Vocal cord dysfunction (VCD) is an abnormal adduction (movement towards the middle of the body) of vocal cords which causes airflow obstruction during the respiratory cycle.
The classic symptoms of VCD include wheezing, coughing, dyspnea, stridor, tightness of throat, a choking sensation, dysphonia, and cyanosis. These symptoms usually occur in other disorders as well, such as asthma, anaphylaxis, or pulmonary embolism, and for this reason it is very easy to make an inaccurate diagnosis, which might lead to inappropriate and even harmful treatment .
Anyways, the differential diagnosis of VCD includes the main signs of vocal cord swelling and vocal cord obstruction. Moreover, these are usually associated with a different modality of attack, which primarily consists in a difficulty in inhaling during VCD and a difficulty in exhaling during asthma. As VCD co-occurs with asthma in the 40% of the cases , this is a paramount difference to distinguish the two disorders. In the most severe cases, loss of consciousness can also be observed.
The VCD episodes might occur in a sudden manner or follow a gradual pattern of development. They are generally started by a number of triggers, which include gastroesophagel and extra-esophgeal reflux, exposure to inhaled allergens, physical exercise or strain, several neurological conditions, as well as anxiety and stress. They can also be started by the taking of certain medications, especially histamines which cause the mucus membranes to dry, thus inducing further irritation of vocal cords.
The diagnosis of VCD can be performed only after the exclusion of other potential conditions, or after negative response to the prescribed medications and treatments. The most effective technique to diagnose VCD is undoubtedly laryngoscopy, which allows to observe abnormal vocal cord movements during VCD attacks   , while spirometry can underline the occurrence of VCD through the presence of truncations or flattening in the inspiratory part of the flow-volume loop.
VCD can also be diagnosed through other tests as well. These include chest radiography, which is generally used to evaluate other pulmonary diseases, and laboratory tests like eosinophil count, serum IgE assay, arterial blood gases (ABC), C1 inhibitor and C4 level, which can be employed to exclude allergies, asthma and and other disorders.
VCD has to be treated with a multidisciplinary approach that involves the participation of different specialists and the use of different treatments. In the cases of inaccurate diagnosis it is important to stop the previous unnecessary treatment as soon as possible. A classical example of this situation is the use of steroids for misdiagnosed asthma, which might have severe long-term consequences such as growth retardation in children if not terminated in time.
With the help of specialists, an appropriate plan of treatment can be organized, based on measures like breathing exercises, behavioral therapy, use of anti-anxiety or antidepressant drugs, and hypnotherapy. The rule would be to personalize the VCD therapy according to the patient’s needs. A regimen with heliox, intermittent positive pressure ventilation and continuous positive airway pressure can be very useful in treating cases of acute VCD episodes. The most severe cases, instead, might need more extreme approaches, such as tracheotomy, to obtain temporarily relieve, and the use of botox, a neurotoxin protein employed to treat a number of medical problems , thanks to its ability to weaken muscles for period of three-four months  during episodes of spasms and dystonia .
In the phase of follow-up the patient undergoes a speech and relaxation therapy, to recover the voice and take control of the disorder. The prognosis after several weeks is usually good, provided that the patient have been following the opportune therapies and respecting the medication regime prescribed, with no new acute VCD attack that should be expected.
Although the etiology of VCD is still unclear, a number of factors have been associated with it. The first is the gastroesophageal reflux and laryngopharyngeal reflux, which provoke long-term irritations and damages, including scars on the throat and voice box. The second is the quality of the environment, which is full of new pollutants and toxic products. These substances trigger allergies, sinusitis, or recurrent viral infections responsible for the inflammation of the upper airways. This factor undoubtedly poses a serious challenge for physicians and experts, which have to cope with an increasingly larger range of new toxic and irritating materials requiring a constant updating. Strictly connected with this problem is the use of irritant fumes in the daily environment, like chlorine gases with large application in industrial and consumers products.
