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Sleep disorders Module 149: January 2010
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Sleep medicine
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A wide range of sleep disturbances present in general practice – especially among older people. GPs
should play a leading role in identifying the causes of insomnia and in early diagnosis, management
and patient education in disorders like restless legs syndrome, narcolepsy and sleep apnoea
(This module was facilitated by Drs Claire Dalton and Shaun O’Keeffe)
Sleep is an important physiological process with restorative functions. Disorders of sleep are among the most
common disorders in the general population and are particularly common in older people.
Normal sleep
Although there is considerable individual variation, the
average adult needs approximately 8.3 hours of sleep per
night, with the time to fall to sleep (sleep latency) at 10
minutes. Sleep can be divided into two categories: rapid
eye movement sleep (REM) and non-REM sleep. Each of
these can be connected closely to specific CNS activity.
REM sleep, accounting for 20% of total sleep time in most
adults, is characterised by muscle atonia, episodic rapid
eye movements and a low voltage, fast frequency EEG pattern. Most dreaming occurs in this stage. Non-REM sleep
can be divided into three further stages: N1, N2, and N3,
the threshold for arousal rising with each stage. N3 (which
replaces stages 3 and 4 in the old classification) is also
called slow-wave sleep. Sleep proceeds in cycles of REM
and non-REM sleep, the order normally being N1 → N2 →
N3 → N2 → REM. There is a greater amount of deep sleep
(stage N3) early in the night, while the proportion of REM
sleep increases later in the night and just before natural
awakening.
Sleep wake cycles are controlled by complex internal
clocks as well as by behaviour. Although many neurotransmitters may be involved in regulating sleep, much recent
interest has focused on adenosine whose release is triggered by prolonged neural activity in the brain’s arousal
centers and which may act as a ‘fatigue factor’ by slowing
down neural activity in the arousal areas. Release of melatonin, the ‘hormone of darkness’ from the pineal gland is
also important.1
Taking a sleep history
Although formal sleep studies with polysomnography are
important in investigating some sleep disorders such as
sleep apnoea, a thorough history should lead to diagnosis,
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Table 1
Causes of disturbed sleep
• Poor sleep hygiene/behaviours
• Medical illness and medications
• Circadian rhythm changes with age
• Primary sleep disorders
• ‘Learned’ or chronic insomnia
• Mood disorders
• Neurodegenerative conditions
and hence the most appropriate management in the majority of patients presenting with sleep problems.
The history should include questions about the duration
of the sleep disturbance: for example, insomnia lasting
days or weeks is more likely due to a remediable medical
or environmental stressor. The pattern of insomnia is often
related to the aetiology: thus, for example, difficulty falling
asleep may be a consequence of anxiety or of restless legs,
while early morning waking is classically associated with
depression.
Sleep habits and sleep beliefs are also important: for
example, daytime napping or going to bed too early may
limit sleep duration at night. Discussing the problem with
the patient’s bed partner may be helpful in identifying
problems such as snoring, parasomnias or periodic leg
movements.
Numerous medical conditions may result in difficulty
sleeping. Pain, especially due to musculoskeletal disease,
is a common cause of sleep disturbance. Vigorous treatment of dyspnoea due to cardiac or respiratory disease,
using diuretics early in the day or long-acting beta agonists
before bed, may help alleviate insomnia. Similarly, identification and treatment of problems such as prostatism,
gastro-oesophageal reflux and pruritic skin conditions may
be helpful.
Patients suffering from Parkinson’s disease may have
urinary frequency and also have difficulties with getting
out of or turning in bed. Specific sleep disorders such as
restless legs syndrome and REM sleep disorders are also
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more common in parkinsonism as is sleep disruption due to
dopaminergic medications.
Insomnia is common in depression and may respond well
to sedating antidepressants. Sleep problems are particularly common and disruptive in those with dementia.2 These
include development of agitated behaviours in the evening
and night (sundowning) and disruption and even reversal of
the normal circadian pattern of sleep. Caregivers of such
patients may themselves experience considerable sleep disruption as a result of the patient’s difficulties.
Several medications may also affect sleep adversely
including alcohol, beta-blockers, caffeine, corticosteroids,
SSRIs, levodopa, diuretics, and fluorquinolones.
Primary sleep disorders include sleep-related breathing
disorders such as central and obstructive sleep apnoea;
hypersomnias of central origin such as narcolepsy; parasomnias due to disruptive arousals or partial arousals during
REM or non-REM sleep; and sleep-related movement disorders such as restless legs syndrome (RLS).
Sleep apnoea, RLS and REM sleep disorder are more
common in older people and often go undiagnosed. Narcolepsy usually begins during the 20s or earlier. However,
symptoms tend to be lifelong and it may be seen in ‘graduate’ older people or sometimes, usually if symptoms are
mild, diagnosed for the first time in later life.3
Non-REM parasomnias such as night terrors, sleepwalking, and sleep-talking occur during N3 slow-wave sleep and
are more common in younger people.
