MIDTERM Flashcards
Around 4% of the adult population experiences a level of daytime
sleepiness that could be considered abnormal and potentially
intrusive or even dangerous to routine daily activities.
EXCESSIVE DAYTIME SLEEPINESS
Complaints of drowsiness or an appropriate and excessive
tendency to nap during the day need to be carefully distinguished
from simple:
tiredness
fatigue
Lack of energy
Symptoms of EDS
Poor concentration
motor clumsiness
automatic behaviour
EDS can still be dismissed by many as resulting merely from
poor lifestyle habits
laziness
reduced motivation
These phenomena usually have different etiologies, such as chronic fatigue
syndrome in which there is no objective for an increased tendency to fall asleep.
EXCESSIVE DAYTIME SLEEPINESS
Often mistakenly attributed to reflect mood disorder (depression),
hormonal balance (hypothyroidism) or anemia.
EXCESSIVE DAYTIME SLEEPINESS
formal diagnosis of sleep disorder causing EDS may be delayed in youngsters
who display behavioral problems of irritability or paradoxical hyperactivity rather
than more obvious symptoms of sleepiness
EXCESSIVE DAYTIME SLEEPINESS
Teenager and young adults, in particular, may seek to ‘
“ self-medicate” with
recreational stimulant drugs.
EDS
The potential hazards of EDS when performing monotonous task such as
driving are obvious and often preventable.
EDS
Occupational health physicians are increasingly aware of EDS as an issue both
at work and on the daily commute, especially in shift worker.
EDS
usually a persistent or chronic
symptoms although there are a few rare causes of intermittent sleepiness,
EDS
Primary sleep disorders
with sleep-wake dysregulation
Narcolepsy
*diopathic hypersomnolence
* Klein-Levine syndrome
Circadian misalignment
Shift work sleep
disorder
* Jet lag
* Delayed sleep phase
syndrome
Sleepiness secondary to a
chronic disorder
Obstructive sleep
apnoea/hypopnoea
syndrome
Restless legs syndrome
, Parkinson’s disease
* Depression
* Myotonic dystrophy
Multiple sclerosis
* Pain syndromes
The commonest cause
of mild sleepiness
simply insufficient
nocturnal sleep.
EDS can be broadly
divided into three
categories
Primary sleep disorders
with sleep-wake dysregulation
Sleepiness secondary to a
chronic disorder
Circadian misalignment
most frequently starts in early adolescence and is a lifelong
affliction.
Narcolepsy
This produces a deficiency of a neuropeptide
hypocretin
a key regulator of the sleep-wake cycle.
hypocretin
Has been recognized as a distinct syndrome for well over a century although it
is only in the last decade that its underlying neurobiology has been established
NARCOLEPSY
Genetic analysis of a canine model of narcolepsy le to the surprising discovery
that classical cases of human narcolepsy arise from specific destruction of a few
thousand neurons in the lateral hypothalamus.
NARCOLEPSY
Given its specific neurochemical basis, it is perhaps not surprising that there is a
spectrum of severity such that mild cases often escape medical attention.
NARCOLEPSY
Irresistible sleep episodes, occasionally without recognizing the prior imperative
to sleep, may produce
“sleep attacks”
Naps are typically fairly short and often refreshing.
(around 20 minutes or less)
Specific and diagnostically important symptom in narcolepsy
cataplexy.
Many narcoleptics can sustain wakefulness if engaged in alerting activities but
fight sleep if bored or unoccupied.
NARCOLEPSY
which full awareness is diminished
and automatic behaviors may occur with poor recall
“micro sleeps”
Attacks are generally brief and take a few seconds to build up
Typically with head bobbing or facial jerking at the onset.
This may suggest an epileptic phenomenon although a key feature of
cataplexy is maintained awareness of the environment even when paralyzed
may help to confirm clinical impressions and exclude
other diagnoses.
INVESTIGATIONS
International guidelines have rightly placed great emphasis on the presence of
typical cataplexy which, if present, in the context of EDS is sufficient for a
positive diagnosis.
