Vocal cord dysfunction (VCD) is a condition affecting the vocal cords. It is characterized by abnormal closure of the vocal folds, which can result in significant difficulties and distress during breathing, particularly during inhalation.
Due to the similarity in symptoms, VCD attacks are often mistaken for asthma attacks or laryngospasms. Symptoms of VCD are not always present. Rather, they often occur as episodic "attacks," where the patient will be symptomatic for a short period. Although several contributing factors have been identified, the exact cause of VCD is unknown.
Diagnosis of VCD may include a series of evaluations, including pulmonary function tests, medical imaging, and the evaluation or visualization of the vocal folds during an episode through the use of videolaryngoscopy. Such evaluations can also help to rule out other conditions that can affect the upper and lower airways. Treatment of VCD often combines behavioral, medical, and psychological approaches, most often including an otolaryngologist, a psychologist, and a speech-language pathologist. Although information on the incidence and prevalence of VCD is limited, it is known to occur most frequently in young women.
Signs and symptoms Many of the symptoms are not limited to the disorder, as they may resemble a number of conditions that affect the upper and lower airways. Such conditions include asthma, angioedema, vocal cord tumors, and vocal cord paralysis.Benninger C; Parsons JP; Mastronarde JG (2011-01-01). "Vocal cord dysfunction and asthma.". Current Opinion in Pulmonary Medicine. 17 (1): 45–9. ISSN 1070–5287.
People with vocal cord dysfunction often complain of "difficulty in breathing in" or "fighting for breath", which can lead to subjective respiratory distress, and in severe cases, loss of consciousness. They may report tightness in the throat or chest, choking, stridor on inhalation and wheezing, which can resemble the symptoms of asthma. These episodes of dyspnea can be recurrent and symptoms can range from mild to severe and prolonged in some cases. Agitation and a sense of panic are not uncommon and can result in hospitalization.
Different subtypes of vocal cord dysfunction are characterized by additional symptoms. For instance, momentary aphonia can be caused by laryngospasm, an involuntary spasm of the vocal cords and a strained or hoarse voice may be perceived when the vocal cord dysfunction occurs during speech.
Many of the symptoms are not specific to vocal cord dysfunction and can resemble a number of conditions that affect the upper and lower airways.
Presentation
VCD can mimic asthma, anaphylaxis, collapsed lungs, pulmonary embolism, or fat embolism, which can lead to an inaccurate diagnosis and inappropriate, potentially harmful, treatment. Some cases of VCD are misdiagnosed as asthma, but are unresponsive to asthma therapy, including bronchodilators and steroids. Among adult patients, women tend to be diagnosed more often. Among children and teenage patients, VCD has been linked with high participation in competitive sports and family orientation towards high achievement.
Vocal cord dysfunction co-occurs with asthma approximately 40% of the time. This frequently results in a misdiagnosis of asthma alone. Even young children can tell the difference between an asthma attack (primarily difficulty exhaling) and a VCD attack (primarily difficulty inhaling). Knowing the difference between the two will help those who have both know when to use the rescue inhaler prescribed or when to use the breathing recovery exercises trained by a speech-language pathologist.
Episodes can be triggered suddenly or develop gradually and triggers are numerous. Primary causes are believed to be gastroesophageal reflux disease (GERD), extra-esophageal reflux (EERD), exposure to inhaled allergens, post-nasal drip, exercise, or neurological conditions that can cause difficulty inhaling only during waking. Published studies emphasize anxiety or stress as a primary cause while more recent literature indicates a likely physical etiology. This disorder has been observed from infancy through old age, with the observation of its occurrence in infants leading some to believe that a physiological cause such as reflux or allergy is likely. Certain medications, such as antihistamines for allergies, cause drying of the mucous membranes, which can cause further irritation or hypersensitivity of the vocal cords.
Potential comorbidities VCD has long been strongly associated with a variety of psychological or psychogenic factors, including conversion disorder, major depression, obsessive-compulsive disorder, anxiety (especially in adolescents), stress (particularly stress relating to competitive sports), physical and sexual abuse, post-traumatic stress disorder, panic attacks, factitious disorder and adjustment disorder.
Anxiety and depression may occur in certain patients as a result of having VCD, rather than being the cause of it. Psychological factors are important precipitating factors for many patients with VCD; although exercise is also a major trigger for episodes of VCD, some patients experience VCD co-occurring with anxiety regardless of whether or not they are physically active at the time of the VCD/anxiety episode. Experiencing or witnessing a traumatic event related to breathing (such as a near-drowning or life-threatening asthma attack, for example), has also been identified as a risk factor for VCD.
VCD has also been associated with certain neurologic diseases including Arnold-Chiari malformation, cerebral aqueduct stenosis, cortical or upper motor neuron injury (such as that resulting from stroke), amyotrophic lateral sclerosis (ALS), parkinsonism syndromes and other movement disorders. However, this association occurs only rarely. In addition, it has been associated with Ehlers-Danlos Syndromes, a group of connective tissue disorders.
