I’m always tired, Doc

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“I’m always tired, Doc.”
Well, join the club, I’m always tempted to say. It doesn’t seem like a day goes by without at least one poor patient slumping down in their chair and telling me about their permanent fatigue.

Feeling tired is such a common symptom in today’s busy society that it’s almost a badge of honour. And there are many different causes of fatigue, things like iron deficiency, low thyroid, viral illness, chronic fatigue syndrome, mental health issues. But today I want to discuss sleep apnoea.  I have a sneaky suspicion that a lot more of my tired patients have it than I previously realized. The Healthy Sleep Foundation is a great resource for further information. This is their fact sheet on Sleep Apnoea.

What is sleep apnoea

Sleep apnoea occurs when there is some sort of airway obstruction during sleep. When this happens, the patient actually stops breathing, and their sleep is interrupted as their body automatically wakes them up to start breathing again. Obviously, with this constant sleep disturbance, sleep quality is affected.

Why does it occur

Your airway is maintained by nerves to the muscles around your airway that keep it open. When you are awake, these muscles are always activated, working to keep the otherwise soft and floppy pharynx (since it has no cartilage or bone) open. However, when you sleep, the nerves that keep these muscles activated reduce in their activity, and this can allow your airway to collapse. This is more likely with the following:

  • Being obese- this can cause fat deposition in the soft tissues of the airway, narrowing it further. Being obese can also reduce lung volumes in the lying down position, which reduces the traction on the pharynx and makes it even more likely to collapse
  • Have nasal issues- like nasal polyps or a septal deviation. This can result in mouth breathing at night, causing the tongue to flop back over the airway and block it. Increased nasal resistance also increases the likelihood of the pharynx collapsing due to negative pressures.
  • Certain anatomical features of the jaw shape and position can also reduce the airway
  • Family history- there is definitely a genetic predisposition to the condition

What are the symptoms?

Patients are often snorers, but not always. Sometimes their partners might report sudden gasping or snorting, which can be a sign their body waking up to breathe again. But the most common reported symptom is excessive tirednessfatigue, or sleepiness. There is a questionnaire called the Epworth Sleepiness Scale which can be done to assess daytime sleepiness and consider testing for sleep apnoea. Essentially it is a propensity to dozing which is out of the ordinary- for example, falling asleep while driving or eating. But some patients may score normally on this scale and still have sleep apnoea.

What complications can it cause?

 Untreated sleep apnoea can cause a whole host of problems outside of simply feeling tired (although that is pretty significant!). Otherwise it can contribute to, or is a risk factor for:

  • Hypertension
  • Coronary artery disease
  • Heart failure
  • Cardiac arrhythmias
  • Stroke
  • Diabetes
  • Depression
  • Injuries due to fatigue (for example, car accidents and workplace injuries)

What tests can be done? 

Aside from standard tests to exclude other causes of sleepiness, the most important diagnostic test for sleep apnoea is a sleep study. This can be done in a lab or at home. You wear sensors and equipment, and a computer records a number of readings while you sleep. You have an EEG done, which traces the electrical activity of your brain to detect your different sleep stages, and sensors check your oxygen saturations in your blood, changes in airflow, muscle movements, and cardiac rhythms. Using this data, the lab can calculate whether you have having apnoeas (referring to a cessation in breathing), and how many.

How is it treated? 

If you are identified as having sleep apnoea (generally considered when you are recorded has having more than 15 episodes per hour of sleep), then treatment is twofold- treating the cause(s) and treating the symptoms. Obviously, if it is largely genetic/anatomical there is not a lot that can be done to treat the causes, but if you are overweight or have nasal congestion issues, these can be addressed. To treat the symptom, we generally rely on CPAP machines, although there are some oral appliances such as mandibular splints which apparently can reposition the jaw to prevent pharyngeal collapse.

How does a CPAP machine work?

CPAP stands for Continuous Positive Airway Pressure, which is exactly what it does- it delivers positive pressure that acts as a mechanical splint to keep the airway open. Air is delivered through the mask, and this air creates the pressure. There is no oxygen delivery.

So, if this sounds like you, or you would simply like to check if there are any underlying medical causes for your constant tiredness (not just the stresses of modern living!), then see your GP for testing. Of course, you are also welcome to see me to discuss your symptoms, or if you already have sleep apnoea and would like to discuss weight loss management.

Reference:
In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison’s Principles of Internal Medicine, 20e Chapter 291: Sleep Apnea New York, NY: McGraw-Hill;  Accessed October 15, 2018.