239 diseases of larynx Flashcards
what is the function of the larynx?
- regulates airflow
- protects lower airway from aspiration during swallowing
- controls phonation
what breeds commonly get acquired laryngeal paralysis?
Golden Retrievers St Bernards Newfoundlands Irish Setters Brittany Spaniels
What is acquired laryngeal paralysis most often caused by?
= most often damage to recurrent laryngeal nerve or intrinsic laryngeal muscles often due to polyneuropathy, polymyopathy, accidental, or iatrogenic trauma or intra/extrathoracic masses
What other proposed aetiologies of laryngeal paralysis?
Congenital:
- genetic trait
- laryngeal paralysis-polyneuropathy complex
Accidental trauma:
- cervical penetrating wounds
- strangulating trauma
Iatrogenic surgical trauma:
- cranial thoracic surgery
- thyroidectomy/parathyroidectomy
- tracheal surgery
- ventral solt
Cervical/intrathoracic neoplasia
- lymphoma
- thymoma
- thyroid carcinoma/ectopic thyroid carcinoma
Neuromuscular disease - geriatric-onset laryngeal paralysis polyneuropathy syndrome (GOLPP) - Endocrinopathy (hypoT, hypoA) immune mediated -infectious - myasthenia gravis - polymyopathy - systemic lupus erythematosus - toxins (lead; organophosphates)
A congenital form of laryngeal paralysis has been reported in what dog breeds…….?
- Bouviers des Flandres
- Siberian Huskies
- Bull terriers
- White coated german shepher dogs
Congenital laryngeal paralysis-polyneuropathy complexes have been described in….?
Dalmations, rottweilers, leonberger dogs, and pyrenean mountain dogs
What are the clinical signs of a dog with laryngeal paralysis?
- arytenoid cartilages and vocal folds remain in paramedian position during inspiration, and upper airway obstruction is
- noisy inspiration and exercise intolerance
- early signs = voice change, mild cough, and gagging.
- severe = resp distress, cyanosis, and collapse +/- dysphagia.
Signs are worsened by exercise, environmental temperature and/or humidity.
What diagnostic tests should be performed for dogs with laryngeal disease?
- physical exam
- ortho and neurological examinations
- CBC
- Biochem
- Urinalysis
- thyroid function -> to start thyroid treatment, but may not improve paralysis
- thoracic rads -> rule out aspiration pneumonia, identify megaoesophagus, pulmonary oedema, cardiac or lower airway abnormalities
- laryngeal exam
What is needed to achieve definitive diagnosis of laryngeal paralysis?
- examination of larynx to document lack or Raytheon I’d abduction during inspiration.
- laryngoscopes, oral video-endoscopic laryngoscopes, trans nasal laryngoscopes (TNL), ultrasound (US, echo), or CT.
- anaesthetic agents can produce false positives
How is acute respiratory distress managed?
- oxygen
- dexamethasone 0.1-1m/kg IV
- acepromazine 0.01-0.02 mg/kg IV
- Buprenorphine 0.005-0.01 mg/kg IV/butorphanol 0.1-0.25mg IV
- ET or tracheostomy if resp distress cannot be abated. Mucus production drastically increases, and it needs to be suctioned from tube.
What are some conservative long-term treatment options fo dogs with unilateral dysfunction?
- reduce daily exercise, owner education, weight loss, and sometimes anti inflammatory drugs
When is surgical intervention indicated?
- bilateral paralysis, poor QOL, severe clinical signs, and time of year
- unilateral arytenoid lateralisation is most used
How common is feline laryngeal disease, and who does it occur in?
- laryngeal disease uncommon in cats, but laryngeal paralysis accounts for 40% of cases.
- most often older cats (9-14years)
What is the cause of feline laryngeal disease?
Mostly unknown
- associated with trauma, neoplastic invasion or iatrogenic damage
How can feline laryngeal paralysis be diagnosed?
- laryngoscopes (direct or endoscopically), echolaryngography
How do cats present with unilateral paralysis?
- severe respiratory distress, often requiring surgery
- conservative management = weight loss and minimise excitement/exercise
- surgical treatment using unilateral arytenoid lateralisation
- MST = 150 days
What is laryngeal collapse?
What are the common breeds affected?
how is laryngeal collapse related to BOAS?
- consequence of chronic upper airway obstruction, most often associated with brachycephalic airway syndrome.
- English bulldogs, pugs, Boston terriers, and cavalier King Charles spaniels.
- Chronic upper airway obstruction increases airway resistance and negative intraglottic luminal pressure. This results in laryngeal collapse due to cartilage fatigue and degeneration.
- onset of laryngeal collapse is seen in brachycephalic dogs as young as 4.5-6 months of age.
What are the three stages of severity of laryngeal collapse?
Stage1: eversion of laryngeal succules into the glottis, increasing inspiratory effort, creating a vacuum, and causing mucosa of laryngeal succules to collapse
Stage 2: cuneiform process of arytenoid cartilage lose rigidity and collapse into laryngeal lumen. The aryepiglottic folds can collapse ventromedially.
Stage 3: Corniculate process o arytenoid cartilage fatigues and collapses toward midline, causing complete laryngeal collapse.
How is laryngeal collapse diagnosed?
- ## oral exam under heavy sedation or light plane of general anaesthesia without intubation.
How is laryngeal collapse treated?
- surgical treatment = resection of everted laryngeal succules is simple as succules are grasped with allies tissue forceps, and transcend with metzenbam scissors.
- early stage of collapse is possible, but later stages are limited.
- stage 2 & 3 dogs benefit from surgical removal of everted laryngeal succules, reduction of soft palate and correction of stenosis nares.
- unilateral arytenoid laryngoplasty has reasonable long-term outcomes
How does laryngeal stenosis occur?
- acquired laryngeal stenosis occurs following bilateral ventriculocordectomy through oral approach which leads to laryngeal webbing from scar tissue formation (cicatrix) as mucosal defects are left to heal by second intention.
- other causes include traumatic tracheal intubation, foreign body, caustic trauma.
What tumours of the larynx have been reported in dogs?
- rhabdomosarcoma
- squamous cell carcinoma (+ lymphoma is most common in cat)
- adenocarcinoma
- Osteosarcoma
- chondrosarcoma
- chondroma
- myxochondroma
- lipoma
- Fibrosarcoma
- undifferentiated carcinoma
- extramedullary plasmacytoma, and MCT
What is the prognosis of laryngeal tumors
- guarded
- few reports on treatment-> mostly prednisolone, chemotherapy and permanent tracheostomy
What is inflammatory laryngeal disease? How is it diagnosed?
- uncommon non neoplastic condition of arytenoid cartilages
- granulomatous, lymphocytic-plasmacytic, or eosinophilic
- biopsy of the mass is crucial to differentiate disease from neoplasia
- treatment of inflammatory laryngeal disease is palliative: debulking the mass, steroid therapy, or permanent tracheostomy. Permanent tracheostomy has been associated with higher mortality in cats with inflammatory laryngeal disease than in cats undergoing permanent tracheostomy for any reason.