Causes The exact cause of VCD is not known, and it is unlikely that a single underlying cause exists. Several contributing factors have been identified, which vary widely among VCD patients with different medical histories. Physical exercise (including, but not limited to, competitive athletics) is one of the major triggers for VCD episodes, leading to its frequent misdiagnosis as exercise-induced asthma. Other triggers include airborne pollutants and irritants such as smoke, dust, gases, soldering fumes, cleaning chemicals such as ammonia, perfumes, and other odors. Gastroesophageal reflux disease (GERD) and rhinosinusitis (inflammation of the paranasal sinuses and nasal cavity) may also play a role in inflaming the airway and leading to symptoms of VCD as discussed below.
Laryngeal hyperresponsiveness is considered the most likely physiologic cause of VCD, brought on by a range of different triggers that cause inflammation and/or irritation of the larynx (voice box). The glottic closure reflex (or laryngeal adductor reflex) serves to protect the airway, and it is possible that this reflex becomes hyperactive in some individuals, resulting in the paradoxical vocal fold closure seen in VCD. Two major causes of laryngeal inflammation and hyperresponsiveness are gastroesophageal reflux disease (GERD) and postnasal drip (associated with rhinosinusitis, allergic or nonallergic rhinitis, or a viral upper respiratory tract infection (URI)). Rhinosinusitis is very common among patients with VCD and for many patients, VCD symptoms are ameliorated when the rhinosinusitis is treated. GERD is also common among VCD patients, but only some experience an improvement in VCD symptoms when GERD is treated. Other causes of laryngeal hyperresponsiveness include inhalation of toxins and irritants, cold and dry air, episodic croup and laryngopharyngeal reflux (LPR).
Risk factors The following increases an individual's chances for acquiring VCD: Upper airway inflammation (allergic or non-allergic rhinitis, chronic sinusitis, recurrent upper respiratory infections) Gastroesophageal reflux disease Past traumatic event that involved breathing (e.g. near-drowning, suffocation) Severe emotional trauma or distress Female gender Playing a wind instrument Playing a competitive or elite sport
Diagnosis The most effective diagnostic strategy is to perform laryngoscopy during an episode, at which time abnormal movement of the cords, if present, can be observed. If the endoscopy is not performed during an episode, it is likely that the vocal folds will be moving normally, a 'false negative' finding.
Spirometry may also be useful to establish the diagnosis of VCD when performed during a crisis or after a nasal provocation test. With spirometry, just as the expiratory loop may show flattening or concavity when expiration is affected in asthma, so may the inspiratory loop show truncation or flattening in VCD. Of course, testing may well be negative when symptoms are absent.
Differential diagnosis The symptoms of VCD are often inaccurately attributed to asthma, which in turn results in the unnecessary and futile intake of corticosteroids, bronchodilators and leukotriene modifiers, although there are instances of comorbidity of asthma and VCD.
The differential diagnosis for vocal cord dysfunction includes vocal fold swelling from allergy, asthma, or some obstruction of the vocal folds or throat. Anyone suspected of this condition should be evaluated and the vocal folds (voice box) visualized. In individuals who experience a persistent difficulty with inhaling, consideration should be given to a neurological cause such as brain stem compression, cerebral palsy, etc.
The main difference between VCD and asthma is the audible stridor or wheezing that occurs at different stages of the breath cycle: VCD usually causes stridor on the inhalation, while asthma results in wheezing during exhalation. Patients with asthma usually respond to the usual medication and see their symptoms resolve. Clinical measures that can be done to differentiate VCD from asthma include: rhinolaryngoscopy: A patient with asthma will have normal vocal cord movement, while one with VCD will display vocal cord abduction during inhalation spirometry: A change in the measure following the administration of a bronchodilator is suggestive of asthma rather than VCD chest radiography: The presence of hyperinflation and peribronchial thickening are indicative of asthma, as patients with VCD will show normal results
Treatments
Once a diagnosis of VCD has been confirmed by a medical professional, a specific treatment plan can be implemented. If vocal cord dysfunction is secondary to an underlying condition, such as asthma, gastroesophageal reflux disease (GERD), or postnasal drip, it is important to treat the primary condition as this will help control VCD symptoms. Conventional treatments for VCD are often multidisciplinary and include speech-language pathology, psychotherapy, behavioral therapy, use of anti-anxiety and anti-depressant medications, medical interventions, and hypnotherapy. There is no uniform approach. The information from randomized, blinded studies is limited.
Behavioral approaches
Speech-language pathologists provide behavioral treatment for VCD. Speech therapy usually involves educating the client on the nature of the problem, what happens when symptoms are present, and then comparing this to what happens during normal breathing and phonation. Intervention goals target teaching a client breathing and relaxation exercises so that they can control their throat muscles and keep the airway open, allowing air to flow in and out.