Lecture 11: Laryngeal Paralysis (Exam 2) Flashcards
Define laryngeal paralysis
Complete or partial failure of the arytenoid cartilages & vocal fold to abduct during inspiration
What nerves innervate the larynx
- Vagus
- Cranial laryngeal
- Recurrent laryngeal
- Caudal laryngeal
What can cause upper respiratory obstruction & mild to severe dyspnea
- Dysfunction of laryngeal muscle
- Dysfunction of recurrent laryngeal or vagus n
- Cricoarytenoid ankkylosis
What is laryngeal stridor
- Atrophy of the crocoarytenoideus dorsalis m causes cartilage to remain paramedian during inspiration
- Prevents maximal air intake & increasing airflow, the narrow rima glottidis increases resistance to airflow & creates turbulence giving rise to laryngeal stridor
What causes acquired laryngeal paralysis
Damage to the recurrent laryngeal nerve or intrinsic laryngeal muscles
What is GOLPP
- Geriatric onset laryngeal paralysis polyneuropathy
- Proposed as a more accurate term for dogs w/ acquired laryngeal paralysis where other causes have been ruled out
What signalment is seen w/ laryngeal paralysis
- Common in large breed dogs
- Males are affected two to four time more often than female
- Acquired idiopathic is common in middle aged or older dogs
- Dogs w/ unilateral laryngeal paralysis are rarely symptomatic
- Congenital laryngeal paralysis should be suspected in young large breed dogs w/ upper airway obstruction
Describe laryngeal paralysis in cats
- Uncommon
- Clinical sx is similar to a dogs
- Unilateral laryngeal paralysis can present w/ significant clinical sx
- Cause is unknown but associated w/ trauma, neoplastic invasion, & iatrogenic damage
What do px w/ laryngeal paralysis freq have
- Progressive inspiratory stridor
- Voice change
- Exercise intolerance
Px w/ laryngeal paralysis may have
- Increased stridor
- Dyspnea
- Cyanosis
- Coughing
- Gagging
- Vomiting
- Restlessness
- Anxiety
Which animals w/ laryngeal paralysis are @ risk for aspiration of food & saliva
All animals
What will be seen in a PE
- Nonspecific
- Labored breathing
- Cont. panting
- Hyperthermia
- Muscle wasting
- Weakness
- Neuro signs
What diagnostic imaging should be done
- Lateral cervical & thoracic radiographs
- Laryngeal paralysis cannot be dxed radiographically
- Ultrasound can be used to eval laryngeal fxn
What are the warnings to consider when correcting laryngeal paralysis
- Can result in devastating/life threatening aspiration
- Assess pre op esophageal fxn
- Even dogs w/ substantial esophageal dysfunction may have no evidence of esophageal dilation & no H/O regurgitation
Describe a laryngoscopy
- Req induction of light general ax
- Laryngeal motion must be compared w/ the phase of respiration for interpretation
- Intubation should be delayed to facilitate exam
- A norm larynx max abducts during inspiration
- In affected dogs the laryngeal cartilages are not located i a paramedian position & do not abduct during inspiration
- Paradoxical vocal fold movement can occur
- Fluttering of the vocal folds & arytenoid cartilages must not be mistaken for purposeful abduction
What medical management is done for mildly affected dogs
- often don’t req tx if they have sedentary lifestyle
- Avoid excessive weight gain & stress
What is the medical management for small dogs
More successfully managed w/ medical therapy than large dogs
What is some medical management for acute resp distress
- Improve ventilation
- Reducing laryngeal edema
- Min the animal’s stress
Which surgical tx is the treatment of choice
Unilateral arytenoid lateralization
Describe a permanent tracheostomy
Considered a salvage procedure for dogs most @ risk of aspiration pneumonia but is associated w/ a high rate of major & minor complications & req diligent post op & long term care
Describe the most common surgical tech
- Involves suturing the cricoid cartilage to the muscular process of the arytenoid cartilage
- Mimics the directional pull of the cricoarytenoid dorsalis m & rotates the arytenoid cartilage laterally
What is another name for unilateral arytenoid lateralization
Laryngeal tie back sx
How is a laryngeal tie back sx performed
- Larynx is exposed via lateral sx approach
- Separate the cricothyroid & cricoarytenoid articulations
- Place suture from the muscular process of the arytenoid to the dorsocaudal aspect of the cricoid or thyroid cartilage
- Tie the suture w/ enough tension to abduct the arytenoid cartilage mod
Describe post op care & assessment
- Give analgesics as needed
- Impaired glottic fxn may persist
- Exercise restriction for 6 to 8 W
- Barking min
- Occasional coughing can occur
- Bark is expected to be quiet & hoarse
What are some early complications of suture lateralization
- Hematoma formation
- Swallowing discomfort
- Temporary glottic impairment
- Incisional issue
- Coughing after eating & drinking
What are some complications
- cartilages may be insufficiently mineralized to retain sutures
- Older dogs may fracture or avulse the muscular process & cause failure of abduction & recurrence of clinical sx
- 10 to 20 % experience aspiration pneumonia
What factors are associated w/ a high risk of aspiration pneumonia
- Increasing age
- Temporary tracheostomy
- Progressive neuro dx
- Post op megaesophagus
- Esophageal dx
- Concurrent neoplastic dx
- opioids given post op
Describe the prognosis after unilateral lateralization
- Mild or no clinical sx @ rest do well w/out sx
- Mod to severe clinical sx may dev laryngeal collapse & acute resp obstruction
- Prognosis after lateralization is good
Describe a permanent tracheostomy
- Creation of a stoma in the ventral tracheal wall by suturing tracheal mucosa
- Rec for animals w/ upper respiratory obstruction causing mod to severe respiratory distress that cannot be successfully treated by other methods
what are the steps of a permanent tracheostomy
- Deviate trachea ventrally apposing the sternohyoid m horizontal mattress sutures dorsal to trachea, excise rectangular segment ventral tracheal wall
- I shaped incision is made in the mucosa after the cartilage segment is removed
- Excise loose skin adjacent to the stoma
- Use intradermal sutures to appose skin to the annular ligs & peritracheal tissues
- Complete closure w/ a simple continuous pattern
What should owners be warned about w/ a permanent tracheostomy
- Restrict swimming
- Vocalization is diminished or absent
- Increased risk for resp infections
- Ongoing care of the site is necessary
What are the key points of laryngeal paralysis
- Etiology of laryngeal paralysis
- Unilateral arytenoid lateralization is the treatment of choice
- Most common complication is aspiration pneumonia
- Permanent tracheostomy is best for cases that are high risk for aspiration pneumonia
