Pathologies of the Larynx and Trachea

Larynx

  • Functions:
    • Protection of airway during swallowing
    • Respiration
    • Phonation
    • Fixation of chest
  • Adult larynx: C3-C6, Infants: C2-C3
  • Cartilages:
    • 3 single: Thyroid, Epiglottis, Cricoid
    • 3 paired: Arytenoid, corniculate, cuneiform
  • Thyroid cartilage: Largest, Adam's apple, hyaline
  • Cricoid: Complete ring, articulates with arytenoid
  • Epiglottis: Leaf-shaped, protects airway
  • Ligaments: Thyroepiglottic, Vestibular, Vocal
  • Membranes:
    • Extrinsic: Connects larynx to surrounding structures
    • Intrinsic: Connects laryngeal cartilages
      • Conus elasticus
      • Quadrangular membrane
      • Aryepiglottic folds
  • Muscles:
    • Extrinsic: Connect larynx to hyoid and trachea
    • Intrinsic: Interconnect laryngeal cartilages
      • Open/close glottis
      • Tension of vocal ligaments
      • Alter shape of laryngeal inlet
  • Subsites:
    • Supraglottis: Epiglottis to true vocal folds
    • Glottis: True vocal cords, anterior/posterior commissures
    • Subglottis: Inferior glottis to trachea ring 1
  • Blood Supply: Laryngeal branches of thyroid arteries
  • Innervation: Branches of Vagus Nerve
    • Internal Laryngeal Nerve: Sensory above vocal cords
    • External Laryngeal Nerve: Motor to cricothyroid
    • Recurrent Laryngeal Nerve: Sensory below vocal cords, motor to all other muscles
  • Child Larynx:
    • Higher position
    • Softer cartilages
    • Omega shaped epiglottis
    • Flat thyroid cartilage
    • Small and conical shape
    • Loose submucosal tissues

Trachea

  • Membranous/cartilaginous tube
  • C6 to T5
  • 10 cm long, 2 cm diameter
  • Anterolateral: incomplete cartilaginous rings
  • Posterior: membranous wall
  • 15-20 horseshoe-shaped cartilage
  • Blood supply: Inferior thyroid and bronchial arteries
  • Nerve supply: Vagus and RLN, sympathetic trunk

Laryngeal Symptoms/Signs

  • Hoarseness
  • Stridor
  • Dyspnea
  • Cough
  • Hemoptysis
  • Dysphagia

Hoarseness

  • Disorder of sound quality
  • Vocal cords:
    • Approximate properly
    • Proper size and stiffness
    • Vibrate regularly
  • Mechanism:
    • Loss of approximation
    • Size change
    • Stiffness change
  • Category:
    • Acute Onset
      • Local inflammation
      • Self-limiting
      • Treatment: voice rest, fluids
    • Chronic Onset:
      • >2 weeks
      • Etiology: reflux, polyps, nodules, malignancy
      • Treatment: stop smoking, treat etiology
  • Differential Diagnosis:
    • Acute viral laryngitis
    • Vocal cord nodules, polyps, cysts, papillomas
    • Vocal cord paralysis
    • Hypothyroidism
    • Rhinosinusitis
    • Laryngeal cancers
    • Laryngopharyngeal reflux
    • Recent intubation
    • Allergies
  • Systemic Diseases:
    • Hypothyroidism, Multiple sclerosis, Rheumatoid arthritis
    • Parkinson’s dx, Systemic lupus
    • Amyotrophic lateral sclerosis, Wegener’s granulomatosis
    • Myasthenia gravis, Sarcoidosis
    • Tremor disorders
    • Amyloidosis

Vocal Cord Nodules

  • Singer's/screamer's nodes
  • Benign growths
  • Voice abuse
  • Anterior 1/3 of vocal cord
  • Symptoms: hoarseness, otalgia
  • Treatment: voice rest, speech therapy, surgery

Stridor

  • Noisy respiration
  • Turbulent airflow
  • Inspiratory, expiratory, or biphasic
  • Aetiology:
    • Congenital: choanal atresia, laryngomalacia, subglottic stenosis
    • Acquired: epiglottitis, laryngitis, foreign bodies, papillomatosis, malignancies
  • Management:
    • History: onset, duration, relation to feeding
    • Physical Exam: respiratory distress, fever
    • Investigations: imaging, microlaryngoscopy, bronchoscopy
    • Treatment: directed at cause, surgical interventions

