Laryngeal diseases Flashcards
Cartilages of larynx, which is which?
Name these structures.
Differences between the feline and canine larynx.
Cats do not have corniculate and cuneiform processes.
Wheezing upon inhalation is called
stridor
3 most common Laryngeal diseases in small animals
Laryngeal paralysis,
laryngeal collapse,
laryngeal masses
Clinical signs and findings in laryngeal diseases.
▪Respiratory distress, stridor, gagging, coughing, voice change, exercise intolerance
▪Labored, prolonged inspiration (stridor)
Animal can present in acute respiratory crisis with Potentially life-threatening inspiratory dyspnea. Check their temperature! This is also more common in summer months.
Laryngeal paralysis is more common in…
Describe this disease.
dogs than in cats.
Arytenoid cartilage fails to open during inspiration -> Narrowing of laryngeal opening -> Upper airway obstruction.
▪Unilateral or bilateral disease
▪Progressive clinical signs
Acquired disease
▪Damage to the recurrent laryngeal nerve or laryngeal muscles
▪ Or, due to Polyneuropathy (e.g. GOLPP), polymyopathy, trauma, thoracic masses.
▪Usually, a cause is not found -> idiopathic.
Congenital disease is possible but is very uncommon.
Typical signalment in laryngeal paralysis cases.
Old, large breed dogs such as
labrador, Golder Retriever, St. Bernard, Newfoundland, Irish Setter, Brittany Spaniel
Name these structures.
Congenital etiologies of laryngeal paralysis. (2)
▪Genetic trait
▪ Laryngeal paralysis—polyneuropathy
complex
Acquired etiologies of laryngeal paralysis. (4)
Accidental trauma
▪ Cervical penetrating wounds
▪ Strangulating trauma
Iatrogenic surgical trauma
▪ Cranial thoracic surgery
▪ Thyroidectomy/parathyroidectomy
▪ Tracheal surgery
▪ Ventral slot
Cervical/intrathoracic neoplasia
▪ Lymphoma
▪ Thymoma
▪ Thyroid carcinoma/ectopic thyroid carcinoma
Neuromuscular disease
▪ Main: Geriatric-onset laryngeal paralysis
polyneuropathy syndrome (GOLPP) (!)
Also these,
▪ Endocrinopathy (hypothyroidism,
hypoadrenocorticism)
▪ Immune-mediated
▪ Infectious
▪ Myasthenia gravis
▪ Polymyopathy
▪ Systemic lupus erythematosus
▪ Toxins (lead; organophosphates)
30% of dogs with laryngeal paralysis also have
hypothyroidism
The correlation mechanism is not known.
Diagnosis of laryngeal paralysis.
Image has megaesophagus in addition to laryngeal disease.
▪ Physical examination
▪ Neurological examination (check if any other nerves affected)
▪ Thoracic radiographs
▪ Thyroid panel, serum biochemistry,
complete blood count, urinalysis (part of a thorough work up)
Laryngoscopy in light(!) anesthesia
▪ Examination of laryngeal function
▪ Lack of arytenoid abduction during
inspiration – vocal cords don’t move
▪ Secondary inflammation and
swelling of laryngeal cartilages
▪ Be aware of paradoxical movement!
Laryngoscopy = ?
endoscopy of the larynx
Visualization of larynx, evaluation of laryngeal anatomy and function.
Fast and technically easy procedure
Light anesthesia! (e.g. plain butorphanol + Propofol to effect) Anesthetic agents may hamper laryngeal function so choose wisely.
Doxapram expectorant may be used to enhance respiration.
Indications for Laryngoscopy (6)
Voice change,
stridor, stertor,
increased inspiratory effort,
prolonged inspiration,
exercise intolerance,
coughing after eating or drinking
Describe the process of laryngoscopy.
Laryngoscope with a light source or endoscope
Patient in sternal recumbency
Depress the epiglottis gently with the tip of the laryngoscope or wooden tongue depressor to get a good view of the larynx.
Investigate the mouth, the pharynx and the tonsils.
Then evaluate the larynx for mucosal edema, secretions, everted saccules, laryngeal collapse, masses and other abnormalities.
Evaluate laryngeal movement and function. You need a nurse to verbally tell you when the patient is inspiring.
What does laryngeal paralysis look like on laryngoscopy?
Laryngeal paralysis has a Lack of arytenoid abduction during inspiration aka vocal cords don’t move.
Secondary inflammation and
swelling of laryngeal cartilages can be present (caused by the increased negative pressure from trying to breathe hard through the small rima glottis).
Be aware of paradoxical movement!
Treatment of acute dyspnea in laryngeal paralysis.
▪ Supplemental oxygen
▪ Sedation
Fast-acting corticosteroids
▪Dexamethasone 0.1-1 mg/kg IV
▪ Cooling if needed
▪ Intubation or tracheostomy if needed
Long-term medical management of laryngeal paralysis.
Does not cure the patient!
▪ Goal of No stress
▪Reduction of exercise
▪Weight loss
▪Corticosteroids?
Surgical treatment of laryngeal paralysis.
▪Unilateral arytenoid lateralization (left arytenoid is sutured to pharynx wall, approach from the outside of the neck)
▪Other techniques exist also
▪ Allows for Reduced airway resistance, less respiratory problems, improved quality of life.
Complications:
▪Aspiration pneumonia
Has a high complication rate, 10-20% get the above.
Describe Feline laryngeal paralysis
▪Uncommon in cats
▪Middle-aged to older cats
Unilateral and bilateral
▪Unilateral can lead to severe respiratory distress in cats (whereas pretty much only bilateral does this in dogs)
▪Etiology often unclear: Trauma, neoplasia, thyroid surgery
▪Perform laryngoscopy with caution because Cats prone to laryngospasm!
Laryngeal collapse is the Consequence of
chronic upper airway obstruction.
Occurs in Brachycephalic dogs, Norwich terriers (!, NOT in Norfolk terriers)
Laryngeal collapse stages (3) and description of them.
Stage I: eversion of laryngeal saccules
Stage II: the above + cuneiform processes of arytenoid collapse into laryngeal lumen
Stage III: the above + corniculate processes collapse toward midline
-> complete collapse of the larynx
Describe Laryngeal masses
Uncommon
Tumors of the larynx
▪ Several types reported
▪ Prognosis guarded
Inflammatory disease
▪Granulomatous, lympho-plasmocytic,
eosinophilic
Take a sample to differentiate!
Image: lymphoma in cat. Upper image laryngeal mass occluding larynx, lower image after lymphoma treatment.
eosinophilic granuloma can resemble laryngeal tumor
(left image is actually canine carcinoma)
differentiate the above with histology
