Vocal cord dysfunction
Vocal cord dysfunction (VCD) is a disorder that occurs when the vocal cords move toward each other when a person breathes, narrowing the airway and causing wheezing and difficulty breathing. VCD is also called paradoxical vocal cord motion (PVCM).
Normally when an individual breathes in (inhales) or out (exhales) the vocal cords are drawn apart by the muscles of the larynx (voice box) to make a wider opening for air to move into or out of the lungs. In an individual with vocal cord dysfunction, instead of being drawn apart, the vocal cords move together, narrowing and partially blocking the airway. This is called adduction of the vocal cords. Adduction of the vocal cords happens most commonly during inhalation, although it can also happen during exhalation. As a result of the narrowed airways, the individual may cough , wheeze, feel short of breath, or make a high-pitched, harsh sound (called stridor ) with each breath.
VCD is often misdiagnosed as either asthma or exercise-induced bronchospasm. As a result, many individuals with VCD are treated with inhalers and steroids for asthma, which do not help control VCD and which have potentially harmful side effects.
The number of people with VCD in the general U.S. population is unknown. The disorder often occurs in conjunction with asthma and is frequently a missed diagnosis. Several small studies have found that about 40 percent of individuals who have VCD also have asthma and that about 10 to 15 percent of individuals whose asthma does not respond to aggressive treatment (refractory asthma) actually have VCD.
VCD has been found in individuals as young as three and as old as 82. However, in adults it most often occurs between the ages of 20 and 40. In children it appears most often about age 14 or 15. VCD is much more common in females than in males. In children under 18, about 85 percent of individuals diagnosed with VCD are girls. In children, the disorder has a strong association with competitive sports and family orientation toward high achievement. In adults it has a strong association with anxiety and stress. This association with stress is present, but less frequent in children.
Causes and symptoms
VCD was first recognized in 1842, when it was thought that hysteria, a common designation at that time for several psychological conditions, brought about spasm of the muscles of the larynx. By 1900, it was generally accepted that VCD was the physical expression of stress or other psychological conditions. It was not until the 1980s that physicians began to revisit the assumptions about the disorder and examine more closely its physical causes. As of 2004, the causes of VCD was not completely clear.
In the early 2000s, it is thought that the disorder may have multiple causes and that some of the triggers may be different in children and adults. VCD appears to be associated with the following:
- injury to the brain cortex
- brainstem compression (mainly in children)
- Arnold-Chiari syndrome (mainly in children)
- gastroesophageal reflux disease (GERD; in children and adults)
- chronic sinus infection/postnasal drip
- strenuous exercise (often in children)
- exposure to inhaled irritants (smoke, toxic chemicals; mainly in adults)
- psychological causes (most obvious in adults)
- nerve injury during congenital heart disease surgery or other chest surgeries
- failure to respond to asthma treatments
VCD usually comes on suddenly. Between attacks, the individual can breathe normally. The symptoms of a VCD attack are varied, but most strongly imitate those of asthma. Its similarity to asthma, along with the fact that some people with VCD actually also have asthma, complicates diagnosis. Common signs and symptoms include the following:
- coughing (about 75% of individuals)
- voice changes during an attack
- difficulty inhaling (most common)
- difficulty exhaling (less common; usually irritant-induced)
- panic, anxiety, fear of suffocating
- insufficient oxygen in the blood (hypoxia)
- chest tightness
- panting in short shallow breaths
- feeling like something is stuck in the throat
- skin turning blue
When to call the doctor
Immediate emergency medical assistance is essential whenever there are any signs of breathing difficulty.
Diagnosis of VCD is quite difficult. VCD can mimic the symptoms of severe asthma, allergic reactions ( anaphylaxis ), spasm of the larynx (laryngospasm), or a foreign object lodged in the throat. VCD is often a diagnosis of exclusion, which means that other possibilities are considered first, and when these are eliminated, VCD is considered. This may require a lot of testing.
The best way to determine if an individual has VCD is by doing a laryngoscopy. In a laryngoscopy, a slender, flexible tube containing a fiber optic camera is inserted through the nose and down the throat to the larynx. This examination allows the doctor to see the vocal cords and watch how and when they move.
Since between attacks the vocal cords appear to move normally, it is necessary to trigger an attack. Individuals cannot voluntarily produce symptoms of VCD, so they are usually exposed to an irritant or undergo an exercise stress test in order to bring on a VCD attack. The doctor then watches the vocal cords move. A classic finding is that the vocal cords move toward each other when the individual inhales, leaving a small triangular hole or chink at the back of the larynx. Individuals with asthma do not show this triangular chink.
Most people go through a series of other tests and often get other diagnoses, most commonly refractory (unresponsive) asthma, before they have a laryngoscopy and receive a definite diagnosis of VCD. Other tests that are frequently done to pinpoint or eliminate certain respiratory disorders include arterial blood gas values (to measure oxygen in the blood), pulmonary function tests (to measure lung capacity), with flow-volume loops (to measure the rate of air flow at different points in the breathing process). A methacholine provocation test, which stimulates a response in asthmatics, but not in persons with VCD, also helps narrow the diagnosis.
