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| − | ===Functional Obstruction=== | + | ===[[:Category:Intestine - Functional Obstruction]]=== |
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| − | ====Paralytic Ileus====
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| − | * A common condition.
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| − | * Occurs following trauma or abdominal surgery.
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| − | * Stasis of gut flow due to failure of [http://en.wikipedia.org/wiki/Peristalsis| peristalsis].
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| − | ** Leads to distension with gas and fluid, as well as a flaccid intestinal wall.
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| − |
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| − | =====Causes=====
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| − |
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| − | * Anything which stops peristalsis, e.g.
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| − | ** Damage to nerve supply to intestine (autonomic nervous system)
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| − | ** Pain
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| − | ** Abnormal metabolism
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| − | ** Toxaemia
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| − | ** Electrolyte imbalance such as hypocalcaemia, hypomagnesaemia, and hypokalaemia.
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| − | * Also in
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| − | ** Diabetes mellitus
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| − | ** Uraemia
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| − | ** Tetanus
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| − | ** Lead poisoning.
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| − |
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| − | =====Pathology=====
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| − |
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| − | * loss of smooth muscle tone leads to a flaccid bowel.
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| − | * Bowel is distended with fluid.
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| − |
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| − | =====Pathogenesis=====
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| − |
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| − | * Intestine susceptible to neurogenic damage during an operation.
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| − | * Peristalsis fades away over a few days producing paralytic (adynamic) ileus.
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| − | * Particularly occurs if bowel handled roughly, or if serosa gets cold and dry at surgery.
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| − | * Very difficult to start peristalsis again but will sometimes respond to pharmacological or electrical stimulation.
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| − | * The horse is very susceptible, and the dog is somewhat suscpeitble.
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| − | ====Dysautonomia====
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| − |
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| − | * Most notably affects horses and cats.
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| − | =====Equine dysautonomia, or grass sickness=====
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| − | * Most prevalent in the UK and western Europe.
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| − | ** Common in wetter areas, e.g. the South West.
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| − | * Seen in horses out at pasture in late summer and autumn.
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| − | * Usually affects young adults.
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| − | ** 6-7 years old.
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| − | * '''Clinical'''
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| − | ** Acute oneset:
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| − | *** Muscular tremors
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| − | *** Abdominal pain
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| − | *** Does not eat
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| − | *** Constipation
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| − | *** Become severly tympanic in acute cases
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| − | *** Dull and restless
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| − | *** Avoid swallowing
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| − | *** Salivate excessively
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| − | ** Degenerative lesions are seen in the autonomic nerve ganglia, including enteric plexuses
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| − | ** May either:
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| − | *** Progress rapidly to death
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| − | *** Take a slower clinical course.
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| − | **** Eat a bit, but food drops out of mouth
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| − | **** Go on to die slowly.
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| − | ** Some horses recover
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| − | *** This is very unlikely, and the condition is usually fatal.
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| − | ** Clinically difficult to diagnose - signs are confined to the gut.
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| − | *** Easy to diagnose on post mortem
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| − | * '''Pathology'''
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| − | ** [[Forestomach - Anatomy & Physiology|Stomach]] and [[Small Intestine - Anatomy & Physiology|small intestine]] large amounts of contain watery yellow fluid.
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| − | *** There is an abrupt change in the [[Large Intestine - Anatomy & Physiology|large intestine]], where no fluid is present.
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| − | **** [[Large Intestine - Anatomy & Physiology|large intestine]] has very dry mucoid contents.
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| − | * '''Pathogenesis'''
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| − | ** Due to functional obstruction at ileocaecal valve and a degree of paralytic ileus of the [[Small Intestine - Anatomy & Physiology|small intestine]].
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| − | ** The exact cause is unknown, but a type of bacterial or fungal toxin which may damage autonomic nervous system ganglia may be involved.
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| − | *** ''[[Clostridium botulinum]]'' is thought to be involved.
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| − | * A similar condition seen in hares
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| − | ** Certain yeares almost seem to have outbreaks.
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| − | * Certain pastures at certain times of year produce grass sickness quite often.
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| − | ** A definitive diagnosis must be made - if the condition is due to the grazing we need to know.
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| − | *** E.g. if on livery or stud grazing, may put people off going there.
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| − | * 'Diagnosis'''
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| − | ** At post mortem look for degenerative changes in coeliaco-mesenteric ganglia - need to examine histologically.
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| − | *** Ganglia are peanut sized and found in perirenal fat between adrenal gland and the aorta.
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| − |
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| − | =====Feline dysautonomia, or Key-Gaskell Syndrome=====
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| − | [[Image:Ba 250 07.jpg|thumb|right|Histological section of degenerate neuron in feline dysautonomia(Courtesy of Susan Rhind)]]
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| − | * Occurs mostly in the UK and continental Europe.
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| − | * Is also of unknown aetiology. Suggested causative factors include:
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| − | ** Environmental toxins
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| − | ** Infectious agents
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| − | ** Botulinum toxins .
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| − | * Clinical signs:
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| − | ** Anorexia
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| − | ** Depression
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| − | ** Bradycardia
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| − | ** Decreased lacrimation,
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| − | ** Altered pupillary dilataion,
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| − | ** [[Megaoesophagus]]
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| − | ** Constipation.
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| − | * Degenerative lesions of autonomic nerve ganglia can be seen.
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| − | * Also occurs in the [[Key-Gaskell Syndrome|oesophagus]].
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| | [[Category:Intestine - Physical Disturbances]] | | [[Category:Intestine - Physical Disturbances]] |