Laryngeal diseases Flashcards

1
Q

Cartilages of larynx, which is which?

A
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2
Q

Name these structures.

A
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3
Q

Differences between the feline and canine larynx.

A

Cats do not have corniculate and cuneiform processes.

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4
Q

Wheezing upon inhalation is called

A

stridor

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5
Q

3 most common Laryngeal diseases in small animals

A

Laryngeal paralysis,
laryngeal collapse,
laryngeal masses

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6
Q

Clinical signs and findings in laryngeal diseases.

A

▪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.

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7
Q

Laryngeal paralysis is more common in…

Describe this disease.

A

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.

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8
Q

Typical signalment in laryngeal paralysis cases.

A

Old, large breed dogs such as

labrador, Golder Retriever, St. Bernard, Newfoundland, Irish Setter, Brittany Spaniel

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8
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A
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8
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8
Q
A
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9
Q

Name these structures.

A
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10
Q

Congenital etiologies of laryngeal paralysis. (2)

A

▪Genetic trait
▪ Laryngeal paralysis—polyneuropathy
complex

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11
Q

Acquired etiologies of laryngeal paralysis. (4)

A

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)

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12
Q

30% of dogs with laryngeal paralysis also have

A

hypothyroidism

The correlation mechanism is not known.

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13
Q

Diagnosis of laryngeal paralysis.

Image has megaesophagus in addition to laryngeal disease.

A

▪ 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!

14
Q

Laryngoscopy = ?

A

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.

15
Q

Indications for Laryngoscopy (6)

A

Voice change,
stridor, stertor,
increased inspiratory effort,
prolonged inspiration,
exercise intolerance,
coughing after eating or drinking

16
Q

Describe the process of laryngoscopy.

A

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.

17
Q

What does laryngeal paralysis look like on laryngoscopy?

A

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!

18
Q

Treatment of acute dyspnea in laryngeal paralysis.

A

▪ Supplemental oxygen
▪ Sedation

Fast-acting corticosteroids
▪Dexamethasone 0.1-1 mg/kg IV

▪ Cooling if needed
▪ Intubation or tracheostomy if needed

19
Q

Long-term medical management of laryngeal paralysis.

A

Does not cure the patient!
▪ Goal of No stress
▪Reduction of exercise
▪Weight loss
▪Corticosteroids?

20
Q

Surgical treatment of laryngeal paralysis.

A

▪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.

21
Q

Describe Feline laryngeal paralysis

A

▪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!

22
Q

Laryngeal collapse is the Consequence of

A

chronic upper airway obstruction.

Occurs in Brachycephalic dogs, Norwich terriers (!, NOT in Norfolk terriers)

23
Q

Laryngeal collapse stages (3) and description of them.

A

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

24
Q

Describe Laryngeal masses

A

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.

25
Q
A

eosinophilic granuloma can resemble laryngeal tumor

(left image is actually canine carcinoma)

differentiate the above with histology