Vocal cord dysfunction (VCD) and exercise-induced laryngeal obstruction (EILO): Overview

What are vocal cord dysfunction and exercise-induced laryngeal obstruction?

Vocal cord dysfunction (VCD) is a condition where the vocal cords or nearby tissues in the voice box (larynx) close instead of opening during inhalation (breathing in). This can cause symptoms such as shortness of breath or breathlessness, noisy breathing (often heard when breathing in) and a feeling of tightness in the throat or upper chest. These symptoms happen because less air reaches the lungs when the vocal cords narrow or close.

VCD is also known by other names, including:

• inducible laryngeal obstruction (ILO)
• paradoxical vocal fold motion/dysfunction (PVFM/D)

When these breathing symptoms mainly happen during physical activity or sports, it is called exercise-induced laryngeal obstruction (EILO). Although there are no medications or puffers that treat VCD or EILO, the good news is that most people improve significantly with the right breathing techniques, guidance and support. With practice and the right tools, your child or teen can learn to manage their symptoms and get back to doing the activities they enjoy.

What happens in the voice box during VCD and EILO?

Vocal cords are two muscular folds inside your voice box (also called the larynx). When you breathe in, your vocal cords open to allow air to enter your lungs. To speak, your vocal cords come together and vibrate against each other to create sound as the air passes out from your lungs. In people with VCD, the vocal cords close or come close together when they breathe in, making it difficult to take a full breath. They might also make a sound, called stridor, when trying to breathe in.

For some people, other parts of the voice box above the cords (called the supraglottic structures) might close during breathing, leading to similar symptoms. These supraglottic structures seem to be more affected in people who have EILO than in people with VCD.

Common signs and symptoms of VCD and EILO

People with VCD often describe episodes or "attacks" where it suddenly becomes hard to breathe. This occurs when your child is awake and generally does not occur during sleep.

In EILO, symptoms can become intense enough that a person needs to slow down or stop the activity altogether.

If your child has VCD or EILO, they may experience the following signs and symptoms:

• Shortness of breath
• Trouble getting air in or out
• Tightness in the throat or chest
• Noisy breathing when breathing in (called stridor)
• Frequent coughing or throat clearing
• Feeling like they are choking
• Changes in voice (less common)

VCD and EILO are often mistaken for asthma due to their overlapping symptoms, but they are treated differently. Some people can have both asthma and VCD or EILO. In fact, research suggests that children and adults who have asthma that is hard to control may be more likely to also have VCD or EILO. If your child’s asthma symptoms are not improving with usual treatment (such as puffers), it is worth talking to your child’s health-care provider about whether VCD or EILO might also be playing a role.

What causes VCD and EILO?

Health-care providers do not fully understand why VCD and EILO happen. It is suspected that these conditions are caused by a mix of different factors, which may vary from person to person. One possible cause is that the nerves in the voice box become extra sensitive. When the nerves are exposed to certain triggers—such as exercise, strong smells or stress—they may react in a way that causes the vocal cords or other tissues to close instead of staying open. Experts believe this is due to an oversensitive reflex in the voice box. This reflex is normally there to help protect your lungs and make sound, but in VCD, it may become too active.

In EILO, the problem may have more to do with the size and structure of the voice box and pressure changes that happen with heavy breathing that occurs during intense exercise. These pressure changes may cause parts of the voice box to collapse or close, leading to symptoms of EILO.

How common are VCD and EILO?

It is not known exactly how many people around the world have VCD as there has not been enough research yet to give a clear answer. More is known about EILO—it is fairly common, especially in teenagers, and seems to happen more frequently in females. Studies suggest that 5 per cent to 8 per cent of teens and young adults may experience EILO. EILO may be even more common in elite athletes with rates as high as 35 per cent.

What are common VCD triggers?

