Daytime Sleepiness – Finding the Cause
Updated: 1 day ago
Do you feel tired all the time no matter
how much sleep you get?
Daytime sleepiness has a significant impact on quality of life. People with daytime sleepiness struggle with social, academic and work demands, they are at risk of motor vehicle and workplace accidents and generally have poorer health than comparable adults.
Accurate diagnosis is important, not only because of the negative impacts of sleepiness and its root causes on health and social function but because excessive sleepiness is generally remediable with appropriate treatment [1]. The list of possible causes of excessive daytime sleepiness spans virtually every major area of medicine, neurology and psychiatry. A clear, detailed history is invaluable in negotiating these numerous diagnostic considerations [2].
To help with investigating daytime sleepiness, we’ve compiled a list of known causes and routine tests. Please note: there are numerous possible causes, this is by no means a complete list. It is only intended as a guide to assist you and your doctor find the cause of your excessive daytime sleepiness.
SLEEP DISORDERS
Behavioural sleep deprivation The most common cause of daytime sleepiness is insufficient sleep. Poor sleep habits may contribute to insufficient sleep. Sleep-related breathing disorders
Sleep apnea. Residual sleepiness in treated obstructive sleep apnea. Upper Airway Resistance Syndrome.
Other sleep disorders
Includes circadian rhythm sleep disorders (Delayed Sleep Phase Syndrome, shift work disorder), REM Sleep Behaviour Disorder and other Parasomnias, Post-traumatic hypersomnia (following head trauma or illness) Insomnia, Narcolepsy. Also sleep-related movement disorders (Periodic Limb Movement Disorder, Restless Legs Syndrome).
PSYCHIATRIC
Mental health conditions Including Depression, Anxiety, Bipolar Disorder.
MEDICATIONS EFFECTS
Includes prescription, non-prescription, and drugs of abuse. *refer to list of medications below.
MEDICAL CONDITIONS
Including head trauma, stroke, cancer, inflammatory conditions, encephalitis, neurodegenerative conditions (eg: Parkinson's Disease, myotonic dystrophy etc), Chronic Fatigue Syndrome (CFS/ME), Fibromyalgia, Hypothyroidism, Hashimoto’s thyroiditis, Ehlers-Danlos Syndrome, Arnold-Chiari Malformation, Multiple Sclerosis. Other medical conditions that are associated with sleep fragmentation can result in daytime sleepiness, including: arthritis, spondylosis, chronic pain of any nature, nocturnal angina, epilepsy, asthma, chronic obstructive pulmonary disease, alcoholism, urinary dysfunction and gastrointestinal disorders (e.g. peptic ulcer disease), gastro-oesophageal reflux and irritable bowel syndrome
OTHER CONSIDERATIONS
Hypersomnia that develops after a viral infection, including mononucleosis (glandular fever/mono), or Guillain-Barré syndrome. Patients may experience fatigue and hypersomnolence and can sleep most of the 24-hour day. The outcome tends to be favourable; however, the resolution may take months or even years [3].
Healthly long sleepers are people who require more sleep at night than normal. They may be misdiagnosed with idiopathic hypersomnia because of extremely long sleep episodes at night. These people are normally alert, however, once they have obtained their required amount of sleep [4].
Medication Classes Commonly Associated with Daytime Sleepiness
Alpha-adrenergic blocking agents
Anticonvulsants (e.g., hydantoins, succinimides)
Antidepressants (monoamine oxidase inhibitors, tricyclics, selective serotonin reuptake inhibitors)
Antidiarrhea agents
Antiemetics
Antihistamines
Antimuscarinics and antispasmodics
Antiparkinsonian agents
Antipsychotics
Antitussives
Barbiturates
Benzodiazepines, other γ-aminobutyric acid affecting agents, and other anxiolytics
Beta-adrenergic blocking agents
Genitourinary smooth muscle relaxants
Opiate agonists and partial opiate agonists
Skeletal muscle relaxants
Routine tests to consider for causes of daytime sleepiness
Thyroid tests should include: TSH, Free T3 (FT3), Free T4 (FT4), Reverse T3 (rT3), and thyroid antibodies for Hashimoto's Thyroiditis
Nutrient deficiencies including vitamin D (25-Hydroxy), B12 and serum folate, magnesium, zinc, iodine and selenium
Iron studies: Iron, TIBC, %Sat, Ferritin
Carnitine panel: free, total, esterified, esterified/free
C-Reactive Protein
Complete Blood Count
Complete Metabolic Panel (glucose, sodium, creatinine, etc)
Cortisol (preferably 8 am spot cortisol or 24-hr urinary cortisol)
Excessive daytime sleepiness is common, and identifying its underlying cause can be difficult. However, idiopathic hypersomnia should not be used as a default diagnosis when the cause remains unclear. Doing so risks misdiagnosis, inappropriate treatment, and leaving the actual cause unidentified and untreated.
Idiopathic hypersomnia is diagnosed by recognising its characteristic clinical features and carefully excluding other explanations. When these features are not well understood, or other possible causes have not been adequately investigated, an incorrect diagnosis may be made.
"Idiopathic hypersomnia is probably one of the most frequently overdiagnosed sleep disorders because there is a tendency to classify in this category all hypersomnias that do not fit the criteria of either narcolepsy or the sleep apnea syndrome." 5
Click here for a copy of our "Excessive Daytime Sleepiness - Finding the Cause" Factsheet or try this link https://www.hypersomnolenceaustralia.org.au/_files/ugd/a1218b_db6abe7f2c1d40239831e1707205cf64.pdf
1, 2. http://brain.oxfordjournals.org/content/124/8/1482.long 3, 4, 5. http://www.beatcfsandfms.org/references/IdiopathicHypersomnia.html First published on Hypersomnolence Australia's website in July 2015
