Vocal Cord Dysfunction

Vocal cord dysfunction is inappropriate, intermittent adduction (closure) of the vocal folds during inspiration (paradoxical vocal fold motion), and sometimes during expiration, which narrows the glottic airway and causes episodes of breathlessness, inspiratory noise (stridor) and throat tightness. It is commonly misdiagnosed as asthma.

• Prevalence: about 5 to 10% of patients referred with severe or refractory asthma have this condition, and it coexists with asthma in about 30 to 50% of cases. It affects mainly females (about 2 to 3 times) aged 20 to 40 years, and adolescent athletes.
• Triggers: exercise, irritants (smoke, perfumes, cleaning products, cold air), laryngopharyngeal reflux, postnasal drip and chronic rhinosinusitis, emotional stress and anxiety, speech and singing, upper respiratory infection, and aspirating small volumes of secretions.
• Mechanism: laryngeal hypersensitivity and a sensory motor abnormality, with irritant or reflux stimulation of the laryngeal mucosa and altered central control of the laryngeal muscles. Psychological factors (anxiety, trauma, perfectionism) contribute in some patients, but it is not a psychiatric condition by itself.
• Associated conditions: asthma, gastro oesophageal reflux, rhinitis and sinusitis, anxiety, depression, trauma and abuse history, neurological disease (brainstem lesion, Chiari malformation, motor neurone disease), and after intubation or upper airway surgery.
• Chronic misdiagnosis leads to unnecessary oral corticosteroid use, hospital visits, intubation, and a delay in diagnosis of 4 to 5 years on average.

• Sudden onset episodes of breathlessness, a tight throat, a choking sensation, inspiratory wheeze or stridor (loudest over the neck), hoarseness, cough, and throat clearing. Episodes last from minutes to 30 minutes, then resolve on their own, and are often worse on inspiration. Symptoms are rarely present during sleep.
• The patient feels the problem is in the throat or neck, and may point to the larynx. Oxygen saturation is normal during episodes (95 to 100%), and cyanosis is rare.
• Little or no response to bronchodilators, inhaled corticosteroids, or oral steroids. Symptoms can occur with exercise, usually at peak effort, resolving within 2 to 5 minutes of stopping, unlike exercise induced bronchoconstriction, which peaks after exercise.
• Examination: normal between attacks. During episodes, loud inspiratory stridor (heard over the neck, and louder than over the chest), and a voice that is strained or breathy, with a normal chest examination (transmitted upper airway sounds).
• Differential diagnosis: asthma, exercise induced bronchoconstriction, subglottic and tracheal stenosis, laryngomalacia (children), vocal fold paralysis, laryngeal tumour, foreign body, anaphylaxis, epiglottitis, tracheomalacia, goitre, angioedema, panic disorder, and dysfunctional breathing.
• Red flags: stridor at rest, hoarseness for more than 3 weeks, haemoptysis, a neck mass, dysphagia, weight loss, recent neck surgery or intubation, progressive symptoms, neurological signs, fever, and drooling.
• Complications: repeated emergency visits and intubation, steroid related adverse effects, anxiety, avoidance of exercise, voice problems, and a rare progression to respiratory failure.

• Clinical suspicion with a typical history, then confirmation by direct visualisation of the larynx during symptoms.
• Flexible nasolaryngoscopy during an episode, or after provocation (exercise, irritant inhalation, or reflux), shows adduction of the anterior two thirds of the vocal folds on inspiration, with a posterior diamond shaped chink. A normal examination between episodes does not exclude the diagnosis.
• Spirometry with flow volume loop: flattening or truncation of the inspiratory limb (the extrathoracic variable obstruction pattern) during an episode, with a normal expiratory limb, in contrast to the scooped expiratory limb in asthma. Spirometry is often normal between attacks.
• Assess for asthma with spirometry, bronchodilator reversibility, fractional exhaled nitric oxide, and methacholine or mannitol challenge, because both conditions often coexist.
• Evaluate triggers: assessment of reflux (symptom history, or an 8 week course of acid suppression), upper airway examination for rhinitis and sinusitis, an occupational and environmental history, and screening for anxiety and depression.
• Imaging, such as CT or MRI of the neck, chest and brain, is used for atypical features, stridor with neurological signs, or when structural disease is suspected.
• Laryngeal electromyography, if there is vocal fold paralysis or neurological disease.

