Summary of Laryngitis
Transcript for Laryngitis
Content Reviewers:Rishi Desai, MD, MPH, Yifan Xiao, MD, Tanner Marshall, MS, Sam Gillespie, Antonella Melani, MD
With laryngitis, “laryng-” refers to the larynx and “-itis” refers to inflammation.
So, laryngitis is inflammation of the larynx, something that especially affects children.
It’s further classified into acute if it lasts less than three weeks, and chronic if it lasts more than three weeks.
The larynx is located in the upper portion of the neck, just below where the pharynx splits into the trachea and the esophagus.
The larynx is also called the voice box because it contains the vocal cords, which are two folds of mucous membrane that can open and close like curtains.
When they are closed, air pressure builds up below them, causing them to vibrate and produce sound when we speak.
Like the rest of the respiratory tract, the walls of the larynx are made up of mucosal epithelium.
The mucosal epithelium contains goblet cells, which produce mucus to trap small foreign particles as well as columnar cells, which have cilia, which are tiny little hair like projections that moves mucus up the respiratory tract so it can be coughed out.
Acute laryngitis is most common and it’s usually due to an upper respiratory tract infection, most often due to a virus.
Bacterial infections are another cause of acute laryngitis, and sometimes they can develop during or right after a viral infection - that’s called a superinfection.
These bacteria, and particularly Haemophilus influenzae, have a special preference for the superior portion of the larynx and the epiglottis, causing epiglottitis.
In acute laryngitis, the goblet cells to over secrete mucus leading to congestion of the airway, and immune cells like neutrophils and macrophages release chemicals that cause pain and swelling.
Swelling of the vocal cords changes the way they move - imagine two thin sheets flapping in the wind turning into two large pillows that barely move.
As a result, the vocal cords don’t move and vibrating smoothly, which causes dysphonia, or hoarse voice.
Chronic laryngitis is less common and it’s associated with allergies, or the result of chronic exposure to irritating agents, like cigarette smoke.
Reflux laryngitis is another cause of chronic laryngitis and develops in people with severe gastroesophageal reflux disease where acid from the stomach goes all the way up the esophagus into the pharynx.