Larynx - Upper Respiratory Tract

Larynx

·        Function: protect airway from saliva and food, voice production

·        Vocal chords shut during coughing, straining, lifting ® maximal splinting from thoracic muscles

·        Anatomy:

o  Recurrent laryngeal: maintains open vocal chords via abductor muscle. If damaged ® stridor. Rest of muscles supplied by superior laryngeal nerve

o   Pharynx: superior, middle and inferior constrictor muscles attach on the cervical spine at medium raphae

·        Paediatric problems:

o   Signs: stridor, feeding difficulties

o   Failure of canalisation ® severe (normally dies)

o   Laryngomalatica: Supra glottic structures floppy ® collapse on inspiration ® inspiratory stridor. Improves with ­muscle tone/innovation

o   Subglottic stenosis: congenital or trauma (eg too big a ventilation tube)

o   Croup:

§  = Laryngo-tracheo bronchitis.

§  Inspiratory and expiratory stridor, barking cough

§  If frequent, may have anatomical narrowing

§  Usually viral infection.  If severe, steroids ® ¯inflammation

o   Obstructive sleep apnoea:

§  Very different to adults: usually due to enlarged adenoids/tonsils – snore loudly

§  ®Failure to thrive, behavioural problems, etc

§  Obstructive apnoea up to age 7 ® take adenoids out

o   Epiglottis:

§  Symptoms: obstruction, sore throat, drooling, toxic/septicaemia

§  Cause: bacterial infection (eg H. Influenzae)

§  Medical emergency: can deteriorate quickly. Don‟t examine throat – may cause spasm and obstruct

§  Emergency treatment: Geudal airway and ambubag. If unsuccessful get a very experienced person to intubate. If unsuccessful cricothyroidotomy with 14 gauge needles

·        Tonsillitis:

o   Tonsils are not normal lymph nodes: don‟t have capsule or afferent vessels

o   Bulk of lymphoid tissue is in base of tongue

o   Decrease in size with age.  At 40 half the size as when 15

·        Foreign bodies:

o   Can‟t eat or drink.

o   In kids: 10-cent pieces, inhaled peanuts. Differential: asthma (cough and wheeze). If < 2 years old, do CXR and look for collapse distal to obstruction

o   In elderly with dentures: can‟t chew or feel unwell

o   Must take out: if stuck in gullet, will perforate within 7 days.  Can linger for months in lung

·        Vocal chords:

o   Papillomas: usually solitary. Very low incidence of malignant change. Laser them (usually repeatedly)

o   Nodules: usually bilateral. Keratinised lesions from chords banging together. Treatment: vocal rest, correct voice abuse

o   Polyps: usually unilateral.  Granulation tissue/inflammatory

o   Reincher‟s disease: in middle aged female smokers. Degenerative, gelatinous polyps of surrounding mucosa ® hoarse voice, obstruction. Cause unknown

·        Recurrent Laryngeal Palsy:

o   Usually left nerve: longer.  Right only goes round subclavian

o   40% idiopathic

o   Exclude: bronchogeneic cancer, mediastinal lymph nodes (eg lung or breast Ca), Ca of larynx, mononeuropathic infection

·        Voice disorders (Dysphonia, Aphonia):

o   Obstruction to vocal chord closure: vocal chord thickening/oedema, nodules, papilloma, ulcers, polyps

o   Larynx growths: leukoplakia, hyperkeratosis

o   Trauma: intubation, external

o   Paralysis: superior or recurrent laryngeal nerve

o   Vocal hyperfunction: spastic dysphonia, tension due to voice abuse (singers, teachers)

o   Presbyphonia: in the elderly

o   Other: chronic laryngitis ® mucosal atrophy, Parkinson‟s, Motor neuron disease, following laryngectomy

·        In all cases refer to speech-language therapy for assessment/management

Tumours of the Larynx

·        Benign non-neoplastic neck lumps:

o   Inflammatory:

§  Lymph nodes: anterior cervical for tonsillitis, jugular digastric for tongue

§  Atypical Tb (especially kids)

§  Deep Neck abscesses: para-pharyngeal or retro-pharyngeal abscesses (can track down into mediastinum)

o   Thyroglossal cysts: cysts in embryological track from tongue to thyroid (usually at level of hyoid)

o   Branchial cysts: ?embryological.  Like enlarged anterior node.  Contain lots of cholesterol

o   Pharyngeal pouch: Mucosa herniates out through triangle between the cricopharyngeus and thyropharyngeal muscles under pressure from swallowing when upper oesophageal sphincter doesn‟t relax properly. Catches food, becomes infected. Treatment: surgery

·        Laryngeal Nodule:

o   Due to trauma of vocal chords banging together ® oedema (early) ® scarring/granulation tissue (late)

o   Only on anterior 1/3^rd of vocal fold

o   Completely benign

o   Gravely voice

·        Laryngeal Papilloma:

o   Like sinonasal papillomas

o   Most commonly seen in children

o   Associated with HPV 6, 11

o   Tendency to recur: can become unmanageable ® airway obstruction

o   Benign ® squamous overgrowth

·        Laryngeal Carcinoma:

o   Presentation:

§  Presenting early: if affect vocal chords, invade recurrent pharyngeal nerve, front of mouth

§  Presenting late: supraglottic lesions due to airway obstruction or pain (Þ deeper), sinus (lots of space)

§  Dysphagia rare

·        90% are squamous cell carcinoma (like lung)

·        Mostly in males, smoking a major risk factor, also alcohol, radiation, family history, tend to be older (> 50)

·        Classification, prognosis and treatment depends on site (prognosis also depends on stage):

o   Glottic: 60%, on chords, maintained in larynx by cartilage. Treatment: radiotherapy unless spread through cartilage

o   Supraglottic: 30%, above chords, involves false chord. More aggressive, metastasise to cervical lymph nodes

o   Transglottic: < 5%, crosses from one chord to another

o   Infraglottic  < 5%, below chords, more aggressive

·        Don‟t usually metastasise elsewhere, but lymph node infiltration common

·        Treatment: radiotherapy (® dry mouth) +/- surgery (superficial, hemilaryngectomy, laryngectomy, laryngectomy +/- radical neck resection. Chemo has little effect against SCC (most of them). If laryngectomy then need a tracheostomy (® can‟t cough, ­infection, ¯humidification, etc)

 ·       Neonatal Acute Airway Problems

·         Choanal Atresia: failure of formation of nasal passages. Baby goes blue until someone opens the mouth. Can‟t pass NG tube. Can be unilateral

·         Congenital masses: nasal encephalocele and nasal dermoid. Care with nasal intubation. Beware the midline lesion

·         Pierre Robin Sequence: short jaw, cleft palate and tongue falls back and obstructs. Nurse prone. Associated with oligohydramnios

·         Subglottic Stenosis: due to intubation trauma in a preterm baby