Changes

==== [[Myasthenia Gravis]]  ====

==== [[Myasthenia Gravis]]  ====

Myasthenia gravis is a disease of the neuromuscular junction that occurs due to a defect or absence of nicotinic acetylcholine receptors on the post-synaptic membrane (in the congenital form) or due to the presence of antibodies that bind to the receptors and prevent them from functioning normally (in the acquired form). The classical focal form of myasthenia gravis affects only the extraocular muscles, the cranial oesophagus and the muscles innervated by cranial nerves V, VII and IX. 80% of animals diagnosed with myasthenia gravis have megaoesophagus at presentation.  

Myasthenia gravis is a disease of the neuromuscular junction that occurs due to a defect or absence of nicotinic acetylcholine receptors on the post-synaptic membrane (in the congenital form) or due to the presence of antibodies that bind to the receptors and prevent them from functioning normally (in the acquired form). The congential form is primarily seen in breeds such as the Minitaure Daschund and Jack Russell Terrier and signs are usually seen from 6-8weeks of age. The acquired form occures fomr 6+ months and is seen in breeds such as Labrador, Golden Retreiver and German Shepherd Dogs. The classical, focal form, of myasthenia gravis affects only the extraocular muscles, the cranial oesophagus and the muscles innervated by cranial nerves V, VII and IX and occurs in aorund 30% of cases. The generalised, exercise intolerance plus megaoesophagus form, is seen in 60% of cases. 80% of animals diagnosed with myasthenia gravis have megaoesophagus at presentation.

=== Acquired Megaoesophagus  ===

=== Acquired Megaoesophagus  ===

== Diagnosis  ==

== Diagnosis  ==

=== Diagnostic Imaging  ===

=== Diagnostic Imaging  ===

*Small boluses of food OR a liquid gruel should be fed to the animal little and often, depending on preference of the dog and owner, as this reduces the risk of aspiration.  

*Small boluses of food OR a liquid gruel should be fed to the animal little and often, depending on preference of the dog and owner, as this reduces the risk of aspiration.  

*The '''forelimbs of the animal should be raised''' for 10-15 minutes after each to meal to allow the food to reach the stomach.  

*The '''forelimbs of the animal should be raised''' for 10-15 minutes after each to meal to allow the food to reach the stomach.  

*The animal should be monitored constantly by its owner for the development of signs of '''aspiration pneumonia''', a frequent recurrent problem in animals with congenital megaoesophagus. This condition should be treated aggressively with intra-venous bactericidal antibiotics (preferably selected on the basis of results from a culture of a broncho-alveolar lavage), coupage and nebulisation.<br>

*The animal should be monitored constantly by its owner for the development of signs of '''aspiration pneumonia''', a frequent recurrent problem in animals with congenital megaoesophagus. This condition should be treated aggressively with intra-venous bactericidal antibiotics (preferably selected on the basis of results from a culture of a broncho-alveolar lavage), coupage and nebulisation.

*Gastrostomy tubes have been shown to decreased the amount of regurgitation, however, some animals may still regurgitate saliva.<br>

== Prognosis  ==

== Prognosis  ==

Good to poor; depending on underlying cause.  

Good to poor; depending on underlying cause.  

Sudden death due to aspiration pneumonia is a risk that may occur at any time.  

Sudden death due to '''aspiration pneumonia''' is a risk that may occur at any time.  

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== References  ==

== References  ==

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company <br>[[Category:Oesophagus_-_Pathology]] [[Category:Oesophageal_Diseases_-_Cat]] [[Category:Oesophageal_Diseases_-_Dog]] [[Category:To_Do_-_Kate]] [[Category:Oesophageal_Diseases_-_Cattle]] [[Category:Oesophageal_Diseases_-_Horse]]

Blood, D.C. and Studdert, V. P. (1999) Saunders Comprehensive Veterinary Dictionary (2nd Edition) Elsevier Science <br>Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company <br>Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company

 

 

[[Category:Oesophagus_-_Pathology]] [[Category:Oesophageal_Diseases_-_Cat]] [[Category:Oesophageal_Diseases_-_Dog]] To_Do_Review [[Category:Oesophageal_Diseases_-_Cattle]] [[Category:Oesophageal_Diseases_-_Horse]]