Insomnia
Insomnia can be defined as a difficulty falling asleep or
staying asleep or a disturbance in sleep quality that makes
sleep seem inadequate or unrefreshing. It is a symptom and
not a condition. Insomnia has many effects on health and
quality of life, with substantial direct and indirect costs to
society. This is particularly true of older people since not
only does the prevalence of insomnia increase with age, but
older people are especially vulnerable to adverse effects
from hypnotic medications used to treat the condition pharmacologically, including memory impairment and impaired
daytime performance. Large population studies show that
almost 60% of older adults report insomnia.4 Of these,
three-quarters are occasional sufferers with problems an
average of six nights per month, and the remaining quarter
have frequent insomnia, averaging 16 nights per month.
The reasons why insomnia increases with age are multifactorial, including changes in sleep architecture with ageing,
the effects of medical illness and medications, increased
prevalence of many primary sleep disorders and the effects
of social factors such as isolation and boredom.
Both the quantity and quality of sleep change significantly with ageing. Sleep efficiency, defined as the amount
of time asleep relative to the amount of time in bed, is
decreased to 70-80% compared to 90% or more in younger
adults. Total sleep time is reduced often to less than six
hours per night, with the ability to stay asleep being particularly affected. Slow wave sleep declines while light sleep
increases; hence older people are more likely to waken in
response to external stimuli during the night.4
Table 2
Sleep hygiene measures
• Maintain a regular waking and sleeping time
• Decrease the number/length of daytime naps or eliminate them if possible
• Aim to have some form of daily physical exercise but not
late in the evening
• Try to have exposure to daylight where possible
• Use the bed only for sleeping or sex
• Resolve concerns/ worries before bedtime
• Do not use the bed for reading/TV/telephone
• Avoid heavy meals late at night
• Limit or eliminate caffeine, nicotine and alcohol before
bedtime
• Create a comfortable environment with appropriate
temperature, lighting, clothing and quiet
• If unable to fall to sleep within 30 minutes or so, have a
relaxing activity to do
Another characteristic of sleep in old age is a phase
advance of the normal circadian cycle. The result is an earlier onset of sleep, followed by an earlier morning waking.
In some people this innate tendency is exacerbated by their
adopted behaviour.
It is one of life’s sad ironies that while many younger
people – trying to juggle work, family and a busy social
life – may wish that they could, and may try to get by with
less sleep, many older people, especially if lonely or bored,
may prefer to, and again may try to achieve the oblivion of
sleep for longer periods. The architecture of sleep at different ages is kind to neither. For older people, napping
by day and going to bed earlier than they used to will only
lead to more sleep inefficiency and even earlier waking
from sleep.
Management: Potential causes of insomnia, such as medical or psychological conditions or medications, should be
remedied whenever possible. Education about and interventions regarding sleep hygiene should be tried before any
pharmacological approach is considered.5 Implementing
good sleep habits is essential and helps create an appropriate environment for sleeping. The appropriate intervention
for a given individual depends on his or her habits, but
Table 2 shows the most important principles.
Sleep restriction therapy and cognitive behavioural therapy (CBT) are two useful behavioural interventions. There is
good evidence that both approaches are comparable or even
superior to sedative medications.
The most commonly used medications that are to treat
insomnia are benzodiazepine and non-benzodiazepine
sedative-hypnotic drugs (the ‘Z’ drugs). Sedating antidepressants or antipsychotics may be valuable in those with
specific indications but are less well studied in primary
insomnia. Studies in the developed world show that sedative hypnotic agents are used daily by about 20% of older
community dwellers and almost twice as many in long-term
care.6 All such drugs have the potential to cause addiction
and physical dependence with withdrawal symptoms if the
drug is not carefully titrated down. Side-effects common to
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Table 3
these drugs include day time fatigue, motor vehicle crashes,
cognitive impairments and falls and fractures. Older people
are more sensitive to these side-effects.7
Benzodiazepines bind unselectively to GABA type A receptor subtypes. They reduce the time to sleep onset and prolong
sleep time. However, they may worsen the quality of sleep
as they promote light sleep while decreasing time spent in
deep REM sleep. They also worsen sleep apnoea. Benzodiazepines can also decrease anxiety and have anti-epileptic
properties. Duration of action varies between medications.
Long-acting benzodiazepines should be avoided in older
adults because of longer duration of effect and an increased
risk in older people especially if the patient has additional
risk factors for adverse cognitive effects or falls.8
Non-benzodiazepine sedative-hypnotics such as zolpidem and zopiclone have a more selective action for the
α1 sub-unit on GABA type A receptors which is responsible for inducing sleep. Due to their greater specificity,
non-benzodiazepine agents are less anxiolytic and have less
anticonvulsant properties and should theoretically have a
cleaner side-effect profile.