Treatment consists of two phases, immediate (acute) and long term. Acute care often occurs in a hospital emergency room. The most important aspect of acute care is to see that the individual is breathing and getting enough oxygen. Sometimes heliox therapy is given. Heliox is a mixture of 20 to 30 percent oxygen and 70 to 80 percent helium. Because this mixture is less dense and more oxygen-rich than regular air, it is easier to inhale. If the individual is still not getting enough oxygen, it may be necessary to perform a tracheotomy. In this operation, a tube is inserted in the larynx so that air can bypass the blockage.
Long-term therapy begins by stopping any treatments for other diagnoses such as asthma, and treating any underlying conditions, such as brainstem compression or GERD, affecting the disorder. Airborne irritants are removed from the individual's environment as much as possible. Speech therapy and teaching abdominal breathing techniques have been quite successful in preventing VCD attacks. If an individual does not respond adequately to speech therapy, psychotherapy is recommended, as in many people anxiety and stress are linked to VCD attacks. People can learn relaxation techniques and work through problems causing stress and anxiety. Occasionally anti-anxiety drugs are prescribed.
Arnold-Chiari syndrome —A congenital malformation of the base of the brain.
Asthma —A disease in which the air passages of the lungs become inflamed and narrowed, causing wheezing, coughing, and shortness of breath.
Exercise-induced bronchospasm —A sudden contraction in the lower airway that causes breathing problems and is brought about by heavy exercise.
Gastroesophageal reflux disease (GERD) —A disorder of the lower end of the esophagus in which the lower esophageal sphincter does not open and close normally. As a result the acidic contents of the stomach can flow backward into the esophagus and irritate the tissues.
Laryngoscope —An endoscope that is used to examine the interior of the larynx.
Stridor —A term used to describe noisy breathing in general and to refer specifically to a high-pitched crowing sound associated with croup, respiratory infection, and airway obstruction.
In an experimental procedure, botulinum toxin (Botox) may be injected into the larynx. The drug paralyzes the muscle, making it impossible for the vocal cords to move across the airway. This technique appears to be successful but may require repeated injections as the toxin wears off. Another experimental device is a facemask that provides resistance when the individual inhales but not during exhalation. The resistance forces the person to breathe in more slowly and reduces stridor.
Some individuals have found biofeedback very helpful in controlling or moderating VCD attacks. Others have benefited from relaxation and mind control techniques.
The long-term outcome for VCD is not known and probably varies among individuals depends on the underlying cause of the disorder. Only a handful of people with VCD have been followed for 10 or more years, and all of them continued to have symptoms of the disorder. However, speech therapy and psychotherapy are often successful in reducing the number of attacks.
Although the physical conditions that cause VCD cannot be prevented, individuals can be educated not to panic and to use certain breathing techniques when they begin to feel symptoms of VCD. In addition, airborne pollutants should be eliminated from the individual's environment. These steps can be somewhat successful in minimizing attacks.
Parents have obvious reason to be concerned when their child has sudden breathing problems. Many children with VDC make multiple trips to the emergency room before the condition is correctly diagnosed. Many medical professionals are only marginally familiar with VCD, because this problem is much less common than asthma. Parents may want to suggest additional testing for VCD if their child is being treated for asthma without success.
Leggit, Jeff. "Vocal Cord Dysfunction." American Family Physician 69 (March 1, 2004): 1045.
Perkins, Patrick J., and Michael J. Morris. "Vocal Cord Dysfunction Induced by Methacholine Challenge Testing." Chest 122 (December 2002): 1988–93.
Rundell, Kenneth W., and Barry A. Spiering. "Inspiratory Stridor in Elite Athletes." Chest 123 (February 2003): 468–74.
Truwit, Jonathon. "Pulmonary Disorders and Exercise." Clinics in Sports Medicine 22 (January 2003): 161–80.
National Jewish Medical and Research Center. 1400 Jackson Street, Denver, CO 80206–2671. Web site: http://www.njc.org/.
Buddiga, Praveen, and Michael O'Connell. "Vocal Cord Dysfunction." eMedicine Medical Library , October 27, 2003. Available online at http://www.emedicine.com/med/topic3563.htm (accessed December 3, 2004).
National Jewish Medical and Research Center. "Vocal Cord Dysfunction." Medfacts , July 15, 2004. Available online at http://www.nationaljewish.org/medfacts/vocal.html (accessed December 3, 2004).
Sidofsky, Carol. Can't Breathe? Suspect Vocal Cord Dysfunction. Available online at http://www.cantbreathesuspectvcd.com (accessed December 3, 2004).
Tish Davidson, A.M.