Sometimes people have a problem with breathing during sleep that is not diagnosed as obstructive sleep apnea (OSA) after they've had a sleep study.
Upper airway resistance syndrome (UARS) is a form of obstructive breathing during sleep which only yields a partial blockage of the airway and does not result in low oxygen levels in the bloodstream.
What is upper airway resistance?
It can include snoring, but the syndrome that defines UARS doesn't necessarily lead to snoring. With upper airway resistance, the airway narrows so much that the muscles of breathing along the ribcage and the diaphragm work double duty to ensure a complete inhale. Imagine breathing through a straw and you can see how it might be harder to breathe.
These conditions create what the Ohio Sleep Medicine Institute refers to as "snore arousals." Technically speaking, these are respiratory event related arousals (RERAs): arousals caused by resistance in the airway which do not result in oxygen desaturation. They are accounted for during sleep studies along with apneas and hypopneas in what is known as the Respiratory Distress Index (RDI).
While there's no fear of oxygen-deprived blood due to RERAs, those who have them frequently still struggle to achieve deep sleep. They tend to suffer from sleep fragmentation, which is, in its own way, dangerous. Night after night of broken sleep can lead to the same side effects as insomnia and sleep apnea, such as mood swings, excessive daytime sleepiness, high blood pressure, and drowsy driving.
What causes UARS?
Like OSA, UARS is caused by faulty mechanics, such as blockages in the airway due to:
an overlarge tongue, adenoids, or uvula
narrow upper airway passages
a high narrow palate or an overbite
related respiratory ailments (sinus and nasal allergies or chronic rhinitis), which swell the mucous membranes lining the airways, thereby narrowing them
a deviated septum, swollen turbinates, nasal polyps, or collapsed nasal valves
edema (swelling) anywhere in the body: it redistributes as the body reclines, sending fluid into the neck which can mechanically disrupt breathing
pregnancy, due to swelling and softer upper airway tissues
How else is UARS distinguished from sleep apnea?
Here are some other factors that doctors consider during diagnosis:
OSA prevails in men, but women are more likely to suffer from UARS
OSA is more common in older people, while UARS occurs in patient of all ages, even the very young
OSA often accompanies someone with obesity, whereas UARS sufferers often have normal BMI or are even underweight
People with UARS suffer more from frequent awakenings and difficulty resuming sleep than those with OSA
People with UARS do not always snore, whereas snoring or gasping is a common marker of OSA
What happens when UARS is left untreated
The discovery of UARS as a sleep breathing disorder happened at Stanford nearly 25 years ago, and yet diagnosing and treating it is still inconsistent, at best.
Patients observed for the obvious signs of sleep apnea showed none, yet they were still tired all the time and suffered physically and mentally.
Doctors, lacking any conclusive evidence of a sleep disorder that insurance would be willing to reinburse treatment for, often overlooked the diagnosis or, because they were looking for sleep apnea, did not diagnose anything in its place when data showed differently.
The Ohio Sleep Medicine Institute refers to UARS as "the orphan child of sleep medicine" because its diagnosis escapes some doctors, who don't always agree on how to define it, or don't always offer treatment when it can be confirmed.
To make matters worse, UARS is also often misdiagnosed as chronic fatigue syndrome (CFS), fibromyalgia, depression, mood disorder, or migraine by primary care physicians who do not consider the value of having their patients undergo a sleep study to rule out a sleep-breathing disorder. Other impacts from untreated UARS include:
Acid reflux, heartburn, gastroesophageal reflux disease (GERD), or laryngopharyngeal reflux disease (LPRD)
Bruxism (teeth grinding and jaw clenching)
Excessive daytime sleepiness
High (or low) blood pressure
Irritable bowel syndrome (IBS)
Morning nasal congestion
Non-refreshing sleep (or, waking up tired)
Parasomnias like confusional arousal, sleepwalking, sleeptalking, sleep paralysis
There's also controversy as to whether UARS is a sleep disorder that's distinct from OSA. Some doctors argue that it is, while others believe that, if left untreated, it can gradually progress, in its "harmless" position in the hierarchy of sleep breathing disorders, from "benign snoring," to UARS to, ultimately, sleep apnea.
Meanwhile, about 1 in 7 patients having sleep tests to reveal sleep breathing problems are still shown to have UARS and still need help breathing at night.
Fortunately, things have changed since the early 1990s; the American Academy of Sleep Medicine (AASM) identified it as a sleep breathing disorder and included practice parameters for treating it in 2005.
Insurance is starting to recognize UARS and provide for its therapies as well, which include use of continuous positive airway pressure (CPAP), an oral appliance, weight loss, positional therapy, and some surgical approaches.
At Sound Sleep Health, we look at the full range of possibilities when it comes to sleep breathing disorders. Contact us today to get a free sleep assessment to determine if you might potentially suffer from UARS:
American Academy of Sleep Medicine
Current Opinion in Pulmonary Medicine
Journal of Clinical Sleep Medicine
Ohio Sleep Medicine Institute
Stanford Center for Sleep Sciences and Medicine