The UK National Institute for Clinical Excellence (NICE)
concluded that “because there is no firm evidence of differences in the effects of zaleplon, zolpidem, zopiclone and the
shorter-acting benzodiazepines, NICE recommends that doctors should prescribe the cheapest drug, taking into account
the daily dose required and the cost for each dose”.
Restless legs syndrome
Restless leg syndrome (RLS) is a common lifelong sensorimotor disorder and is frequently undiagnosed. It appears
to have a higher prevalence in women and the elderly.
The condition, like other sleep disorders, has detrimental effects on sleep and also on daily function and quality
of life. Patients feel an intense, creeping sensation in the
lower extremities – particularly in the evening – which is
relieved by moving the legs.
RLS can be divided into primary and secondary forms.
There is thought to be a strong genetic influence in primary
RLS. Secondary forms are associated with iron deficiency,
pregnancy and renal failure. The four essential criteria for
diagnosing RLS are: an urge to move the extremities usually associated by unpleasant leg sensations; worsening of
symptoms at rest; partial or complete relief by activity; and
worsening of symptoms in the evening or night.9 Often the
sensations in the legs are described as crawling in nature.
Significant sleep disturbance occurs in over 90% of
patients and usually consists of difficulty getting to sleep.
In severe cases, patients may spend hours pacing the bedroom to relieve their leg sensations.
The majority of patients also have periodic leg movements, resembling the Babinski response, during sleep.
This most commonly manifests itself in the extension of
the big toe, dorsiflexion of the ankle, knee or hip every
20-40 seconds. Such movements are common in normal
older people and may be asymptomatic (at least for the
patient – bed partners may complain bitterly about being
kicked). They are more severe and frequent in RLS and may
lead to arousal.
Diagnostic criteria for
restless legs syndrome
• The urge to move legs with unpleasant sensations
• An increase or onset of symptoms with rest or inactivity
• Decreased symptoms on moving (eg. stretching)
• Increase in symptoms during the evening and night
• Variable course of symptoms
• Normal physical examination in idiopathic RLS
• Complaint of sleep disturbances
Differential diagnosis:
• Peripheral neuropathy
• Lumbosacral radiculopathy
• Hypnogenic myoclonus (sleep starts)
• Venous/arterial insufficiency
• ‘Painful legs and moving toes syndrome’
• ‘Growing pains’
Irish Sleep Society Guidelines 2007
A positive family history, often showing autosomal dominant inheritance with incomplete penetrance, occurs in a
third of patients, and a number of candidate genes have
snow been identified.
Clinically significant RLS is more common in older age,
occurring in about 5% of older people.10 Early onset (less
than 45 years) RLS is often slowly progressive, familial and
primary in nature. In contrast, older onset RLS is often rapidly progressive, sporadic and secondary to causes such as
iron deficiency, rheumatoid arthritis, end-stage renal disease,
neuropathy or medications such as SSRIs or neuroleptics.
Screening for iron deficiency is recommended for all RLS
patients with a cut off for serum ferritin of less than 50ng/l
(70ng/l may be a better cut-off for those with acute or
chronic inflammatory conditions) for identifying those who
may have iron deficiency and hence iron-responsive RLS.
Management: Oral iron therapy is an effective treatment
for RLS patients with iron deficiency; they should also
receive treatment for any underlying cause of iron deficiency.10 Intravenous iron may be helpful if patients are
intolerant of oral formulations.
Dopaminergic therapy is the best approach for those with
primary RLS sufficiently severe to warrant treatment.11 Levodopa produces a dramatic but short-lived improvement in RLS
symptoms. However, it is not recommended because with
prolonged treatment many patients show evidence of augmentation, where symptoms become more severe, involving
other body parts or appearing at new times, or of end-of-dose
rebound effects where symptoms recur during the night.
Direct dopamine agonists eg. pramipexole and ropinirole (tablets) and rotigotine (transdermal patch) are
instead the agents of choice, producing short and longterm improvement in symptoms with much less incidence
of augmentation. Dopamine agonists can be used for any
stage of RLS – mild, moderate or severe.
Gabapentin is helpful in those with painful variants of
RLS, especially due to neuropathy, while opioids are
useful in the most severe cases that are resistant to other
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approaches. Although often used, there is little evidence to
support use of benzodiazepines in this condition.
and to tolerate and considerable education and support
may be required.12
Sleep apnoea
Narcolepsy
Sleep apnoea is temporary interruption of breathing
during sleep and may be obstructive (upper airway occlusion), central (due to loss of central respiratory drive) or
mixed.
