Lecture 11 (Laryngeal Paralysis)

complete or partial failure of the arytenoid cartilages and vocal folds to abduct during inspiration

define laryngeal paralysis

Vagus nerve

the intrinsic muscles of the dog's larynx are innervated by somatic efferent axons from the _______ nerve

Cranial laryngeal nerve

some axons leave the vagus in the [cranial/caudal] laryngeal nerve to innervate the cricothyroid muscle; others provide sensory innervation to the mucosa

Recurrent laryngeal nerve

the ________ laryngeal nerve, a branch of the vagus, terminates as the caudal laryngeal nerve, which innervates the remaining intrinsic muscles of the larynx

Caudal laryngeal nerve

the [cranial/caudal] laryngeal nerve travels along the dorsolateral surface of the trachea and continues over the lateral surface of the cricoarytenoideus dorsalis before deviating to the medial surface of the thyroid cartilage lamina

-White-coated German Shepherd Dogs
-Bouviers des Flandres
-Bull Terriers
-Siberian Huskies

congenital, inherited laryngeal paralysis occurs in which dog breeds?

-Dalmatians
-Rottweilers
-Leonberger Dogs
-Pyrenean Mountain Dogs (Great
Pyrenees)

a congenital laryngeal paralysis- polyneuropathy complex associated with dying back of peripheral nerves has been recognized in which dog breeds?

-polyneuropathy

-polymyopathy

-accidental or iatrogenic trauma

-intrathoracic or extrathoracic masses

-many other causes have been proposed

acquired laryngeal paralysis is caused by damage to the recurrent laryngeal nerve or intrinsic laryngeal muscles is most often attributed to...

GOLPP (geriatric onset laryngeal paralysis polyneuropathy)

the abbreviation ______ has been proposed as a more accurate term for dogs with acquired laryngeal paralysis where other causes have been ruled out

-more common in large-breed dogs

-males are affected two to four times more often than females

-acquired idiopathic laryngeal paralysis is most common in middle-aged or older dogs

-congenital laryngeal paralysis should be suspected in young (<1 year of age) large-breed dogs with upper airway obstruction

what signalment would you expect to see in a dog with laryngeal paralysis?

true

t/f: dogs with unilateral Laryngeal Paralysis are rarely symptomatic

-uncommon in cats

-clinical presentation is similar to that of the dog

-cats with unilateral laryngeal paralysis can present with significant clinical signs

-prevalence of left-sided unilateral laryngeal paralysis has been noted in cats

discuss laryngeal paralysis in cats

-progressive inspiratory stridor
-voice change
-exercise intolerance

what history is frequently associated with laryngeal paralysis?

tracheal collapse

laryngeal paralysis occurs in approximately one-third of dogs with....

aspiration of food and saliva!

all animals with laryngeal paralysis are at risk for...

-exam findings are nonspecific
-labored breathing
-continuous panting
-hyperthermia
-muscle wasting
-weakness
-other neurologic signs

what physical exam findings are associated with laryngeal paralysis?

-laryngeal paralysis cannot be diagnosed radiographically

-ultrasound can be used to evaluate laryngeal function

discuss diagnostic imaging of laryngeal paralysis

aspiration

*critical to assess preoperative esophageal function preoperatively

corrective surgery in dogs with proximal esophageal dysfunction may result in devastating/life-threatening _________

in affected dogs, the laryngeal cartilages are located in a paramedian position and do not abduct during inspiration

in dogs affected with laryngeal paralysis, where are the laryngeal cartilages located?

hematologic and serum biochemistry findings are usually normal

what laboratory findings are associated with laryngeal paralysis?

false - small dogs are more successfully managed with medical therapy

t/f: large dogs with laryngeal paralysis are more successfully managed with medical therapy than small dogs

-mildly affected dogs often require no treatment if they maintain a sedentary lifestyle and avoid excessive weight gain and stress

-exercise restriction and elimination of precipitating causes may be beneficial when clinical signs are mild

how do you medically manage mildly affect dogs with laryngeal paralysis?

-lateral recumbency with the neck over a rolled towel and rotated to elevate the ipsilateral mandible

-head may be stabilized by taping it to the table

how is a patient positioned for an arytenoid cartilage lateralization?

Unilateral Arytenoid Lateralization

which surgery is the treatment of choice for laryngeal paralysis?

-permanent tracheostomy

-it is associated with a high rate of major and minor complications and requires diligent postoperative and long-term care

which surgery is considered a salvage procedure for dogs most at risk of aspiration pneumonia that have laryngeal paralysis?

-the most common technique involves suturing the cricoid cartilage to the muscular process of the arytenoid cartilage

-this mimics the directional pull of the cricoarytenoid dorsalis muscle and rotates the arytenoid cartilage laterally

what is the most common technique when performing a Laryngeal Tie-Back surgery?

-hematoma formation

-swallowing discomfort

-temporary glottic impairment

-incisional issues

-coughing after eating and drinking

*these complications usually resolve within a few days unless aspiration occurs

what complications can arise from a Laryngeal Tie-Back surgery?

10% to 20%

aspiration pneumonia occurs in approximately ___% to ___% of dogs that underwent a Laryngeal Tie-Back surgery

-mild or no clinical signs at rest do well without surgery

-moderate to severe clinical signs may develop laryngeal collapse and acute respiratory obstruction

-prognosis after unilateral lateralization is good → > 90% of patients have less respiratory distress and improved exercise tolerance

describe the post-operative prognosis for dogs having surgery for Laryngeal Paralysis

upper respiratory obstruction causing moderate to severe respiratory distress (e.g., laryngeal paralysis, laryngeal collapse, upper airway neoplasia) that cannot be successfully treated by other methods

a permanent tracheostomy is recommended for animals with...

-must be restricted from swimming

-vocalization is diminished or absent

-increased risk for respiratory infections

-ongoing care of the site will be necessary to keep it clean

if you do a permanent tracheostomy, what should owners be warned about?