Upper Airway Resistance Syndrome: The Silent Epidemic 

Cindy is a 34-year-old woman who originally came to see me about her recurrent sinus headaches. She had taken multiple antibiotics with only temporary relief. She also was taking and antidepressant for the past 2 years. She complained of intense fatigue and daily headaches, along with recurrent diarrhea, especially when she was stressed. She always wore socks and mittens at night to keep her cold hands and feet warm, even in the summer. Her father snored like a train before dying of a stroke in his 50s. Her sleep study was “normal” and was told that she didn’t have obstructive sleep apnea. 

Physicians are stumped every day whenever they see someone like Cindy. They’ll usually treat each individual symptom, but with only temporary results. Once obstructive sleep apnea has been “ruled out,” no one will ever think that this may still be a sleep-breathing problem, until someone examines her upper airway.

Cindy’s upper airway was eventually examined by using a flexible fiber-optic camera with her lying on her back. Not too surprisingly, the space behind her tongue was only 1-2 mm wide. This confirmed her history that she can only sleep on her stomach. She also had a deviated nasal septum and flimsy nostrils that caved in every time she breathed in through her nose. 

UARS 

Upper airway resistance syndrome, or UARS, was first described by one of the pioneers in sleep medicine, Dr. Christian Guilleminault at Stanford University.1 He studied young thin men and women who were exhausted despite sleeping 8 hours and having a “normal” sleep study. In his classic experiment, he placed thin pressure sensors inside the patients’ esophagus (food passageway) and measured pressures during sleep. What he found was that all these people had multiple episodes of only partial obstruction but severe respiratory efforts that lead to significantly negative pressures in the esophagus. It is like trying to breathe in all night through a flimsy straw. After multiple similar episodes, patients would wake up from deep to light sleep, which is called an arousal in sleep medicine jargon. This lead to severely fragmented sleep, but with minimal apneas or hypopneas.

Since Dr. Guileminault’s paper, numerous other researchers have described a common pattern amongst people with UARS.2,3 They are relatively young and thin, and are likely to have depression or anxiety, cold hands, or feet, have headaches, irritable bowel syndrome, and low blood pressure with dizziness, and lightheadedness.

Dr. Guilleminault also reported that about 5 to 10% go on to develop obstructive sleep apnea every year, especially if they gain weight. He also has been known to say that while people with obstructive sleep apnea have diminished nervous systems, people with UARS have an intact nervous system. You can also have a combination of both conditions during your transition period. I have had dozens of post-menopausal, hypertensive, overweight women tell me that then they were in their 20s, they were stick thin, or had low blood pressure.

This is an important concept to review. Any form of obstructed breathing will lead to a fight or flight response, causing you to react immediately. If you obstruct even for a second or two at night, you will likely wake up right away. In patients with sleep apnea, due to years of chronic vibrations from snoring, it is thought that the protective reflexes in your throat become numb, like how your hand feels after using a vibrating tool, such as a sander. It is been shown that people with sleep apnea are not able to distinguish two points in the throat as easily as people without obstructive sleep apnea.4 In the ENT research literature, increased levels of acid reflux exposure in the voice box is associated with lowered protective reflexes that close the vocal cords when irritated by any stimulation.5 What all these studies show is that all the protective upper airway reflexes (pressure, chemical and sensation related) are likely more diminished in people with obstructive sleep apnea. This may be one reason why an apneic can stop breathing for 30 to 50 seconds at a time without waking up. What causes the person to wake up is not low oxygen levels, but the high levels of carbon dioxide (CO2). 

UARS patients, on the other hand, wake up normally, or abnormally too quickly. When I say wake up, I do not mean wake up wide awake. It can be from deep to light sleep, or completely awake. You’re more likely to stop breathing when your throat muscles are more relaxed, especially in deeper levels of sleep.

This is also why patients with UARS send to be over-reactive to almost everything. The nervous system is hypersensitive to various triggers such as weather changes, sounds, lights, chemicals, scents, odors, fumes, or even emotions. Think of yourself being in that “fight or flight” state all the time. If you remember watching a suspense-filled horror movie, you know what I mean. 

