Laryngitis

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Introduction0:00–0:21

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.

Physiology0:21–1:06

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 laryngitis1:06–2:27

Acute laryngitis is most common and it’s usually due to an upper respiratory tract infection, most often due to a virus.
These viruses are the same ones that cause the common cold like rhinovirus, coronavirus, influenza virus, respiratory syncytial virus- or RSV for short, and parainfluenza 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.
Common bacterial causes include Group A streptococcus, Streptococcus pneumoniae, or Haemophilus influenzae. 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.

Chronic laryngitis2:27–3:22

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.
From there, the acid can contact and irritate the larynx. Finally, there’s overuse of the voice, like yelling or a really prolonged karaoke session involving the Beatles, that could lead to both acute and chronic laryngitis.
In chronic laryngitis the normal columnar cells undergo dysplasia, which is when they transform into squamous epithelium to adapt to the chronic irritation.
This dysplasia increases the chance that these cells might eventually develop into laryngeal cancer. The main symptoms of laryngitis include hoarse voice or dysphonia, cough, and in severe cases it can lead to difficulty swallowing or dysphagia, because the swollen larynx may compress the esophagus.

Symptoms3:22–3:51

Some children have shortness of breath or dyspnea, since they have smaller airways. So laryngitis comes down to the three D’s: dysphonia, dysphagia, and dyspnea.

Diagnosis3:51–4:13

Diagnosis of acute laryngitis is mainly based on symptoms. For chronic laryngitis, though, laryngoscopy can be useful.
That’s when a long tube containing a camera is inserted into the mouth to directly see the larynx, and to take a biopsy of the tissue if needed.
The main purpose is to ensure that there’s no sign of a laryngeal cancer. Generally speaking, for acute laryngitis, the treatment is resting the vocal cords, as well as getting fluids, and pain medications.

Treatment4:13–4:39

For bacterial infections antibiotics are helpful. For chronic laryngitis, it’s important to treat the underlying issue, for example, using allergy medication, avoiding irritating agents, and using gastroesophageal reflux medications.

Review4:39–6:12

Alright, as a quick recap, laryngitis is inflammation of the vocal cords and it causes dysphonia, dysphagia, and dyspnea.
Acute laryngitis usually lasts for less than three weeks, and usually resolves on its own, although antibiotics are helpful for bacterial laryngitis.
Chronic laryngitis lasts for more than three weeks, and is usually caused by allergies or exposure to irritating agents, or gastroesophageal reflux.