Vocal Cord Dysfunction
CC: Persistent Cough
A common complaint that I see in primary care is cough. This can be acute, subacute, or chronic as we have discussed in our past article on the evaluation of chronic cough. Today we are going to discuss a single etiology for patients that have a persistent cough a little more in depth. This cause is vocal cord dysfunction (VCD).
What is VCD?
VCD is a condition where there is inappropriate vocal cord movement, which leads to partial airway obstruction giving the patient a feeling of respiratory distress.
During normal respiration; on inspiration, the vocal cords move away from the midline; whereas, on expiration, the vocal cords move slightly towards the midline. These movements cause various levels of airway obstruction.
Synonyms of VCD
Vocal cord dysfunction has been and can be referred to with many different titles in literature. These names include paradoxical vocal fold motion, factitious asthma, or paradoxical vocal cord dysfunction.
How Does Vocal Cord Dysfunction Present?
Vocal cord dysfunction occurs more commonly in females, as opposed to males, and often will occur between ages 20 to 40 years old. However, there have been cases where the diagnosis has been made in children as young as 8 years old.
Patients will often present with complaints of:
- Distressed breathing
- Throat scratchiness or tightness
- A choking sensation.
Most patients’ symptoms will be intermittent and relatively mild; however, some may have persistent and significant impairments associated with their symptoms.
Misdiagnosis - Stridor vs. Wheezing
A patient’s stridor in VCD can easily be mistaken for wheezing leading to a misdiagnosis of asthma. In one study, around 59 percent of patients with VCD had been initially diagnosed with asthma.1
Subtypes of VCD
There are 2 subtypes of VCD that can lead to aphonia, respiratory distress, hoarseness, and strained vocalization. The subtypes are:
- Spasmodic dysphonia
What Should Our Differential Diagnosis Include?
Clinicians tend to get tunnel vision with VCD and it often leads them towards a diagnosis of asthma; this is because of the common complaints of wheezing and labored breathing, often resulting in misdiagnosis. Interestingly, there are a vast majority of patients with VCD that will also have comorbid asthma, making the diagnosis much more difficult.1
Some additional diagnoses that may come to mind in a patient that presents with these symptoms include:
- Vocal cord polyps
- Foreign body obstruction
A focused history and physical examination can help differentiate between the two diagnoses.
However, further testing with pulmonary function testing (PFT) or laryngoscopy is typically needed to make the appropriate diagnosis.
What are the Triggers for VCD?
Vocal cord dysfunction can be associated with a myriad of inciting factors, but there is no clear pathophysiology as to why they occur at this point.
Exercise has been seen to be a common cause of VCD. As you can imagine, exercise-induced vocal cord dysfunction will be commonly diagnosed as exercise-induced asthma. This should come to the forefront of a clinician’s mind if a patient has a diagnosis of exercise-induced asthma, but is not responding to bronchodilator therapies.
Data has shown a link between VCD and several psychologic conditions, including but not limited to; anxiety, depression, PTSD, and anxiety attacks. Anxiety disorders are especially common in teenage patients who present with vocal cord dysfunction. However, it is important to note that anxiety may be the result of the respiratory symptoms, rather than the cause.
Allergens and Irritants
Exposure to occupational and environmental allergens and irritants has been seen to cause respiratory symptoms leading to VCD. Common irritants include:
- Soldering fumes
- Cleaning chemicals
- And more
In fact, Studies have revealed that there is a definite temporal relationship between exposure to irritants and the onset of vocal cord dysfunctions symptoms.1
Postnasal drip (PND) that is caused by rhinosinusitis has been found to lead to airway hyperresponsiveness. Interestingly, there are also a large number of cases of rhinosinusitis in patients diagnosed with VCD. Furthermore, studies show that successful treatment of rhinosinusitis positively correlates with the resolution of symptoms of vocal cord dysfunction.
GERD may be another trigger to VCD. Studies show that there is a high prevalence of GERD in patients who suffer from VCD. However, the treatment of GERD was not as effective in resolving VCD symptoms.
Some medications such as phenothiazines have been seen to trigger intermittent episodes of vocal cord dysfunction. This is believed to be due to a focal dystonic reaction and is often associated with extrapyramidal side effects.
Diagnostic Approach to Vocal Cord Dysfunction
The most important diagnostic tests for VCD include, pulmonary function tests (PFT) and flexible laryngoscopy. PFTs with a flow-volume loop are the most commonly used test to confirm VCD. During the flow-volume loop, it is routine to find the expiratory loop to be normal, and the inspiratory loop to be flatter in shape.
This is consistent with an extrathoracic upper airway obstruction. This pattern is common when patients are symptomatic at the time of testing. However, even when patients are asymptomatic, some patients that have VCD will have inspiratory loop flattening.
Exercise flow-volume loops can be completed as well and can be particularly useful for diagnosis in those patients who are thought to have exercise-induced vocal cord dysfunction.
PFTs are particularly useful in differentiating VCD vs. asthma. This is because bronchospasms, characteristics of asthma, will show impairment of the expiratory loop. In patients where their PFTs are unclear whether they have asthma or VCD, the next step would be to complete a methacholine challenge testing. A methacholine challenge is often used in the diagnosis of asthma.
Flexible laryngoscopy is considered the gold standard for the diagnosis of VCD. Direct visualization of irregular movement of the vocal cords toward the midline during inhalation or exhalation confirms the diagnosis. Those patients who are symptomatic will almost certainly display abnormal movement, and those asymptomatic patients will show abnormal movements over half of the time as well.1
The initial treatment of VCD includes:
- Lifestyle intervention
- Breathing instructions can aid in the resolution of an acute symptomatic episode.
- Studies have shown that having a patient breath short and rapid breaths (panting) can result in a quick resolution of symptoms.
Additional breathing exercises such as:
- Diaphragmatic breathing
- Pursed-lip breathing
- Breathing through the nose
- Exhaling with a hissing sound
- Breathing through a straw can be helpful as well.
Severe Respiratory Distress
Administration of helium and oxygen (Heliox) has been shown to reduce airway resistance and may provide quick improvement of symptoms in patients.
Long term management of VCD includes eliminating precipitating factors. Treatment of underlying conditions, such as:
- Medication changes
- Airborne irritant exposure
Chronic VCD Treatment
Additionally, speech therapy is the mainstay of long-term treatment of chronic vocal cord dysfunction. This therapy teaches a variety of techniques, including relaxed throat breathing, which has shown to improve symptoms and reduce recurrent symptoms.
Treatment of exercise-induced VCD
Anticholinergics also can aid in patients who have exercise-induced VCD. One trial found that patients who were pretreated with ipratropium, showed improvement of symptoms during and after exercise.
Severe, Resistant VCD
In severe cases of vocal cord dysfunction that is resistant to all other treatments and therapy, long-term tracheostomy has been reported.
- Am Fam Physician. Vocal Cord Dysfunction. 2010;81(2):156-159, 160. Copyright © 2010 American Academy of Family Physicians.
- Paradoxical Vocal Cord Motion. Accessed: April 15, 2019.
- UpToDate. Exercise-Induced Laryngeal Obstruction. Accessed: April 15, 2019.
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