Difference between revisions of "Laryngeal Hemiplegia"

From WikiVet English
Jump to navigation Jump to search
(Created page with "*In Horses: *Unilateral paralysis of arytenoids *Common 2-13% training thoroughbreds *Damaged/ dysfunctional recurrent laryngel nerve (branch of vagus) *Mostly left side affected...")
(One intermediate revision by the same user not shown)
Line 14: Line 14:
 
**Trauma
 
**Trauma
  
* These horses are also known as "'''roarers'''"
 
* Equine laryngeal hemiplegia is a very common condition.
 
 
===Pathogenesis===
 
 
# The disease starts with an idiopathic degeneration of the left recurrent laryngeal nerve.
 
# This leads to atrophy of the left dorsal cricoarytenoid muscle.
 
# Without the use of this muscle, the horse is unable to abduct the left arytenoid cartilage and vocal fold.
 
# Airways are therefore partially obstructed on inspiration.
 
 
[http://w3.vet.cornell.edu/nst/nst.asp?Fun=F_KSsrch&kw=HEMIPLEGIA View images courtesy of Cornell Veterinary Medicine]
 
 
Idiopathic Laryngeal Hemiplegia:
 
:Progressive loss of fibres (esp. large diameter) within left recurrent laryngeal nerve compared to right
 
:Dying back axonopathy with myelin sheath involvement:
 
:Degenerating fibres
 
:Regenerating clusters
 
:De/Re-myelination
 
:Flattening of nerve between aorta & trachea
 
:Inspiratory 'roaring' noise - flapping of vocal fold
 
:'Slap test' - adduction of contralateral arytenoid during expiration
 
:Endoscopic examination - assymetric arytenoids, poor abduction of left vocal fold.
 
:Palpable atrophy of laryngeal musculature
 
:Laryngeal Ventriculectomy (Hobday procedure)
 
:'Tie Back'
 
:Laryngeal muscle prosthesis
 
:Prognosis usually good
 
  
 
==Test yourself with the Larynx Pathology Flashcards==
 
==Test yourself with the Larynx Pathology Flashcards==
Line 48: Line 21:
 
[[Category:Larynx - Pathology]]
 
[[Category:Larynx - Pathology]]
 
[[Category:Respiratory System - Degenerative Pathology]]
 
[[Category:Respiratory System - Degenerative Pathology]]
[[Category:Respiratory Diseases - Horse]]
 
[[Category:Central Nervous System - Degenerative Pathology]]
 
[[Category:Peripheral Nervous System - Pathology]]
 

Revision as of 13:51, 19 February 2011

  • In Horses:
  • Unilateral paralysis of arytenoids
  • Common 2-13% training thoroughbreds
  • Damaged/ dysfunctional recurrent laryngel nerve (branch of vagus)
  • Mostly left side affected, occasionally also the right nerve
  • Demyelination of nerve fibres, and leading to atrophy of intrinsic laryngeal muscles particularly the adductor (cricoarytenoid) which allows the left arytenoid cartilage to lean into the laryngeal lumen
  • The 'roaring' is noticeable after exercising
  • The aetiology is not properly established but suggested factors are:
    • Length of the left recurrent nerve
    • Extension neuritis in guttural pouch mycosis
    • Neurotoxins - organophosphorus compounds may produce similar degenerative changes in the nerves
    • Enlarged retropharyngeal lymph nodes
    • Neoplasia
    • Trauma


Test yourself with the Larynx Pathology Flashcards

Larynx Pathology Flashcards