Vocal cord dysfunction

Vocal cord dysfunction (VCD), also referred to as inducible laryngeal obstruction, is a functional disorder characterized by the inappropriate, transient closure of the vocal cords, most commonly during inspiration. It is more prevalent in female individuals than male individuals and is typically diagnosed in early to middle adulthood. VCD can be triggered by intrinsic factors such as GERD or respiratory infections, environmental irritants, psychological stressors, and exercise. Patients typically present with sudden, severe throat tightness, dyspnea, and inspiratory stridor, but no objective signs of hypoxia, and patients do not respond to traditional asthma treatment. Abnormal vocal cord adduction during respiration on flexible nasolaryngoscopy confirms the diagnosis. Breathing techniques and reassurance are the mainstays of management for acute episodes. Long-term management is typically multidisciplinary and includes trigger avoidance, management of associated conditions, speech therapy, and biofeedback.

• Prevalence
  • General population: 5–8% ^[1]
  • Up to 50% in patients with asthma ^[1]
• ♀ > ♂ (2–3:1) ^[1][2]
• Can occur at any age but most commonly diagnosed between 30 and 40 years of age ^[2]

Epidemiological data refers to the US, unless otherwise specified.

VCD is caused by inappropriate, transient closure of the vocal cords, most commonly during inspiration, but can also occur during expiration. ^[3]

Triggers ^[2][3]

• Exercise (exercise-induced laryngeal obstruction)
• Laryngeal irritation
  • GERD
  • Rhinosinusitis
  • Respiratory infections
  • Environmental irritants (e.g., cold air, chemicals)
• Psychiatric disorders (e.g., anxiety disorders, depressive disorders, conversion disorder)

• Typical features: usually sudden in onset, episodic, and can occur sporadically or in response to triggers ^[2][3][4]
  • Chest and/or throat tightness
  • Inspiratory stridor
  • Dyspnea without hypoxia ^[2]
  • Wheezing ^[1]
  • Voice changes (e.g., dysphonia) ^[1]
• Associated symptoms
  • Cough
  • Anxiety

Physical examination is typically normal between acute episodes. ^[1]

The criterion standard for diagnosing VCD is direct visualization of abnormal vocal cord motion on nasolaryngoscopy. Additional diagnostics are performed to exclude alternative diagnoses. ^[2]

Evaluate for VCD in patients with confirmed or suspected asthma who remain symptomatic despite treatment optimization. ^[2]

Nasolaryngoscopy ^[3][4]

• Indication: suspected VCD ^[3][4]
• Method
  • Flexible nasolaryngoscopy, ideally during an acute episode ^[2]
  • May be performed with or without provocation (i.e., exposure to triggers) ^[4]
• Finding: abnormal vocal cord adduction during respiration ^[4]

Nasolaryngoscopy may be normal in asymptomatic patients; a normal examination does not exclude VCD. ^[3][4]

Additional diagnostics

• Pulmonary function testing ^[2][4]
  • Indication: typically performed to exclude alternative diagnoses (e.g., asthma)
  • Findings in VCD
    • Flow-volume loops may reveal a flattened, truncated, or saw-tooth pattern on the inspiratory limb. ^[3]
    • The ratio of forced expiratory flow to forced inspiratory flow at 50% of forced vital capacity is typically ≥ 1. ^[2][3]
• Imaging
  • Chest x-ray: may be considered to evaluate for other causes of obstruction (e.g., masses) ^[2]
  • Multidetector dynamic CT: can be used to assess vocal cord motion noninvasively ^[1]

• Asthma
• Angioedema and anaphylaxis
• Vocal cord paralysis
• Infection (e.g., croup, epiglottitis)
• Foreign body aspiration
• Neck masses
• Anatomical airway abnormalities (e.g., subglottic stenosis, vocal cord polyps, laryngomalacia)

The differential diagnoses listed here are not exhaustive.

Acute management ^[3]

• Reassure patients that symptoms are typically self-limited and not life-threatening.
• Advise patients to perform breathing exercises during acute episodes. ^[2]
• Adjunctive treatments with limited evidence include: ^[1]
  • Benzodiazepines in selected patients (e.g., with anxiety as a trigger)
  • Heliox ^[2]
  • Noninvasive positive-pressure ventilation

Long-term management ^[2][3]

Management is typically multidisciplinary (e.g., pulmonology, otolaryngology, speech pathology, psychology). ^[1]

• Trigger avoidance
• Management of associated conditions (e.g., management of asthma, anxiety)
• Speech therapy
  • Voice therapy
  • Breathing techniques for vocal cord relaxation
• Biofeedback
• Botulinum toxin: reserved for severe, refractory VCD