Imagine if you went to the zoo, and a tiger escapes and is running towards you. What is your first reaction? Most people would run away as fast as possible. Some people would fight. When you’re either running or fighting, your lowest priority is to digest or reproduce. All your blood flow, energy and resources are redirected to your cardiovascular system, your central core muscles, and away from your digestive system, reproductive organs, and even your skin. These “unessential” organs are called end-organs. If you suffered a cut during battle, you don’t want to bleed too quickly, so the blood vessels in your skin normally constricts during these type of situations. Hormonally, neurologically, everything is geared toward saving your life, and not resting, digesting, healing or building up your body.

The Migraine Connection

Notice that when some or every part of your nervous system is overly sensitive, it’s similar to having a migraine. I am not talking about migraine headaches in particular. A migraine can happen whenever any part of your body, whether it is your head, ears, nose, sinuses, stomach, or hands, become overly sensitive to any form of stimulation.6 This is how you can have what may seem like a “sinus infection,” but it is really a migraine. In situations like what happened with Cindy, studies have shown that in the vast majority of cases, and it’s likely a sinus migraine.7 Another example is if you have an inner ear migraine. You can have hearing loss, dizziness, ringing or balance problems. If you have a migraine with your stomach, then you can have pain, nausea, bloating, constipation or diarrhea. 

The Atrial Natriuretic Peptide (ANP) Connection

An interesting association was recently described between UARS and a hormone called atrial natriuretic peptide (ANP).8 Whenever you stop breathing, even for a few seconds, excessive negative pressures are created within the chest wall cavity. As your diaphragm drops and your ribs expand outwards, your lungs would normally inflate and get bigger, allowing you to inhale air and absorb oxygen. If your throat or upper airway is partially or totally obstructed, your lungs won’t expand, but your heart’s walls may expand. This stretching action is known to stimulate ANP production, which is a normal physiologic process—if you have too much fluid returning to your heart, then you’ll want to make more urine to lower volume within your blood vessels. 

In people with UARS, ANP is increased, but the kidneys do not normally respond. However, as the breathing pauses get longer and longer, and as oxygen levels drop more, ANP begins to make your kidneys produce more urine. This is one reason why many people with obstructive sleep apnea wake up to go to the bathroom at night, sometimes multiple times. It has been shown that when people wake up, it is not usually due to too much urine, but due to the fact that you’ve stopped breathing and when you wake up, you think you have to go to the bathroom. Usually, it is not a lot of urine.

One of the known properties of ANP is its’ ability to lower blood pressure, as well its’ weight loss properties. This may explain why many people with UARS are relatively thin, and tend to have blood pressure on the low side, or they get dizzy or lightheaded when getting up too quickly.

Treating UARS 

The treatment options for OSA and UARS are exactly the same: Conservative lifestyle and dietary changes, CPAP, oral appliances and surgery.

Obviously, most people with UARS usually won’t need any further weight loss. Typically, they eat a healthy diet, exercise regularly, and try to sleep 7 to 8 hours every night. They don’t abuse their bodies. However, they see their doctors for multiple different problems, with no significant help with their problems that help long-term.

One of the biggest hurdles for people with UARS is that unless you officially have an OSA diagnosis, it’s not likely to be covered by your insurance carrier. The bare minimum score that you’ll typically need for a sleep apnea diagnosis is 5 apneas or hypopneas per hour, and you have other symptoms or medical conditions such as daytime fatigue or high blood pressure. However, this definition assumes that an apnea or hypopnea lasts at least 10 seconds or longer. However, if you stop breathing 25 times every hour, and these episodes last from 1 to 9 seconds, then your official sleep study AHI score will be 0.

In general, UARS patients can’t tolerate CPAP as well as people with OSA. In fact, numerous studies have shown that people with mild levels of OSA don’t tolerate CPAP as well as those with severe OSA. This makes sense, since having an overly sensitive nervous system can make you wake up to any degree of irritation, such as a mask on your face, air blowing in your nose, or noises from the CPAP machine. 

Regardless, it’s important to at least consider trying a CPAP machine, even if you have to pay out of pocket for it. It can run anywhere from $300 to 800. Oftentimes, I’ll give the patient a prescription for an automatic PAP machine, which calibrates the pressure on its’ own. 

