Upper Airway Resistance Syndrome

Overview

Upper airway resistance syndrome (UARS) is a sleep disorder characterized by increased resistance to airflow in the upper airway during sleep, leading to frequent arousals and disrupted sleep patterns. Unlike obstructive sleep apnea (OSA), UARS does not typically involve complete airway obstruction or significant drops in blood oxygen levels. However, it can still result in excessive daytime sleepiness, fatigue, and reduced quality of life. UARS is considered part of the spectrum of sleep-disordered breathing and is often underdiagnosed due to subtle clinical signs and normal oxygen saturation during sleep studies.

Causes

UARS is caused by a partial collapse or narrowing of the upper airway during sleep, which increases resistance to airflow and leads to arousals. Contributing factors include:

• Abnormal upper airway anatomy (e.g., narrow nasal passages, enlarged turbinates, or a small jaw)

• Low muscle tone in the upper airway during sleep

• Obesity or excess tissue in the neck area

• Structural deviations such as a deviated nasal septum

• Increased nasal resistance due to allergies or chronic congestion

These factors lead to increased breathing effort, even without significant oxygen desaturation or apneas.

Symptoms

People with UARS may experience symptoms similar to those of other sleep disorders. Common symptoms include:

• Excessive daytime sleepiness

• Non-restorative sleep

• Morning headaches

• Chronic fatigue

• Difficulty concentrating (brain fog)

• Irritability or mood changes

• Frequent awakenings or restless sleep

• Snoring (often mild or positional)

• Light, fragmented sleep with frequent arousals

Children with UARS may present with hyperactivity, poor school performance, or behavioral issues instead of daytime sleepiness.

Diagnosis

Diagnosing UARS can be challenging because routine sleep studies may appear normal or show only subtle abnormalities. Key diagnostic tools include:

• Polysomnography (sleep study) – detects increased respiratory effort-related arousals (RERAs) without significant apnea or hypopnea

• Esophageal pressure monitoring – considered the gold standard, measuring increased negative pressure during inspiration

• Clinical evaluation – assessment of symptoms, physical examination of the airway, and sleep history

Because esophageal pressure monitoring is invasive and not widely available, diagnosis often relies on a combination of clinical suspicion and sleep study findings.

Treatment

The goal of UARS treatment is to reduce upper airway resistance during sleep and improve sleep quality. Common treatment options include:

• Positive airway pressure therapy (PAP) – CPAP or bilevel devices can keep the airway open during sleep

• Oral appliances – custom-fitted devices that advance the jaw and improve airway patency

• Surgical interventions – nasal or upper airway surgery for anatomical obstructions (e.g., septoplasty, turbinate reduction)

• Weight management – in overweight patients, reducing weight can improve symptoms

• Allergy management – treating nasal allergies to reduce inflammation and resistance

• Sleep hygiene – optimizing sleep habits and sleeping position, especially avoiding supine posture

Prognosis

With appropriate treatment, the prognosis for individuals with upper airway resistance syndrome is generally good. Most patients experience significant improvement in sleep quality, daytime alertness, and overall well-being. Early recognition and management are important to prevent the development of more severe forms of sleep-disordered breathing, such as obstructive sleep apnea. Long-term adherence to therapy, particularly PAP or oral devices, is crucial for sustained benefits.