Voice Disorders

Anatomy & Physiology - Voice Box Basics

• Larynx (Voice Box): Airway protection; phonation.
  • Cartilages: Unpaired (Thyroid, Cricoid, Epiglottis); Paired (Arytenoids, Corniculates, Cuneiforms).
• Vocal Cords:
  • True Vocal Cords (TVC): Mucosa, Reinke's space, vocalis m.; vibrate for voice.
  • False Vocal Cords (FVC): Superior to TVC; protective.
• Nerve Supply:
  • Superior Laryngeal N. (SLN): Internal br. (sensory above TVC), External br. (motor to Cricothyroid - pitch control).
  • Recurrent Laryngeal N. (RLN): Motor to all other intrinsic muscles; sensory below TVC.

⭐ RLN supplies all intrinsic laryngeal muscles except Cricothyroid (by External SLN).

Evaluation - Voice Detective Work

• Patient History:
  • Onset, duration, progression, vocal load (occupation/habits)
  • Associated: Pain, dysphagia, reflux, cough, trauma
  • Lifestyle: Smoking, alcohol
• Voice Assessment:
  • Subjective: Voice Handicap Index (VHI)
  • Perceptual: GRBAS scale (Grade, Roughness, Breathiness, Asthenia, Strain)
• Laryngeal Examination:
  • Flexible Nasopharyngolaryngoscopy (NPL) or Rigid Laryngoscopy
  • Stroboscopy: Essential for mucosal wave, vibration.

  ⭐ Stroboscopy differentiates organic lesions (nodules, polyps affecting wave) from many functional dysphonias (often normal/hyperfunctional patterns).

• Objective Analysis (if needed):
  • Acoustic: $F_0$, jitter, shimmer, Harmonics-to-Noise Ratio (HNR)
  • Aerodynamic: Airflow, phonation threshold pressure
• Further Investigations (selected cases):
  • Imaging (CT/MRI): Suspected tumor, deep spread, paralysis cause
  • Laryngeal EMG: Vocal fold mobility disorders

Benign Lesions & Inflammatory - Vocal Villains

• Vocal Nodules (Singer's/Screamer's Nodules): Bilateral, symmetric, at junction of anterior 1/3 & middle 1/3 of true vocal cords (mid-membranous fold). Cause: chronic vocal abuse. Rx: voice rest, speech therapy; rarely surgery.
• Vocal Polyps: Usually unilateral; can be sessile or pedunculated. Cause: vocal trauma, smoking, GERD. Rx: voice rest, microlaryngosurgery for persistent polyps.
• Reinke's Edema (Polypoid Corditis): Diffuse, bilateral, floppy edema in Reinke's space (superficial lamina propria). Cause: SMOKING (classic), chronic vocal abuse, hypothyroidism. Voice: low-pitched, husky. Rx: smoking cessation, voice therapy, surgery if severe.

  ⭐ Reinke's Edema is strongly associated with smoking, especially in middle-aged women, leading to a characteristic deep, husky voice.

• Vocal Cord Cysts: Unilateral, submucosal, intracordal; mucous retention or epidermoid. Rx: microlaryngosurgery.
• Contact Ulcers/Granulomas: Posterior larynx, on medial surface of arytenoids. Cause: vocal abuse (e.g., hard glottal attack), GERD, intubation trauma. Rx: voice therapy, anti-reflux (PPIs), rarely surgery.
• Laryngitis:
  • Acute: Viral most common. Sudden onset hoarseness. Rx: voice rest, hydration, steam inhalation.
  • Chronic: Due to irritants (smoking, pollution), GERD, chronic vocal abuse. Rx: eliminate cause, voice therapy.

Neuro & Functional - Cord Control Chaos

• Vocal Cord Palsy/Paralysis:
  • Etiology: Recurrent Laryngeal Nerve (RLN) injury (thyroidectomy, lung Ca, aortic aneurysm), CNS lesions.
  • Unilateral: Hoarseness, breathy voice, diplophonia. Cord positions: median, paramedian, lateral (cadaveric).
  • Bilateral:
    • Adductor (midline): Severe dyspnea, stridor. Airway emergency!
    • Abductor (lateral): Aphonia, aspiration.
  • 📌 RLN Vulnerability: Long course, esp. left RLN.
• Spasmodic Dysphonia (SD): Task-specific focal laryngeal dystonia.
  • Adductor SD: Strained, choked voice breaks.
  • Abductor SD: Breathy, weak, whispered voice breaks.
  • Treatment: Botulinum toxin (Botox) injections.

  ⭐ Spasmodic Dysphonia is often misdiagnosed as MTD; laryngeal EMG can aid diagnosis.

• Muscle Tension Dysphonia (MTD): Excessive perilaryngeal muscle activity.
  • Primary: No organic lesion. Secondary: Compensatory.
  • Voice: Strained, hoarse, vocal fatigue.
  • Treatment: Voice therapy.
• Functional Aphonia/Dysphonia: Psychogenic; sudden onset, normal vegetative functions (cough, laugh).
  • Treatment: Voice therapy, psychological support.
• Laryngeal Tremor: Rhythmic laryngeal muscle movements; often with essential tremor. Voice: quavering.

High‑Yield Points - ⚡ Biggest Takeaways

• Hoarseness: primary symptom of laryngeal disease.
• Laryngoscopy (indirect/flexible) is essential for diagnosis.
• Vocal nodules: bilateral, voice abuse, junction of anterior 1/3 & posterior 2/3.
• Vocal polyps: usually unilateral, from acute vocal trauma or smoking.
• Reinke's edema: diffuse swelling, smoking-related, deep husky voice.
• Persistent hoarseness >3 weeks in smokers: suspect laryngeal SCC.
• Unilateral vocal cord palsy: breathy voice; bilateral: stridor risk.