Pathologies of the Larynx & Trachea – Exam Summary

Larynx – Functions & Position

• Protects airway during swallowing
• Respiration
• Phonation
• Chest fixation
• Adult level C3-C6; infant C2-C3 (descends with growth)

Framework – Cartilages

• Unpaired: Thyroid (largest; Adam’s apple), Epiglottis (leaf-shaped), Cricoid (complete ring)
• Paired: Arytenoid, Corniculate, Cuneiform

Ligaments & Membranes

• Ligaments (to thyroid cartilage): Thyroepiglottic, Vestibular (false cord), Vocal (true cord)
• Extrinsic membranes: Thyrohyoid, Cricothyroid, Cricotracheal
• Intrinsic membranes: Conus elasticus, Quadrangular membrane, Aryepiglottic folds

Muscles

• Extrinsic: suspend larynx (suprahyoid & infrahyoid groups)
• Intrinsic
– Open/close glottis: Posterior & lateral crico-arytenoids, transverse & oblique arytenoids
– Tension: Cricothyroid, Thyro-arytenoid, Vocalis
– Inlet shape: Aryepiglottic, Thyroepiglottic

Subsites

• Supraglottis – epiglottis to true cords
• Glottis – true cords + anterior/posterior commissures
• Subglottis – 5\,\text{mm} below cords to first tracheal ring

Vascular & Neural Supply

• Arteries: superior & inferior thyroid branches, cricothyroid branch
• Veins: superior & inferior thyroid → IJV / brachiocephalic
• Nerves (Vagus):
– Internal laryngeal – sensory above cords
– External laryngeal – motor to cricothyroid
– Recurrent laryngeal – motor to all other muscles; sensory below cords

Pediatric Larynx

• Higher, reaches soft palate during swallow
• Soft, easily collapsible cartilages; omega epiglottis
• Small, conical; cricoid the narrowest point
• Loose submucosa → rapid edema & obstruction

Trachea – Key Facts

• Begins below cricoid (level C6) → carina at T5 (to T6 in inspiration)
• Length 10\,\text{cm} (neck 5\,\text{cm} + thorax 5\,\text{cm}); diameter 2\,\text{cm}
• 15!–!20 C-shaped hyaline rings; membranous posterior wall
• Blood: inferior thyroid & bronchial arteries; venous to inferior thyroid vein
• Innervation: mucosa – Vagus/Recurrent; smooth muscle – sympathetic trunk

Key Laryngeal Symptoms

• Hoarseness
• Stridor
• Dyspnea
• Cough ± hemoptysis
• Dysphagia

Hoarseness – Core Points

• Requires: normal cord approximation, size, stiffness, vibration
• Mechanisms: masses/fixation, paralysis/edema, fibrosis
• Acute (<2 wk): viral laryngitis, irritants; self-limiting → voice rest, hydration • Chronic (>2 wk): reflux, nodules/polyps, papillomatosis, malignancy, neuro, smoking → treat cause; exclude cancer

Vocal Cord Nodules

• “Singer’s/Screamer’s” nodes – bilateral at anterior 1/3 of cords
• Due to voice abuse → edema → fibrosis
• Sx: hoarseness, throat discomfort
• Tx: voice rest, speech therapy, excision if persistent

Stridor – Essentials

• Turbulent airflow through partial obstruction
• Inspiratory (supraglottis), biphasic (glottis/subglottis), expiratory (trachea/bronchi)
• Congenital causes: choanal atresia, laryngomalacia, web, subglottic stenosis, VC paralysis
• Acquired: epiglottitis, croup, FB, papillomatosis, tumors, abscess
• Management – urgent airway assessment, identify & treat cause (imaging, endoscopy, surgery/tracheostomy as needed)

Recurrent Respiratory Papillomatosis (RRP)

• HPV 6 / 11; peripartum transmission
• Juvenile type (ages 3!–!5) more aggressive
• Sx: hoarseness, stridor, cough, dyspnea
• Dx: laryngoscopy – warty lesions; biopsy
• Tx: repeated microlaryngoscopic/CO₂ laser debulking; adjuvants (cidofovir, indole-3-carbinol, quadrivalent HPV vaccine)

Laryngitis

• Acute: viral URTI ± bacterial; alcohol, smoke, voice abuse
– Sx: hoarseness, raspy voice, dry cough, sore throat; no dyspnea
– Tx: voice rest, steam, analgesics, ± antibiotics
• Epiglottitis (H. influenzae B)
– Rapid onset, high fever, drooling, inspiratory stridor, "tripod" posture, no cough
– Thumb sign on lateral X-ray
– Secure airway (intubation/trach), IV ceftriaxone, steroids, humidified O₂
• Croup / Acute LTB (parainfluenza)
– Age 6\text{mo}–6\text{yr}, barking cough, hoarseness, steeple sign (AP X-ray)
– Tx: steroids, humidification, O₂; intubate if severe

Foreign Body Aspiration (FBA)

• Peak 1!–!3 yr; peanuts, seeds, metals
• Phases: initial choke → asymptomatic → complications
• Sx: sudden cough, wheeze, stridor, voice change
• Dx: history, neck/chest X-ray, CT; rigid bronchoscopy = gold standard
• Tx: Heimlich (pre-hospital), rigid bronchoscopy removal; antibiotics/steroids if needed

Upper Airway Obstruction (UAO)

• Narrowest point: subglottis (child) / glottis (adult)
• Hallmark = stridor; plus dyspnea, drooling, hoarseness
• Evaluation: X-ray (thumb/steeple), CT/MRI, endoscopy, ABG
• Management
– Medical: O₂, humidify, steroids, antibiotics, cautious intubation
– Surgical: cricothyrotomy (emergency), tracheostomy (definitive bypass, toileting, prolonged ventilation)

Tracheostomy – Key Facts

• Creates skin–trachea stoma (Jackson safety triangle)
• Indications: bypass UAO, bronchial toilet, prolonged ventilation, assist respiration
• Complications
– Immediate (0–6 h): hemorrhage, false passage, tube loss
– Early (6–72 h): dislodgement, surgical emphysema, pneumothorax, infection
– Late (>72 h): stenosis, tracheo-arterial/oesophageal fistula, difficult decannulation