Laryngeal Hemiplegia

Laryngeal Hemiplegia



Basic Information image



Definition


Chronic and progressive degenerative neuropathy of the recurrent laryngeal nerve (RLN) resulting in loss of motor function of the intrinsic muscles of the larynx, which leads to paresis or paralysis of the associated arytenoid cartilage



Synonym(s)


Recurrent laryngeal neuropathy, laryngeal paralysis, “roaring”



Epidemiology



Genetics and Breed Predisposition


Large breeds are more commonly affected than small breeds and ponies. Familial correlation has been investigated with equivocal results. Height was also found to be associated with the incidence of RLN. RLN probably has a phenotypic as well as inherited component.



Risk Factors




• In most cases, RLN is idiopathic without defined risk factors.


• Trauma or diseases associated with the neck or larynx can affect either side but are considered more likely associated if the dysfunction is on the right side of the horse. Trauma includes perivascular jugular vein or carotid artery injection, surgery associated with the neck or larynx, and blunt or penetrating trauma to the neck.


• Diseases include guttural pouch mycosis and empyema, strangles abscessation, septic jugular thrombophlebitis, neoplasia of the neck, various central nervous system diseases, and toxicities.



Associated Conditions and Disorders


Vocal fold collapse



Clinical Presentation



Disease Forms/Subtypes




• Most commonly left laryngeal hemiplegia.


• Right laryngeal hemiplegia is uncommon and is usually associated with some type of trauma to the right RLN in the neck.



History, Chief Complaint




• Respiratory noise on inspiration, exercise intolerance


• Clinical signs will not be demonstrated in horses that are not exercising



Physical Exam Findings


On palpation of the throatlatch region, there is atrophy of the cricoarytenoideus dorsalis muscle on the affected side.



Etiology and Pathophysiology




• Idiopathic. The left nerve is thought to be affected more significantly because of its greater length relative to the right RLN.


• Chronic degenerative neuropathy of the RLN resulting in loss of the motor function of the intrinsic muscles of the larynx


• Distal axonopathy with demyelination and proliferation of Schwann cells, endoneurium, and perineurium in the RLN with most of the changes observed distally

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Laryngeal Hemiplegia

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