Common causes of central sleep apnoea in older people
include stroke, Alzheimer’s disease, heart failure, and uraemia. Respiration may be further depressed in such patients
by sedative-hypnotic medications and alcohol.
Obstructive sleep apnoea (OSA) is the most common
type of sleep apnoea in older as well as in younger adults.6
Episodes of airway obstruction lead to nocturnal oxygen
desaturation, interruption of sleep, a marked reduction of
REM sleep and daytime sleepiness. OSA has been associated in epidemiological studies with hypertension, stroke
and ischaemic heart disease.
The major risk factors for obstructive sleep apnoea in
younger adults (male sex, obesity and large neck circumference) are less predictive in older people.
The prevalence of OSA peaks in late middle age, and the
clinical severity and significance of OSA may be less in
older than in middle-aged people. Nevertheless, those with
clinically significant OSA benefit from diagnosis and treatment. Moreover, there is increasing interest in the potential
role for sleep apnoea in the pathogenesis of cognitive
impairment in older people.
Management: Measures such as weight loss and avoidance of smoking, alcohol and benzodiazepines may be
helpful. For those with clinically significant OSA, continuous positive airway pressure usually through a nasal mask
is the best approach.
However, many older people find this difficult to manage
Narcolepsy is a chronic neurological condition characterised by excessive daytime sleepiness and cataplexy.
Other symptoms include sleep paralysis, hypnogogic hallucinations, disturbed nocturnal sleep and associated sleep
disorders, parasomnias (eg. nightmares, night terrors, sleep
walking) and various cognitive symptoms.
Narcolepsy can cause a range of psychosocial difficulties
and there are accident and safety issues. It often presents
in the second decade and is therefore a lifelong disorder.
Early diagnosis is important. History should be structured
and detailed with the aim of identifying the symptoms and
assessing the severity of the condition. More than one sleep
disorder can co-exist. Treatment will focus on management
of excessive daytime sleepiness and also on dealing with
cataplexy. In conjunction with medication, good education
is also essential to help patients to deal with this condition.
As this is a lifetime problem, annual follow-up is essential.
Management: For treating daytime sleepiness options
include modafinil, methylphenidate, dexamphetamine, selegiline and gammahydroxybutrate. Other co-existing sleep
disorders may also need treatment. For treatment of cataplexy
the options include sodium oxybate, which also treats daytime
sleepiness, tricyclics, SSRIs venlafaxine or gammahydroxybutrate for patients resistant to other medications.
ICGP LIBRARY
& information service
Some suggestions for additional resources:
GUIDELINES
Irish Sleep Society 2007
http://irishsleepsociety.org/iss_guidelines.htm
American Medical Directors Association (2006)
http://www.guideline.gov/summary/pdf.aspx?doc_id=9381&stat=1&string=
GENERAL
US MedlinePlus Information and Tutorial
http://www.nlm.nih.gov/medlineplus/sleepdisorders.html
http://www.nlm.nih.gov/medlineplus/tutorials/sleepdisorders/htm/index.htm
ARTICLES
Australian Family Physician – May 2009 issue dedicated to sleep
http://www.racgp.org.au/afp/200905
ORGANISATIONS listed below provide some interesting
material including a Lark/Owl questionnaire
UK (Sleep Research Centre)
REM sleep behaviour disorder (RBD)
People with RBD lose the muscle atonia that usually
characterises REM sleep. This leads to the acting out of
dream sequences and in some cases violent movements
or actions will result in injury to either the patient or their
bed partner. The age of onset is usually after 60 years and
the condition seems much more common in men, although
this may be biased by the greater potential for injury to
others from men with RBD. RBD can be idiopathic, but
it is particularly associated with Parkinson’s disease and
related conditions such as dementia with Lewy bodies or
Parkinson’s plus syndromes. The frequency in Parkinson’s
disease has been as high as 50% in some series.13 Also,
development of RBD may precede the onset of parkinsonism, even by several years.
Management: Reassurance of the nature of the condition, provision of a safe sleep environment, with removal
of potentially dangerous objects from the bedroom, and
education of the patient and the bed partner are often sufficient in RBD.
Medications that may worsen the condition such as SSRIs
and tricyclic antidepressants should be discontinued if
possible. When drug treatment is warranted, clonazepam
starting at 0.5mg at night seems the most effective intervention, although side-effects are relatively common.
http://www.lboro.ac.uk/departments/ssehs/research/centres-institutes/sleep/
European Society
http://www.esrs.eu/cms/front_content.php
Scotland (Department of Sleep Medicine)
http://www.sleep.scot.nhs.uk/
Claire Dalton is a senior house officer and Shaun O’Keeffe
is consultant geriatrician at the Department of Geriatric
Medicine, Merlin Park University Hospital, Galway
References on request
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