What is Empty Nose Syndrome? Causes and mechanism

Understanding ENS

Empty Nose Syndrome is caused by surgery on the turbinates. The nasal cavity ends up wide open. The consequences are a loss of airflow sensation, nasal dryness, sleep problems and many other symptoms.

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01Anatomy 02The surgery 03The mechanism

Front cross-section of a healthy nasal cavity

Septum: The wall that splits the nose into two passages.
Inferior turbinate: The largest turbinate. It warms and humidifies most of the air. It is the one most often reduced in surgery.
Middle turbinate: It guides the airflow and protects the openings of the sinuses. Cutting it can also lead to ENS.
Sinuses: Air spaces around the nose: ethmoid between the eyes, maxillary in the cheekbones.
Mucosa: The tissue that covers everything. It holds the cold receptors, the mucus glands and the blood vessels.

Healthy nasal cavity — **Healthy**The turbinates warm and humidify the air, and give the sensation of airflow.

**Partial inferior turbinectomy**A wider passage and less mucosa.

**Total inferior turbinectomy**The turbinate is almost gone: the airway is wide open.

More empty space

Cross-sectional area
Air speed and wall shear stress
Evaporation of the mucus
Cooling of the mucosa
Activation of the TRPM8 receptors
Airflow sensation, then respiratory drive

Less mucosa

Number of TRPM8 receptors
Mucus production
Blood vessels, which keep the mucosa warm
Nasal cycle: the turbinates can't swell or shrink to adapt
Shortness of breath, central sleep apnea

Mechanism of Empty Nose Syndrome

The full explanation

Empty Nose Syndrome can be caused by a partial or a complete cut of the inferior or middle turbinates. It can even be caused by a burn of the mucosa. The cut causes a loss of volume, that's to say an increase in emptiness and a reduction in the mucosa surface. The burn affects negatively the health of the mucosa. All of this has many effects:

The increase in emptiness causes:

A modification in the distribution of the airflow, most of the airflow is redirected in the middle meatus in case of an inferior turbinectomy.¹
An increase in the cross-sectional area which reduces the velocity of the airflow and affects negatively the Wall Shear Stress. Less WSS means less evaporation of the mucus due to the airflow passage which leads to less cooling effect of the mucosa. Indeed the change of the mucus from the liquid state to the gaseous state leads to energy consumption which cools the mucosa. And it is this cooling that detects the TRPM8 receptors and gives us the feeling of the airflow.² The increase in the cross-sectional area also reduces nasal resistance.

The reduction in the mucosa surface causes:

A reduction in the numbers of TRPM8 receptors simply because the receptors are in the mucosa and the fewer mucosa there are, the fewer receptors there are.
A reduction of the production of mucus because it is the same thing, the glands that produce mucus are found in the mucosa.³
A reduction in the number of blood vessels which can decrease the temperature of the mucosa. Simply because the mucosa is kept at the right temperature thanks to the blood flow.

The nasal cycle

The cut of turbinates disturbs the nasal cycle because a large part of the turbinates has disappeared. The nasal cycle is the phenomenon that consists of vasodilation of the turbinates on one side and then the other over a cycle of a few hours. However, it seems that the utility of the nasal cycle is still unknown.⁴ But the phenomenon of vasodilatation/vasoconstriction has another very important role which is to adapt the cross-sectional area according to physical activity. Indeed during physical activity the airflow increases, in response to this, the turbinates decrease in volume via the phenomenon of vasoconstriction.⁵

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Could it be ENS?

The ENS6Q is a validated 6-question tool that ENT doctors use to help recognise Empty Nose Syndrome. Not a diagnosis, but a good first step.

Take the ENS6Q test

Frequently asked questions

Is Empty Nose Syndrome a real condition?

Yes. It has been described in the medical literature since the 1990s, and research teams study its mechanisms, its diagnosis and its treatments. The ENS6Q above comes from this research.

Which surgeries can cause ENS?

Mainly surgeries that remove or burn turbinate tissue: partial or total turbinectomy of the inferior or middle turbinates, and procedures that burn the mucosa.

How is ENS diagnosed?

An ENT looks at your surgical history, examines the nose and reviews a CT scan. Questionnaires like the ENS6Q and a cotton test can help. Find an ENT who knows ENS.

Can ENS be treated?

The removed tissue doesn't grow back. Implants can restore some volume, and stem cell approaches are being studied, but their effectiveness is not proven yet. Humidification can ease dryness.

Is it "all in my head"?

No. ENS is linked to physical changes in the nose. Living with it can also affect mood and sleep, which is why support matters too.

Overview of ENS by patient advocate Barbara Schmidt.

The mechanisms of ENS, an AI-generated summary of this article.

References (5)

Investigation of the abnormal nasal aerodynamics and trigeminal functions among empty nose syndrome patients. Li C., Farag A.A., Maza G. et al., Zhao K.
Empty Nose Syndrome Pathophysiology: A Systematic Review. Sozansky J., Houser S.M.
Submucosal glands, Wikipedia.
The nasal cycle in health and disease. Hanif J.
Sataloff's Comprehensive Textbook of Otolaryngology: Head & Neck Surgery. Sataloff R.T., chapter 19, p. 286.

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