If you have any degree of nasal congestion, it’s important take the necessary steps to breathe better through your nose, whether addressed medically or surgically. It’s been shown that improving nasal breathing can help patent tolerate and benefit from CPAP or dental devices. Please refer to the chapter on ways to improve nasal breathing.

Dental appliances are another good option for UARS, as long as the tongue is found to move forward when pushing the lower jaw forward. This can be confirmed with an office endoscopy, where a small flexible camera is passed through your nose while you’re on your back, to look at the spec behind your tongue. If the space behind your tongue opens up significantly while thrusting your jaw forward, then you’ll be a good candidate. Please refer to the chapter on dental appliances for a more detailed description for these devices. Even if you are an ideal candidate for these devices, it’s another matter when it comes to whether or not you can tolerate having something in your mouth.

Because of the high costs without insurance coverage, surgery is not an option that many people choose to undergo. However, it’s still a medically and surgically acceptable option, regardless of insurance coverage. Obstructed breathing needs to be addressed, whether or not it’s covered by insurance.

You may be wondering how Cindy did. She refused CPAP, but was willing to pay for an oral appliance. Six weeks after using her dental appliance, she was happy to report to me that although not completely cured, she was sleeping better and feeling significantly better, with much less headaches. Even her diarrhea and cold hands had improved significantly. 

References

1. Guilleminault C, Stoohs R, Clerk A, Cetel M, Maistros P. A cause of excessive daytime sleepiness. The upper airway resistance syndrome. CHEST. 1993;104(3):781–787.

2. Bao, G., & Guilleminault, C. (2004). Upper airway resistance syndrome-one decade later. Current opinion in pulmonary medicine, 10(6), 461-467.

3. Gold AR, Dipalo F, Gold MS, O’Hearn D. The symptoms and signs of upper airway resistance syndrome: a link to the functional somatic syndromes. CHEST. 2003;123(1):87–95.

4. Guilleminault C, Li K, Chen N-H, Poyares D. Two-point palatal discrimination in patients with upper airway resistance syndrome, obstructive sleep apnea syndrome, and normal control subjects. CHEST. 2002;122(3):866–870.

5. Aviv, Jonathan E., et al. “Laryngopharyngeal sensory deficits in patients with laryngopharyngeal reflux and dysphagia.” Annals of Otology, Rhinology & Laryngology 109.11 (2000): 1000-1006.

6. Buchholz, David. Heal your headache: The 1-2-3 program for taking charge of your pain. Workman Publishing, 2002.

7. Eross E, Dodick D, Eross M. The Sinus, Allergy and Migraine Study (SAMS). Headache. 2007;47(2):213–224. doi:10.1111/j.1526-4610.2006.00688.x.

8. Wardly, Deborah E. “Atrial natriuretic peptide: beyond natriuresis to an understanding of the clinical findings in upper airway resistance syndrome.” Med Hypotheses Res 8 (2012): 1-38

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5 thoughts on “Upper Airway Resistance Syndrome: The Silent Epidemic 

  1. Are you aware of a connection between Ehlers-Danlos Syndrome (a genetic condition that results in the weakening of arterial walls and the GI lining) and Upper Airway Resistance Syndrome? I have EDS and noted that several of the symptoms you listed for UARS are parallel with those of EDS: (e.g. low blood pressure with dizziness, irritable bowel syndrome, and thin body build). It seems to me that the etiology of these two conditions could be similar, as well. Do you know of anyone who is studying this relationship, if it exists?

  2. Sue,

    Any condition that leads to poor upper airway skeletal development can lead to UARS or OSA. This is why many of the familiar “syndromes” are prone to sleep-related breathing disorders.

  3. Dr. Park,

    Is there any particular dental appliance that is recommended for treatment of UARS or OSA in a patient who has Ehlers Danlos syndrome but is not helped much by a CPAP machine due to chronic sinus congestion? Thank you!

  4. Sue,

    My general philosophy is to find a good sleep dentist that’s familiar and comfortable with multiple mandibular advancement devices, rather than focus on one particular brand. There are pros and cons to all the various options.