Vocal Cord Dysfunction

The experience of VCD symptoms:

“I am getting a lot of spasms…and it’s really difficult”
Video provided by Dr. Joy Lee, Alfred Hospital, with permissions.

Vocal Cord Dysfunction  (VCD) can be defined as “involuntary and episodic closure of the vocal folds during inspiration which leads to symptoms of dyspnea, cough, dysphonia, and stridor”. Vocal Cord Dysfunction has been referred to by many different names in the literature. It is commonly referred to as “paradoxical vocal fold movement” (PVFM) or “inducible laryngeal obstruction (ILO)”. VCD is part of the spectrum of dysfunctional larynx which includes chronic cough, muscle tension dysphonia and globus pharyngeus.

VCD usually occurs during inspiration, but may also occur during expiration. It may be accompanied by a sensation of choking and suffocating, throat or chest tightness. Symptoms are often triggered quickly and resolve quickly once the triggering stimulus is removed.

VCD should be considered when other respiratory causes for symptoms are excluded or are insufficient to explain the severity of the condition.

Differential diagnosis includes: asthma, anaphylaxis, laryngeal spasm and subglottic stenosis.

• In contrast with asthma, symptoms in VCD are often localised to the larynx, there is more difficulty with inspiration than expiration, and onset and resolution of dyspnoea episodes is rapid rather than sudden. VCD may co-exist with asthma or may be misdiagnosed as asthma. Symptoms of VCD can mimic asthma leading to an incorrect diagnosis of asthma and escalating treatment of asthma including inhaled and systemic corticosteroids.
• Subglottic stenosis usually results in increased symptoms during exercise.
• Voice symptoms can occur in asthma in the absence of VCD.
• VCD commonly co-occurs in chronic cough (Shembal et al. 2017).

There is no universal agreement on the definition or diagnosis of VCD and no standardised classification system. Some common subtypes described in the literature are:

• Idiopathic
• Co-occurring with chronic refractory cough
• Exercise induced (Newsham et al. 2002)
• Irritant induced (Perkner et al. 1998)
• Psychological stress-induced

Further research is needed to determine classification criteria and develop agreement on definition and diagnosis (Shembal et al. 2017).

The prevalence of VCD is difficult to estimate. It varies between studies and depends on the study population and setting.

• VCD has been reported in:
  • 50% of patients with chronic cough (Ryan et al. 2008)
  • 3-5% of patients with severe asthma (Kenn et al. 1997 AJRCCM)
  • Up to 30% of patients with difficult asthma (Radhakrishna et al. 2016)
  • 5-22% of patients requiring emergency care for dyspnea (Jain 1997)
  • 15% of US recruits assessed for asthma (Morris et al. 2002)
  • 5% of US Olympians (Rundell et al. 2003)
• Some literature suggests female predominance (2:1), and is also recognised in people with high levels of irritant exposure, elite athletes, and some military personnel (Morris et al. 2013).
• Further research is needed.

• Questionnaires (For more information see Resources – Comorbidity Components)

• Clinical observations include inspiratory dyspnoea, stridor, cough, dysphonia, and tension in the laryngeal region. These symptoms may be absent during quiet breathing but more obvious during physical activity or voice testing. There may be a disparity between pulmonary function testing and symptoms. For example, a patient may have normal baseline spirometry (FEV1, FVC, FEV1/FVC ratio) in the presence of symptoms of breathlessness. Inhaled bronchodilators are frequently ineffective in relieving symptoms or only effective if used in large doses (e.g. 6-8 puffs at a time).

• Objective tests:

Representative flow volume loop with flattened inspiratory curve (black arrow) following methacholine challenge. Reproduced with permission from the ©ERS 2018.  European Respiratory Journal Jan 2011, 37 (1) 194-200; DOI: 10.1183/09031936.00192809  (Kenn et al. 2011).

• Speech pathology treatment is the mainstay of intervention. It contains several components including:
  • Education on what VCD is, how it coexists with asthma and why it needs a different approach to asthma treatment
  • Reducing laryngeal irritation by reducing exposure to laryngeal irritants, desensitisation, hydration and reducing phonotraumatic vocal behaviours (Boris et al. 2002)
  • Symptom control exercises such as PVFM release breathing. Exercises are timed with asthma medication.
  • Psychoeducational counselling
  • Inspiratory muscle training
  • Treatment of co-existing laryngeal issues such as cough, globus and dysphonia
• Continuous positive airway pressure (CPAP) lowers expiratory flow and increases lung volume, opening the glottis to relieve dyspnea. CPAP also reduces the effort required for inspiration by establishing a favourable pressure gradient for inhalation (Shin et al. 2016).
• Botox injections into the vocal folds prevents release of acetylcholine at nerve terminals, with use previously demonstrated for the management of dystonias. Effects of injections may last up to 14 weeks (Perez et al. 2012).
• Neuromodulating medication, such as pregabalin and gabapentin has been reported in the chronic cough literature (Ryan et al. 2012, Vertigan et al. 2016) and has been used to treat VCD where laryngeal hypersensitivity is suspected. More research is required to determine effectiveness in VCD.

• Vocal cord dysfunction is an important comorbidity in asthma. It can mimic asthma leading to inappropriate escalation in asthma treatment.
• Vocal cord dysfunction should be considered as a differential diagnosis or co-morbid in patients with severe asthma.
• Speech pathology treatment is effective in relieving symptoms.