larynx: clinical

Question 1

how do the vocal cords appear when seen in laryngoscopy? why?

Answer 1

pearly white avascular appearance

the mucosa is firmly attached to the vocal ligament without any intervening submucosa

Question 2

do the vocal cords become oedematous during upper respiratory tract infections? why?

Answer 2

no

absence of intervening submucosa = no fluid can accumulate underneath the vocal cords

Question 3

what will damage to recurrent laryngeal nerve result in? why?

Answer 3

recurrent laryngeal nerve innervates muscles moving vocal cords
damage = paralysis to vocal cords + hoarseness of voice

Question 4

how do patients with UNIlateral recurrent laryngeal nerve palsy present?

Answer 4

initially: voice weak, paralysed vocal cords can’t ADduct fully to meet normal unaffected vocal cord on the other side
within a few weeks: contralateral fold (chord) crosses the midline to meet (paralysed) vocal cord and compensates

Question 5

how do patients with bilateral paralysis of the vocal chords present?

Answer 5

causes voice to be almost absent

vocal chords take up more ADducted position than normal resting position

Question 6

why do patients with bilateral paralysis of vocal chords result in stridor?

Answer 6

vocal cords cannot be ABducted for respiration (can’t pull vocal chords apart, so rima glottis becomes severely reduced)
high-pitched, turbulent air flow in larynx / LOWER down in bronchial tree
usually inspiratory, but can be expiratory or biphasic
both vocal cords assume PARAMEDIAN position

Question 7

with progression of recurrent laryngeal nerve lesion, which movement is loss first?

Answer 7

ABduction of vocal ligaments lost before ADduction
(harder to pull vocal ligaments apart by Posterior cricoarytenoid muscles, adduction by lateral cricoarytenoid)
both innervated by recurrent laryngeal branch of vagus

Question 8

following surgery, does adduction or abduction of vocal chords return first?

Answer 8

ADduction before abduction

Question 9

what does paralysis of superior laryngeal nerve result in?

Answer 9

anaesthesia of superior laryngeal mucosa and cricothyroid muscle
loss of protective mechanism designed to keep foreign bodies out of larynx and produces a monotonous voice

Question 10

why does a superior laryngeal nerve palsy cause monotonous voice?

Answer 10

palsy changes the pitch of the voice and causes an inability to make explosive sounds due to paralysis of the cricothyroid muscle

Question 11

how do surgeons avoid injury to the external branch of superior laryngeal nerve during thyroidectomy?

Answer 11

the superior laryngeal artery is ligated superior to the gland where it is not closely related to the nerve

Question 12

what is the piriform fossa a common site for?

Answer 12

where foreign bodies entering the pharynx can become lodged

Question 13

how can the piriform fossa be viewed and what does it look like / act?

Answer 13

larynx tilting up and epiglottis down

fossa is pear shaped and acts as a funnel

Question 14

what happens if sharp objects pierce the mucous membrane of piriform fossa (lateral to laryngeal inlet)?

Answer 14

nerve damage can occur:

superior laryngeal nerve (especially internal laryngeal branch - sensory to supraglottic)

Question 15

what is the epiglottic vallecula?

Answer 15

a depression from folds (vallecula) just behind the root of the tongue, but in front of epiglottis
(These depressions serve as “spit traps”; saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex)

Question 16

what is the clinical significance of vallecula?

Answer 16

objects can frequently become lodged

Question 17

aside from the vallecula, where else can objects become lodged?

Answer 17

1. piriform fossa (lateral to laryngeal inlet)

2. inferior end of the laryngopharynx (narrowest part of pharynx) - commonly to be removed by pharyngoscope

Question 18

how can a pharyngeal pouch develop?

Answer 18

when there is posterior herniation of pharyngeal mucosa between the 2 parts of the inferior pharyngeal constrictor (thyropharyngeus + cricopharyngeus) at their posterior margin (Killian’s dehiscence)

Question 19

what causes a pharyngeal pouch?

Answer 19

weakened inferior pharyngeal constrictors OR due to incoordination of the pharyngeal phase of swallowing

Question 20

what can a pharyngeal pouch cause?

Answer 20

dysphagia
sense of lump in back of neck
regurgitation
cough
halitosis (bad breath)

Question 21

what can be injured in thyroid surgery?

Answer 21

superior laryngeal and recurrent laryngeal nerves

removal parathyroid glands - affect Ca2+ regulation

Question 22

which is more common of hypopharyngeal / laryngeal carcinoma?

Answer 22

laryngeal carcinoma

Question 23

what happens in hypopharyngeal (laryngopharynx) carcinomas?

Answer 23

uncommon disease
pushes forward on the larynx (laryngopharynx posterior to larynx)
often from piriform fossa (lateral to laryngeal inlet on laryngopharynx)

Question 24

what is laryngeal carcinoma related to?

Answer 24

smoking and alcohol

Question 25

what is the prognosis for laryngeal carcinoma?

Answer 25

poor prognosis in subglottic (inferior to vocal cords, superior to trachea), but good prognosis in glottis (vocal cords)

Question 26

how are patients likely to present with laryngeal carcinoma?

Answer 26

dysphagia (pharynx - to oesophagus, compressing larynx)
odynophagia (pain on swallowing - pharyngeal peristalsis to oesophagus)
otalgia (referred pain - vagus)
hoarseness of voice (recurrent laryngeal nerve)
coughing (aspiration, haemoptysis)
weight loss (cachexia)
smoking history (pack/years)

Question 27

how will patients with laryngeal carcinoma present upon examination?

Answer 27

loss of laryngeal crepitus (felt rather than heard - from holding onto prominence of epiglottis and moving posterior against cervicla vertebrae)
occurs due to fixed larynx and cervical lymph node metastasis

Question 28

how do you investigate a laryngeal carcinoma?

Answer 28

barium swallow
CT/MRI
direct pharyngo-laryngo-oesophagoscopy
biopsy