People with VCD have episodes or "attacks" where it suddenly becomes hard to breathe. Episodes can be triggered by the following:

• Acid reflux or heartburn (GERD)
• Asthma, colds or other respiratory infections
• Strong scents and smells
• Dust, smoke, pollution or fumes
• Stress, anxiety or strong emotions
• Eating or talking
• Exercise and physical activity (in people with EILO)

Exercise is a common trigger in older children and teens and can lead to challenges with participation and performance.

Sometimes, there is no clear trigger at all.

How are VCD and EILO diagnosed?

VCD and EILO can be difficult to diagnose because their symptoms often look very similar to asthma, especially during exercise. Sometimes, children may have both asthma and VCD/EILO at the same time. Understanding the differences between asthma and VCD/EILO is an important step in getting the right diagnosis and treatment. Check out the table below for a comparison of the two conditions.

Differentiating VCD/EILO from asthma

While the table above outlines typical or “classic” symptoms of the two conditions, symptoms can often overlap or be difficult for your child to explain. This is why their health-care provider may recommend seeing a specialist and undergoing specific testing for both VCD/EILO and asthma.

Diagnosing VCD or EILO usually involves a combination of a detailed discussion of your child’s symptoms, a physical exam and diagnostic tests. Because VCD and EILO can look like other conditions—such as asthma, other lung problems or even heart issues—your child’s health-care provider may recommend testing to rule those out and help make the right diagnosis. However, not all these tests need to be performed in everyone. Your child’s health-care provider may also recommend recording a video of an episode. In some cases, video can be very helpful in identifying the characteristic features of VCD/EILO such as stridor (high-pitched noise during inhalation). To learn about the types of diagnostic tests your child might have, please see Vocal cord dysfunction (VCD) and exercise-induced laryngeal obstruction (EILO): Diagnosis.

How are VCD and EILO managed?

There is no quick fix or medication that treats VCD or EILO, but most people improve with individualized treatment plans and support from a team of experienced health-care professionals. Management generally includes learning about the condition, using rescue breathing techniques and respiratory retraining. To learn more, please see, Vocal cord dysfunction (VCD) and exercise-induced laryngeal obstruction (EILO): Treatment.

When to seek immediate medical attention

While VCD and EILO attacks can feel scary, they are usually not dangerous and tend to go away quickly on their own or with breathing techniques. However, you should seek immediate medical attention if your child:

• has severe difficulty breathing that is not improving
• is turning blue or pale around the lips or face
• has trouble speaking or swallowing
• has significant chest pain that is not going away

Given that VCD and EILO can look like asthma attacks or even anaphylaxis, it is important to be cautious. If you are uncertain, or otherwise worried, do not hesitate to go to your nearest emergency department or call 911.

Resources

American Thoracic Society

What are vocal cord dysfunction (VCD) and inspiratory laryngeal obstruction (ILO)?

Exercise-induced laryngeal obstruction

University of Calgary: Dysfunctional breathing (DB), exercise-induced laryngeal obstruction (EILO), inducible laryngeal obstruction (ILO), paradoxical vocal fold motion (PVFM) and vocal cord dysfunction (VCD) resources

National Jewish Health: Vocal cord dysfunction (VCD)

References

Christensen, P. M., Thomsen, S. F., Rasmussen, N., & Backer, V. (2011). Exercise-induced laryngeal obstructions: Prevalence and symptoms in the general public. European Archives of Oto-Rhino-Laryngology, 268(9), 1313–1319. https://doi.org/10.1007/s00405-011-1612-0

Johansson, H., Norlander, K., Berglund, L., Janson, C., Malinovschi, A., Nordvall, L., Nordang, L., & Emtner, M. (2015). Prevalence of exercise-induced bronchoconstriction and exercise-induced laryngeal obstruction in a general adolescent population. Thorax, 70(1), 57–63. https://doi.org/10.1136/thoraxjnl-2014-205738

Nielsen, E. W., Hull, J. H., & Backer, V. (2013). High prevalence of exercise-induced laryngeal obstruction in athletes. Medicine and science in sports and exercise, 45(11), 2030–2035. https://doi.org/10.1249/MSS.0b013e318298b19a