• Explain the diagnosis, and the reasons for the symptoms, reassuring the patient that the airway is not blocked and that episodes self-resolve.
• Speech and language therapy (laryngeal control therapy), the first line treatment, in 3 to 6 sessions with home practice:
  • Education about laryngeal function and triggers.
  • Relaxed throat breathing: breathe in through the nose or through pursed lips with a sniff, relax the shoulders, neck and jaw, and breathe out slowly with a hissing "sss" or "fff" sound for 5 to 8 seconds, using the abdomen.
  • Rescue technique for an attack: stop the activity, sit upright, relax the throat, pant gently or use "pursed lip" breathing, and take quiet slow breaths until the episode resolves.
  • Voice and cough control: throat clearing reduction, hydration, and avoidance of voice strain.
• Treat triggers and coexisting disease:
  • Gastro oesophageal and laryngopharyngeal reflux: omeprazole 20 to 40 mg orally once or twice daily 30 minutes before meals for 8 to 12 weeks, with an alginate (sodium alginate and potassium bicarbonate 10 to 20 mL after meals and at bedtime), dietary changes and head-of-bed elevation.
  • Rhinitis and postnasal drip: fluticasone propionate nasal spray 50 micrograms per spray, 2 sprays into each nostril once daily, saline irrigation, and a second generation antihistamine such as cetirizine 10 mg once daily.
  • Asthma: confirm by testing and step down inhaled corticosteroids if asthma is not proven.
  • Irritant avoidance: avoid smoke, aerosols, perfumes and cleaning chemicals, and use a mask for workplace exposure.
• Psychological support: cognitive behavioural therapy for anxiety and panic, relaxation training, and treatment of trauma. Sertraline 25 mg daily, increased to 50 to 100 mg daily, for comorbid anxiety or depression.
• Acute episode:
  • Calm reassurance in a quiet environment, sit upright, and coach slow, relaxed breathing: in through the nose or pursed lips, and out slowly for 5 to 8 seconds. The attack usually settles within 5 to 30 minutes.
  • Lorazepam 0.5 to 1 mg sublingually or orally for severe anxiety, as a single dose when the diagnosis is secure, avoiding repeated use.
  • Nebulised ipratropium or salbutamol has no effect and delays correct treatment. Do not give oral steroids unless asthma is documented.
  • Continuous positive airway pressure (4 to 8 cm of water via a face mask), heliox (a helium and oxygen mixture at 70:30), or a short acting sedative can help in severe attacks in hospital. Intubation is rarely needed and should be avoided, because the larynx is normal.
• Refractory or severe cases (specialist care): botulinum toxin A injection into the thyroarytenoid muscles (2.5 to 5 units per side, under electromyographic or laryngoscopic guidance) in patients unresponsive to therapy. Repeat injections every 3 to 6 months. Hoarseness and breathy voice are temporary adverse effects.
• Exercise related episodes: breathing control during warm up and effort, nasal breathing at the start, pacing, and the rescue technique, with laryngeal control therapy.
• Special groups:
  • Children and adolescents: reassure, teach relaxed breathing and the rescue technique, avoid unnecessary asthma treatment, and involve the school and coach. Review triggers such as reflux and anxiety.
  • Athletes: continuous laryngoscopy during exercise to confirm, then training in breathing control, and psychological support.
  • Pregnancy: use non-drug treatment, omeprazole or alginates for reflux, and avoid botulinum toxin.
  • Elderly: investigate for neurological disease, laryngeal tumour and vocal fold paralysis.
  • Anxiety and trauma: integrate mental health care.
• Follow up: review at 4 to 6 weeks, and at 3 months. Refer to ENT for laryngoscopy, to speech and language therapy for laryngeal control therapy, to respiratory medicine for asthma assessment, and to mental health services for persistent anxiety or trauma.