Vocal cord dysfunction
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|Vocal Cord Dysfunction|
|Classification and external resources|
Vocal cord dysfunction (VCD) is a pathology affecting the vocal folds, commonly referred to as the vocal cords. VCD is characterized by full or partial vocal fold closure that usually occurs for short periods during inhalation but can also occur during exhalation. Alternate terms for VCD include paradoxical vocal fold motion (PVFM) and paradoxical vocal cord movement (PVCM).
Symptoms can include shortness of breath (dyspnea), wheezing, coughing, tightness in the throat, skin discoloration due to oxygen deprivation (cyanosis), noise during inhalation (stridor), and in severe cases, loss of consciousness. 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.
"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.
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 incidences 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.
Vocal cord dysfunction is often diagnosed only after other potential conditions have been excluded. Those suffering from it will also likely have failed to respond to medication and other treatments before VCD is considered. This may mean several hospitalizations that are unresponsive to conventional treatments, such as asthma medication.
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.
The first step to treat VCD is to stop unnecessary treatment. The use of steroids is not effective in VCD unless needed to treat underlying asthma and should be discontinued to avoid the morbidity associated with their use and to prevent severe long-term consequences, including growth retardation in children. Customary treatments are often multidisciplinary and include, in addition to breathing exercises by speech-language pathologists, psychotherapy, behavioral therapy, use of anti-anxiety and anti-depressant medications, and hypnotherapy. There is no uniform approach and management should be individualized. The information from randomized, blinded studies is limited.
Acute treatments can include heliox, intermittent positive pressure ventilation and continuous positive airway pressure. Severe cases may require a tracheotomy for temporary relief. Botox injections can also be made into the vocal folds.
If there is an underlying condition to which vocal cord dysfunction is secondary, it is important to treat the primary condition which alone can help with control.
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