A brief overview of sleep disorder diagnosis, part 1

Over 80 major sleep disorders exist. This number also keeps changing and differs widely depending on the source and classification system you are using. For a psychiatrist, there are about 3 major classification systems to keep track of (Table 1).

Table 1. Major classification systems

DSMDiagnostic and Statistical Manual of Mental Disorders5American Psychiatric Association2013
ICDInternational Statistical Classification of Disease11World Health Organization2019*
ICSDInternational Classification of Sleep Disorders3American Academy of Sleep Medicine2014

*considered a preview, for implementation in 2022.

Sleep disorders encompass many fields, if not all, of medicine. Its diagnosis and management starts already at your primary care physician (or general practitioner) and extends into the fields of Neurology, Psychiatry, Respiratory Medicine, Cardiology, Ear Nose and Throat specialists and others. A brief overview of the roles and function of some of these care providers follows in Table 2.

Table 2. Various medical specialities involved in diagnosis and management of sleep disorders

General Practitioner Early detection, screening and detection of general medical conditions that may affect sleep and alertness (thyroid, kidney, brain, respiratory, adrenal, and other conditions such as vitamin deficiencies, obesity), choice of appropriate medication for general medical conditions (commonly used medication may cause insomnia, drowsiness or alter sleep in various ways, e.g. antihypertensives commonly cause insomnia), referral to an appropriate specialist, promotion of good sleep hygiene and the use of appropriate special investigations (blood tests, polysomnography/sleep study).
Respiratory MedicineLung disease such as Asthma, Chronic Obstructive Airway Disease (also known as emphysema or COPD), and other may severely alter the ability to fall asleep (breathlessness or treatment of the aforementioned disorders may cause severe insomnia) or stay asleep (altered ability to maintain the optimum blood oxygen saturation level ≥ 90%) may cause patients to wake up gasping for air, or simply insidiously alter normal sleep architecture (periods and duration of different phases of sleep during a normal night’s rest) and cause severely unrefreshing sleep.
CardiologyUnstable cardiac disease can lead to sleep-disordered breathing. Cardiac failure might also cause difficulty breathing, especially when lying down. This is called orthopnoea. People suffering from this condition may wake up short of breath that is relieved with a change in posture to the upright. Chronic sleep deprivation also increases the prevalence of cardiovascular disease.
Ear, Nose and ThroatThe upper airways are perhaps most implicated with sleep-related breathing disorders. Obstructive sleep apnoea (OSA) is amongst the most common sleep disorders and is becoming more relevant with increasing rates of obesity worldwide. Obesity is by no means the only cause of OSA. Other causes are often anatomical in origin, e.g size and shape of the tongue, large tonsils, dental/jawbone related, etc. Something as common as rhinitis or nasal septal defects may further worsen sleep apnoea or have their own effects on sleep architecture. In some cases, surgery might be indicated along with medical optimization of comorbid conditions, e.g. appropriate use of intranasal corticosteroids. In cases where surgery is not indicated (e.g. gold standard of treatment being medical management first, unstable medical condition, age, prior surgery have failed, patient preference, etc.) the use of CPAP (Continuous Positive Airway Pressure) devices may be indicated.
NeurologySome sleep disorders are best treated by a neurologist. These include sleep related movement disorders (periodic limb movement disorder, idiopathic restless leg syndrome), nocturnal epilepsy, neurological conditions affecting muscular activity (myasthenia gravis, motor neuron disease, etc), Parkinson’s Disease/PD (drugs used to treat commonly cause insomnia and somnolence, REM sleep behaviour disorder/RBD is commonly associated with PD and other neurodegenerative disorders), Narcolepsy and many more.
PsychiatryI cannot think of a single psychiatric disorder that is not linked in some way to the way we experience sleep. In my experience, the most common conditions linked to sleep disturbances are Depressive Disorders, Adjustment Disorders, Anxiety disorders, Bipolar Disorder, Substance use disorders, ADHD and Neurocognitive Disorders (Dementia and Delirium). Psychotropics can often either cause insomnia or daytime somnolence. These effects are exacerbated by drug interactions, dose, metabolism/pharmacogenomics (certain individuals will either rapidly or slowly metabolise certain drugs depending on liver enzyme expression). ‘Primary’ sleep disorders may also exist in the absence of other mental health conditions. This includes parasomnias (abnormal behaviour during sleep), insomnia disorder / primary insomnia, hypersomnolence disorder and many others.

Only peeking at the above lists might seem daunting to patient and clinician and might seem impossible to find the correct place to start looking for a diagnosis or treatment. I disagree, diagnosing a sleep disorder already starts at home. Always exclude contributing effects of poor sleep hygiene first, hence the plethora of previous posts purely about that topic. Get a detailed account of your sleeping habits. More data always makes the clinician’s job easier, this could include keeping a sleep diary (there are many apps available, or free online versions such as the one I made, but the humble piece of paper would do just fine). A bed partner’s or caregiver’s detailed account, or even better – video evidence of the suspected abnormal sleep behaviour will further aid the diagnosis. Thereafter you should visit your primary care physician to present your complaints. After a detailed history taking, thorough physical examination, and if needed requesting appropriate investigations your general practitioner may already know what the correct treatment should be or he/she may refer you to an appropriate specialist for further management. If you are already known with a condition that affects sleep, you should visit your treating specialist clinician with updated information and review of your condition.

More information will follow in future posts.

As always, wishing you good sleep.

Dr Schalk Wiehan Van Der Merwe

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