Nasal polyps

Definitions & Key takeaways

Nasal polyps are benign growths that develop in the lining of the nose or sinuses. They result from hyperplasia of the epithelial cells that line the respiratory region - especially in the maxillary and ethmoidal sinuses.

Nasal polyps are typically soft, pale, and teardrop-shaped, and can range in size from a few millimeters to several centimeters. They can obstruct airflow through the nasal cavity and prevent sinus mucus from draining normally. Their treatment involves steroids, or sometimes surgery, but have a high likelihood of returning.

Chapters:

Watch video only

Introduction0:00–0:12

A nasal polyp is a clump of epithelial cells that forms a small bump or overgrowth of tissue along the lining the nasal cavity, the inside of the nose.
The nasal cavity is made up of three regions. The first, is the nasal vestibule which is the area just inside the nostrils.

Physiology0:12–1:18

Beyond that, is the respiratory region which delivers air to the sinuses and lungs, and above it is the olfactory region, which is involved in smelling.
Lining the respiratory region are epithelial cells that create mucus to moisten the air and trap pathogens. There are also air-filled spaces within the skull that are on either side of the the nose called paranasal sinuses which are lined by the same layer of epithelial cells as the respiratory region.
The paranasal sinuses are named for the bones that house the sinus: the sphenoid, located next to the eyes; the ethmoid, between the eyes; the frontal, above the eyes behind the forehead; and the maxillary, behind the cheeks and below the eyes.
Each of the sinuses normally produce mucus, which drain into the respiratory region. Holes at the back of the respiratory region, called choanae act like funnels to direct the mucus into the throat to be swallowed.

Pathology1:18–2:04

Nasal polyps develop when epithelial cells that line the respiratory region simply overgrow - a process called hyperplasia.
Most of the time, one or more nasal polyps forms in the maxillary or ethmoid sinus. Nasal polyps can get large - the size of a pea, but they are usually non-cancerous, meaning they don’t break through the basement membrane of the epithelium.
Unfortunately, they often obstruct air flow as well as mucus drainage which allows pathogens to linger in the sinuses and cause infections.
Recurrent infections causes mucosal swelling as immune cells infiltrate the tissue and create an inflammatory response. The swelling makes airway obstruction and mucus drainage even worse.

Causes2:04–2:28

The reason that the epithelial cells start to grow into a polyp isn’t entirely clear but they are associated with seasonal allergies, having frequent asthma exacerbations, and chronic sinusitis.
There are some genetic factors that seem related as well, for example, individuals with cystic fibrosis and primary ciliary dyskinesia both have a high risk of developing nasal polyps.

Symptoms2:28–3:07

The symptoms of nasal polyps are usually related to blocked mucus drainage and obstructed air flow. As the polyps grow, they occlude the nearby choanae and block sinus mucus drainage.
This can leave the sinuses full of secretions that get infected - causing bouts of fevers and headaches when that develops.
Obstructed air flow can prevent air from reaching the olfactory region and decrease the sense of smell. It can also cause snoring and sleep apnea, and in young infants it can cause reduced levels of oxygenation, called hypoxia, which gives a bluish tinge to their skin color.

Diagnosis3:07–3:22

Nasal polyps are diagnosed visually with nasal endoscopy or by medical imaging with a CT. Diagnosis is often made after clinical symptoms become problematic, but changes to the respiratory mucosa can be detected even in their absence.

Treatment3:22–3:59

The treatment for polyps is to shrink them using steroids, usually in the form of a nasal spray. The steroids act to decrease the inflammation and swelling from the polyp.
But some polyps are unresponsive to steroids. This tends to happen when there are high levels of eosinophils, a specialized type of immune cell.
In these cases, endoscopic sinus surgery may be needed to cut them out. Unfortunately, because the underlying causes for polyps are often chronic conditions like allergies and asthma, polyps often return, so repeat treatments are typically needed.
So, a quick recap: Nasal polyps form as a result of hyperplasia of the epithelial cells that line the respiratory region - especially in the maxillary and ethmoidal sinuses.

Review3:59–5:10

Their growth obstructs air flow through the nasal cavity and prevents sinus mucus from draining normally. They are treated with steroids, or sometimes surgery, but have a high likelihood of returning.
Thanks for watching, you can help support us by donating on patreon, or subscribing to our channel, or telling your friends about us on social media.