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What is inducible laryngeal obstruction? — Inducible laryngeal obstruction, or ILO, is a condition that causes wheezing, trouble breathing, and coughing.
Normally, when you breathe in and out, your vocal cords open like curtains to let air into your lungs. In people with ILO, the vocal cords sometimes stay shut or open only a little (figure 1). This can happen during exercise or after something irritates the throat. This makes it hard to breathe and causes other symptoms.
Another term for ILO is "vocal cord dysfunction."
What causes ILO? — The vocal cord problem that causes the symptoms of ILO doesn't happen all the time. The word "inducible" means it happens in response to something else. Things that can cause ILO are called "triggers." Possible triggers include:
●Exercise
●Having a breathing tube removed (for example, after surgery)
●Breathing in irritating fumes or chemicals
●Acid reflux
●Postnasal drip (when mucus from the nose drips down along the back of the throat)
●Stress or anxiety
Sometimes there is no obvious trigger for ILO, and it just happens.
What are the symptoms of ILO? — During an episode of ILO, the main symptoms include:
●Trouble breathing
●Wheezing or making a whistling sound when you breathe
●Throat tightness
●A feeling that you are choking
●Trouble speaking
●Cough
When symptoms happen only with exercise, doctors call this "exercise-induced laryngeal obstruction" or EILO. People with this problem sometimes have other symptoms, too. They might feel like there is a lump in the throat, or have trouble swallowing, or a hoarse voice. Symptoms go away within seconds or a few minutes after the person stops exercising. Some people have episodes of EILO only when exercising very hard. Other people might have episodes when they exercise less intensely.
Should I see a doctor or nurse? — Yes. If you have symptoms of ILO, see your doctor or nurse.
Is there a test for ILO? — Yes, there is a test. Asthma and ILO cause many of the same symptoms, so if your doctor suspects you have ILO, they will first do breathing tests to check you for asthma.
If the doctor still suspects ILO, they can put a small tube with a camera on the end through your nose and into your throat. This tube, called a laryngoscope, allows the doctor to look at your vocal cords and see if they move normally. It's possible you'll need other tests to make sure something else is not going on, but this is the main test for ILO.
If your doctor thinks your symptoms are related to exercise, they will look at your vocal cords with the laryngoscope while you are exercising. This usually involves putting the tube into your throat, attaching the outer part to a headpiece so it stays in place, and connecting it to a video screen. Then you ride an exercise bike, or run on a treadmill, while the doctor monitors you.
How is ILO treated? — An episode of ILO usually stops on its own. While it is going on, doctors might do 1 or more of the following:
●Ask you to take fast, shallow breaths (panting) – This can sometimes make the vocal cords open up. They might also ask you to focus on breathing through your nose.
●Put a device over your nose that gently blows in air – This is called "continuous positive airway pressure," or "CPAP."
●Give you oxygen to breathe
●Treat your asthma, if you have it – Some people with ILO also have asthma. If you have asthma, you will get medicine to treat it.
If you have ILO caused by exercise, long-term treatment involves working with a speech and language pathologist, or "SLP." An SLP can teach you special ways to breathe during exercise so that your vocal cords don't close up.
Can ILO be prevented? — Yes, with the right treatment, ILO can be prevented. Working with a speech and language pathologist can help with this. They can teach you ways to change the way you speak and breathe. They can also teach you how to relax when you are having problems, so that you can start breathing normally again as quickly as possible.
Asthma medicines do not help ILO. But if you have both asthma and ILO, you will need medicine for your asthma.
Your doctor or nurse might also prescribe medicine for acid reflux in case reflux is bothering your vocal cords. Postnasal drip from allergies or sinus problems can also irritate the vocal cords, so you might need treatment for these.
If your ILO is related to stress or anxiety, dealing with these problems can help. Your doctor or nurse can help you find ways to do this. It might help to talk to a counselor or therapist.