The etiology of VCD might also have physical and psychological origins related to the patient himself. Strenuous physical exercises have been frequently associated with the appearance of VCD     , and this is a serious problem for athletes committed to optimizing their physical performances. Psychological stress too can cause VCD, and if not timely detected might lead to prescribe ineffective and potentially harmful medications, instead of focusing the attention on the patient’s social environment which may be in the end the real cause of his psychological distress .
While the mortality of VCD is still unknown, morbidity appears to increase with the use of corticosteroids, which usually results in the occurrence of key pathologies like bone density loss and growth suppression in the pediatric population . Furthermore, VCD is much more frequent in women than men, with a female-to-male ratio of around three to one, as well as in people between 20 to 40 years of age, although it might appear in any age group . The incidence of VCD is also very high in persons affected by psychiatric conditions or with increased body mass index . It is very interesting to remember the epidemiological data coming from US, that underlines how 10% of the patients which refer to referral centers seek asthma evaluation. This indicates how frequently VCD is mistaken with asthma.
The vocal cords follow a particular pattern of movements during the respiratory cycle, characterized by a partial abduction during inhalation and a partial adduction during exhalation. It is a phasic pattern taking place in the larynx, which ensures the unimpeded movement of the air to and from the lungs through constantly regulated changes of the glottis chink size. Vocal cord dysfunction can occur during inspiration, expiration, or both.
The exact cause of this disorder is still unclear and many experts believe that it might be multifactorial. Anyways, two are the major hypotheses that the experts tend to support. The first one is the mediation of the vagus nerve, which might alter the laryngeal tone and lower the threshold necessary to produce vocal cord spasm, or even participate somehow to the prolonged vocal cord adduction. According to the second hypothesis, instead, the major cause of VCD is the irritation of vocal cords due to a number of organic causes, such as the previously mentioned gastroesophageal and laryngopharyngeal refluxes.
As the real causes of VCD are still unknown, no special preventive action can be indicated, apart from the adherence to therapies guidelines and measures to decrease anxiety and anxiety attacks. A significant part in the VCD prevention is played by the patient himself, who should be aware of the precipitating factors and do everything possible to avoid them.
In vocal cord dysfunction (VCD), also known as laryngeal dyskinesia, paradoxical vocal cord motion (PVCM), paradoxical vocal fold motion (PVFM), inspiratory adduction, Munchausen’s stridor, episodic paroxysmal laryngospasm, psychogenic stridor or functional stridor, the airflow obstruction takes place at the level of larynx   , especially during the inspiratory phase. VCD frequently mimics other conditions such as upper airway obstruction or asthma by presenting the same main symptoms, like wheezing, cough, and dyspnea  . However, some key differences can be used to distinguished the VCD from asthma like the localization of airflow obstruction, the characteristic poor response to beta-antagonists and inhaled corticosteroids  , or the absence of hypoxemia . The final diagnostic confirmation comes from laryngoscopy, which provides the physician with a clear view of vocal cords and glottis.
Vocal cord dysfunction (VCD) is an abnormal adduction (movement towards the middle of the body) of the vocal cords which causes airflow obstruction during respiration. VCD frequently mimics asthma by presenting the same main symptoms, like wheezing, cough, and shortness of breath. However, some key differences can be used to distinguished the two disorders, like the different modality of attack, which primarily consists in a difficulty in inhaling during VCD and a difficulty in exhaling during asthma. Since VCD co-occurs with asthma in the 40% of the cases , this might be a paramount difference to distinguish the two disorders.
Although the cause of VCD is still unclear, a number of factors have been associated with it, like gastroesophageal and laryngopharyngeal reflux, which provokes long-term irritations and damages, and the quality of the environment, which is full of new pollutants and toxic products. VCD might also have physical and psychological origins related to the patient himself, like strenuous physical exercise or psychological stress.
VCD has to be treated with a multidisciplinary team of specialists and the use of different treatments. With the help of specialists, an appropriate plan of treatment can be arranged, based on measures like breathing exercises, behavioral therapy, use of anti-anxiety or antidepressant drugs, and hypnotherapy. As the real causes of VCD are still unknown, no special preventive action can be indicated, apart from the adherence to therapies guidelines and measures to decrease anxiety and anxiety attacks.