Vocal Cord Dysfunction (VCD) is a breathing disorder where the vocal cords, or vocal folds, close together when they should be opening to allow air into the lungs. This condition is also frequently referred to as Paradoxical Vocal Fold Movement (PVFM) because the movement is contrary to the normal breathing process. The closure temporarily restricts the airway, which leads to sudden difficulty breathing. VCD is an episodic condition that can sometimes be confused with other respiratory ailments.
The Mechanism of Vocal Cord Dysfunction
The vocal cords, two muscular folds located within the larynx, serve three primary functions: speech, airway protection, and regulation of airflow during breathing. In a person without VCD, the vocal cords automatically move apart, or abduct, widely during both inhalation and exhalation to create a clear passage for air to travel to and from the lungs. This normal action ensures unobstructed respiration.
During an episode of VCD, this coordination is lost, and the vocal cords inappropriately move toward each other, or adduct, primarily during inhalation. This paradoxical movement creates a functional obstruction in the upper airway, effectively forming a bottleneck that severely limits the amount of air that can pass into the lungs. The mechanism is functional, meaning it involves an error in muscle coordination or a hypersensitive reflex, rather than a fixed structural problem. The resulting narrow opening causes the characteristic symptoms.
Recognizing Symptoms and Common Triggers
The obstruction created by the closing vocal cords leads to a distinct set of symptoms, the most prominent of which is inspiratory stridor, a high-pitched, noisy sound heard when breathing in. Patients often describe a sensation of tightness or closing in the throat or neck, which can feel like suffocation. Because the air is restricted from entering the lungs, people with VCD experience significant difficulty getting air in, which is the opposite of the typical breathing struggle associated with asthma.
Episodes are often intermittent and can be triggered by a wide variety of factors that irritate the highly sensitive laryngeal area. Physical exertion, such as intense exercise, is a common precipitator of VCD symptoms. Inhaled irritants, including strong odors like perfumes, fumes, cleaning chemicals, or smoke, can provoke an episode. Furthermore, internal factors such as Laryngopharyngeal Reflux (LPR), where stomach acid travels up to the throat, and emotional stress or anxiety are frequently reported triggers for the condition.
Differentiating VCD from Asthma and Other Conditions
VCD is frequently misdiagnosed as bronchial asthma due to the overlapping symptoms of wheezing, coughing, and shortness of breath. The fundamental distinction lies in the location of the airway restriction; VCD affects the upper airway at the level of the larynx, while asthma involves the lower airways, specifically the bronchial tubes within the lungs. This difference in location dictates which phase of breathing is most affected.
Patients with VCD report that the greatest difficulty is with inhalation, whereas those with asthma usually struggle more during exhalation as the lower airways narrow. The sound associated with VCD is stridor, which originates in the throat, while the sound in asthma is a wheeze that comes from the chest. A critical differentiating factor is the response to treatment; standard asthma inhalers, which open the lower airways, are ineffective in relieving the symptoms of VCD. VCD episodes may also be mistaken for other acute conditions like panic attacks or anaphylaxis.
Diagnosis and Essential Management Strategies
Confirming a diagnosis of VCD requires specialized testing, particularly because symptoms are often absent during a routine examination. The gold standard for diagnosis is dynamic laryngoscopy, a procedure where a physician visualizes the vocal cords using a thin, flexible scope, ideally during a symptomatic episode. This allows for direct observation of the paradoxical closure of the vocal folds upon inhalation.
Pulmonary Function Tests (PFTs) are also valuable, as VCD can produce a specific pattern on the flow-volume loop, characterized by a flattened inspiratory curve, indicating an obstruction in the upper airway. Once a diagnosis is established, the management strategy is specialized speech therapy, often called respiratory retraining therapy. This non-pharmacological approach teaches patients specific breathing techniques to consciously override the involuntary closure of the vocal cords and relax the throat muscles during an episode. Managing underlying triggers, such as treating LPR with diet or medication, or addressing anxiety with behavioral therapies, is also an important part of the long-term control of VCD.