant although [[The Abomasum - Anatomy & Physiology|abomasal]] content may reflux into the [[Stomach and Abomasum - Anatomy & Physiology|forestomachs]].
 
** Sequestration of secretions in the [[The Abomasum - Anatomy & Physiology|abomasum]] will have similar effects to pyloric outflow obstruction with [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]] in the monogastric animal.
 
*** e.g. abomasal torsion
 
*** Causes dehydration, hypochloraemia, hypokalaemia and metabolic alkalosis.
 
 
 
 
 
* Lesions in the [[Small Intestine - Anatomy & Physiology|small intestine]] can also lead to [[Control of Feeding - Anatomy & Physiology#The Vomit Reflex|vomiting]]
 
** Both gastric acid and pancreatic and intestinal bicarbonate secretions are lost
 
*** Animal consequently has a normal pH or may even be acidotic.
 
  
 
==Raised Intraluminal pH==
 
==Raised Intraluminal pH==
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* Causes failure of digestion.  
 
* Causes failure of digestion.  
 
** Anorexia and weight loss follow.  
 
** Anorexia and weight loss follow.  
* Increases the number of bacteria in the [[Forestomach - Anatomy & Physiology|stomach]].
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* Increases the number of bacteria in the [[Monogastric Stomach - Anatomy & Physiology|stomach]].
 
* Diarrhoea reults
 
* Diarrhoea reults
 
** Cause is unknwn is unknown but appears to be related to the elevated pH.
 
** Cause is unknwn is unknown but appears to be related to the elevated pH.

Latest revision as of 13:15, 6 September 2010


Vomiting

Raised Intraluminal pH

  • Associated with some forms of gastritis.
    • e.g. Ostertagiasis
  • Causes failure of digestion.
    • Anorexia and weight loss follow.
  • Increases the number of bacteria in the stomach.
  • Diarrhoea reults
    • Cause is unknwn is unknown but appears to be related to the elevated pH.

Hyperacidity

  • May develop in certain gastric disturbances
  • Thought to be a contributory factor in peptic ulceration.

Anaemia

  • May also develop in certain gastric diseases
  • Is usually haemorrhagic in nature
    • Due to bleeding from gastric ulceration.