INVESTIGATIONS
Many authorities, however, would advocate obtaining objective evidence of
sleepiness by ____________
undertaking a multiple latency test (MSLT)
Over four or five nap opportunities at two-hourly intervals, a narcoleptic should
fall asleep, on average, within eight minutes or sooner and enter REM sleep
within 15 minutes in at least two of the naps.
Over four or five nap opportunities at two-hourly intervals, a narcoleptic should
fall asleep, on average, within eight minutes or sooner and enter REM sleep
within 15 minutes in at least two of the naps.
Most narcoleptics benefits from drug medication although planned brief naps
during day or adjustments to diet can improve symptom control in many
Most narcoleptics benefits from drug medication although planned brief naps
during day or adjustments to diet can improve symptom control in many
Caffeinated drinks or caffeine supplements from pharmacies are rarely
sufficient to provide normal alertness but can be a useful supplement.
Caffeinated drinks or caffeine supplements from pharmacies are rarely
sufficient to provide normal alertness but can be a useful supplement.
It should be emphasized that, even with optimal drug treatment, a significant
proportion of patients are never normalized with respect to their sleep-wake
cycle.
It should be emphasized that, even with optimal drug treatment, a significant
proportion of patients are never normalized with respect to their sleep-wake
cycle.
usually the most disabling symptoms and combination of wake-promting
agents typically modafinil and dexamphetamine, may be needed.
EDS
may improve concurrently with increased wakefulness but
approximately 50% of patients benefits from additional medication.
Cataplexy
It is controversial drug, largely due to its commercial expense and fears over
potential misuse recreationally.
It is controversial drug, largely due to its commercial expense and fears over
potential misuse recreationally.
may therefore be justified in certain situations, particularly if
narcoleptic symptoms are atypical.
Brain imaging
With increasing knowledge of sleep neurobiology and the nature of narcolepsy,
it is valid to consider secondary causes especially if there is proven pathology in
the region of the hypothalamus.
SECONDARY NARCOLEPSY
Very occasionally, inflammatory disorders such as multiple sclerosis may be
associated with a form of narcolepsy with lesions seen in or around the
hypothalamus on imaging.
SECONDARY NARCOLEPSY
A variety of structural pathologies in the region of the floor of the third ventricle,
adjacent to the hypothalamus, have also been reported to cause narcoleptic
symptoms.
SECONDARY NARCOLEPSY
In a range of neurological disorders, the level and nature of EDS may mimic
narcolepsy even if the underlying mechanism remains obscure.
SECONDARY NARCOLEPSY
Examples include myotonic dystrophy, Parkinson’s disease, head injury and
certain rare developmental disorders, such as Prader- Willi syndrome
SECONDARY NARCOLEPSY
A rare cause of severe EDS often affecting young populations and potentially
mimicking narcolepsy
IDIOPATHIC HYPERSOMNOLENCE
The underlying neurobiology is not established and subjects simply appear to
need far more sleep than average.
IDIOPATHIC HYPERSOMNOLENCE
In typical cases, despite 10 hours of good quality sleep, there are major
difficulties arising at a conventional hour and a subsequent propensity for
prolonged unrefreshing daytime naps.
IDIOPATHIC HYPERSOMNOLENCE
Unlike narcolepsy, there are few symptoms suggesting abnormal REM sleep or
related phenomena.
IDIOPATHIC HYPERSOMNOLENCE
In some patients the clinical picture appears to lie between IH and narcolepsy.
IDIOPATHIC HYPERSOMNOLENCE
In general wake-promoting treatment tend to be less successful in IH, with
many patients unable to work or study effectively.
IDIOPATHIC HYPERSOMNOLENCE
Frustration and depression are frequent associations.
IDIOPATHIC HYPERSOMNOLENCE
Symptoms typical in IDIOPATHIC HYPERSOMNOLENCE
1Unavoidable daytime naps
2Automatic behaviours common
3Overnight sleep is prolonged
4Morning waking difficult
5Sleep latency is around eight
minutes or less on a multiple
sleep latency test (MSLT)
Mood disorder common