Recurrent Respiratory Papillomatosis (RRP)

  • Juvenile onset (JORRP) more severe
  • HPV 6 & 11
  • Peripartum transmission
  • Risk factors: firstborn, vaginal delivery, young mother
  • Symptoms: hoarseness, stridor
  • Diagnosis: laryngoscopy, biopsy
  • Treatment: surgical debulking, adjuvant therapy

Laryngitis

  • Inflammation of laryngeal mucous membrane
  • Types: acute, chronic
  • Acute:
    • Infectious or noninfectious
    • Etiology: URTI, alcohol, tobacco, trauma
    • Clinical Features: hoarseness, cough, discomfort
    • Progress: spontaneous resolution
    • Treatment: voice rest, steam, antibiotics

Acute Epiglottitis

  • Supraglottic structures
  • Rapid progression
  • Children 2-7yrs
  • Etiology: H. Influenza type B
  • Clinical Presentation: high fever, drooling, stridor, tripod position
  • Investigations: X-ray (thumb sign)
  • Treatment: intubation, IV antibiotics, steroids

Croup/Acute LTB

  • 6mo to 6yrs
  • Etiology: Viral, parainfluenza
  • Clinical features: Barking cough, hoarseness, stridor
  • X-ray: Steeple sign
  • Treatment: Steroids, humidification, oxygen
  • Differences between Acute Epiglottitis & ALTB(CROUP)
    • Appearance toxic and unwell vs well looking
    • Abrupt onset vs viral prodrome, slower
    • High fever (>38.5°C) vs moderate fever
    • Usually moderate-severe vs usually mild-moderate
    • Minimal or absent cough vs barking, seal-like quality
    • Unable to speak vs hoarse voice
    • Unable to swallow, drooling of saliva vs able to swallow

Foreign Body Aspiration

  • Clinical features depends on size, shape and character of FB
  • 3 clinical phases of FBA:
    • Initial phase (choking, gagging, paroxysms of coughing or airway obstruction)
    • Asymptomatic phase (symptoms subside when FB becomes lodged and reflexes fatigued)
    • Complication (haemoptysis, pneumonia, atelectasis, abscess)
  • Classic Triad
    • wheezing
    • coughing
    • dyspnea
  • Treatment:
    • Heimlich manoeuvre
    • Removal by direct laryngoscopy/ rigid bronchoscopy(gold standard)
    • Tracheostomy (laryngeal FB)
    • Systemic antibiotics / Steroids

Upper Airway Obstruction

  • Definition: Nose to carina
  • Narrowest region: Subglottic in children, glottic in adults
  • Etiology/Differential Diagnosis
    • Nasal Obs.; Tumors, Choanal atresia,FBs, Trauma(septal hematoma), Sinusitis
    • Rhinitis medicamentosa, Nasopharyngeal Obs.;Adenoid Hyp. Adenoiditis, Tumors, Cysts(encephalocele),
    • Pharyngeal Obs.: DNSIs,FBs,Tumors,Angioedema
    • Laryngeal and Tracheal Obs.: Epiglottitis, LTB, Trauma, FBs, Tumors, Laryngo/ tracheomalacia ,GERD
    • Subglottic stenosis,Tracheal compression, V.Cord paralysis
  • Clinical Features: Stridor, Dyspnea, Dysphagia, Coughing, Hoarseness
  • Investigations: Radiological, Endoscopy, Biochemical
  • Treatment:
    • Medical: ICU, Oxygen, Corticosteroids, Antibiotics, Intubation
    • Surgical: Cricothyrotomy, Tracheostomy

Tracheostomy

  • FUNCTION:
    • Alternate pathway for breathing
    • Improves alveolar ventilation
    • Protects the lower airway
    • Permits removal of secretions from the tracheobronchial tree
    • Permits administration of anesthesia
    • For IPPV
  • DISADVANTAGES:
    • Anosmia, Aphonia, Inability to lift heavy weights, Inability to swim, Inability to perform strenuous exercises, Risk of aspiration if a cuffed tube is not used
  • TYPES:
    • TIMING: Emergency/Elective tracheostomy
    • PURPOSE: Permanent/Temporary tracheostomy
    • POSITION: High/Mid/Low tracheostomy
  • Complications:
    • Immediate
    • Early
    • Late