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What is laryngitis ?

Created by Ian Mannarino.

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Video transcript

- Communication and the human voice is an amazing invention. It's an amazing thing. Communication has lead to discoveries that are so important in our civilization, from science to art to the creation of complex human expression through words. In fact, it has lead our society to advance more than any other animal species on this planet. So it can actually be very frustrating when you're unable to communicate, and that's what actually happens in laryngitis. Laryngitis is inflammation, itis, of the larynx. But what is the larynx? The larynx is also known as the voice box, and in this picture that I've drawn out over here, you can see a human head, and though there are other body parts really important in creating communication and creating sound, such as, for example, the tongue right here, the mouth, the lips, the jaw, but one of the most important is the larynx, which I am outlining right here. And like I said, it's also known as the voice box. Now let me take a quick step back to really acknowledge what we're really looking at here. I've sketched out a 2D representation of essentially a human body, if you sliced right down the middle. So you see, like I said, I point out other structures like the tongue, the jaw. Here's the nose. This is the nasal passage up here, and back here, this is the esophagus, where all the food goes, and over here is the windpipe. Right here, this little flap that's kind of hanging off, is the epiglottis, and that's important for when we swallow so we don't get food in the windpipe. This little flap bends over and protects the airway. To understand the larynx, looking at the top view is probably the best way to go. And again, up here is the epiglottis that I'm highlighting right up here. So this might be the view that you would get if you looked straight down onto the larynx, above the epiglottis. And, of course, in this top view here's the tongue. I have it right here, also over here. So in peering down at the larynx, at the voice box, we can see this complex structure of different soft tissues. This is all considered the larynx, all this soft tissue right here that I'm circling, but what's really responsible for pitch and different tone are the vocal cords, these little white stringy things. In order to create sound, a person will exhale. They'll breathe out air from their lungs, and this air will pass through the trachea right here and through this opening in the larynx. This is also known as the glottic opening. So, air passing through this little opening creates sound. And the way sound is actually produced is very similar to wind rushing through an open window, if it's cracked slightly open. When air goes through a very tight space, it creates sound. It's also similar to what you hear when releasing a balloon that's filled with air. Air will rush out of the balloon and create a sound. And also note if you pinch the sides of a balloon, right, the sound can become more high pitched, and that's because the opening for the air to rush air is narrowed. So, it makes sense that these vocal cords would actually have to come together and narrow to be able to create sound. And when air rushes through, these vocal cords vibrate back and forth, which can lead to different pitches and tones in the voice. One final analogy that I want to use is probably the most relevant for the vocal cords. That would be the analogy of a guitar. In fact, I would say that the vocal cords act most like a guitar than anything else. The strings towards the top of the guitar are looser and really big and bulky, and this creates a very low intonation, low sound, whereas the strings towards the bottom of the guitar are thinner. They have less mass to them, and they're also tighter, and this creates a very high-pitched sound. So this actually starts to make a lot of sense when you think about inflammation. When there's inflammation of the larynx, the vocal cords are also involved, and, of course, inflammation means swelling. Swelling adds mass to the vocal cords and also prevents them from vibrating as well and makes the vocal cords really floppy. So, people who have laryngitis have a very hoarse and raspy voice. So that's really the principle behind the larynx and laryngitis. Now there are two main types of laryngitis, and I break it down into acute laryngitis, meaning laryngitis that occurs suddenly, and chronic laryngitis, that is lasting for a longer period of time. Now, acute laryngitis can go away fairly quickly, within days, maybe a week or so, whereas chronic may be lasting a longer time, two weeks or longer, and the causes of these two are very similar. You really just want to think what could end up causing swelling of the larynx. For acute, there's viral causes, which is, in fact, the most common cause of acute laryngitis. So, as part of the treatment, antibiotics are usually not given, because antibiotics don't work against viral illnesses. Second most common is just from overuse, and this can be from just vocal strain from yelling or overuse. For example, if you go to a very loud place, and you're having to yell at everybody. And also of note, whispering can actually cause acute stress on the larynx as well. So patients with laryngitis are actually recommended to not whisper, because it puts more strain on the voice. And lastly and more rarely is bacteria, but like I said, generally viral illnesses cause laryngitis, and these can be any virus that causes the common cold. If it migrates down to where the larynx is, these viruses can cause infection to the larynx and laryngitis. Now, the chronic causes are usually due to some sort of chemical or overuse or some sort of irritant. So, irritants are the cause of chronic laryngitis, because viral and bacterial illnesses tend to resolve after a little bit of time, however, if a patient has chronic sinus issues, sinusitis caused by viruses or bacteria, this can also lead to chronic laryngitis. And chronic irritants include such things as smoke from fire or different fumes. Chronic exposure to secondhand smoke can cause laryngitis, and overuse and repeated strain of the voice. For example, singing or talking a lot, like I'm doing right now, and also reflux disease or vomiting can cause chronic laryngitis. So, avoiding irritants is the best way to avoid laryngitis and also maintaining proper hygiene to avoid any viral illnesses or potentially, and very rarely, bacterial illnesses as well.