Medical Chronicle November/December 2013 | Page 34

PAIN

Pain and insomnia
PROF CM SCHUTTE Head: Department of Neurology, University of Pretoria
Worldwide, both chronic pain and
insomnia are recognised as major
health issues. It appears logical that
people who are in pain cannot sleep,
but sleep deprivation and insomnia
may cause physical discomfort and
reduced pain thresholds. Research has
shown that common neurobiological
systems are involved in both the
modulation of pain and the regulation
of the sleep-wake states.
This can relate to important criteria
such as a difficulty in initiating
and/or maintaining sleep, as well
as non-restorative, non-refreshing
sleep, which causes some form of
daytime impairment (such as fatigue,
memory impairment, occupational
impairment, sleepiness and
propensity for accidents).
Only about 10%-15% of patients
with insomnia have primary

Insomnia

insomnia; the vast majority have
comorbid insomnia, where other
disorders contribute to the sleep
dysfunction.
In a patient who complains of pain
and insomnia, the first step in the
evaluation is to eliminate any other
sleep disorder as a primary disorder.
To eliminate a possible diagnosis of
obstructive sleep apnoea syndrome,
information about heavy snoring
and/or cessation of breathing during
the night should be obtained. For
a diagnosis of possible restless
legs syndrome and periodic limb
movements in sleep, the patient
should be asked about twitching legs
and feelings of extreme discomfort in
the legs when resting, or waking up
with the sensation that the legs are
jerking. There are many other sleep
abnormalities that can be important,
but these occur less commonly. If
indicated, the patient should be

34 MEDICAL CHRONICLE NOVEMBER/DECEMBER 2013

referred for a polysomnogram.

Other conditions causing
sleep disorders

Psychiatric conditions such as
anxiety disorders, depression and
substance abuse should be ruled out.
Insomnia may often occur before
other signs of psychiatric illnesses are
present. Neurological disease such as
Parkinson’s disease has been shown
to be associated with REM sleep
disorders. Physical conditions such
as cardiac or pulmonary disorders
should then also be ruled out.

PAIN CAUSING INSOMNIA

Several painful conditions can lead to
insomnia:
In clinical headache populations,
an acute sleep disturbance is often

Headache

recognised as a trigger for a headache.
In a recent study, it was reported that
almost 80% of patients complained of
insomnia prior to a migraine attack.
Sleeping late or oversleeping is also
associated with a headache and many
patients wake up with headache.
Chronic tension-type headaches may
also be associated with insomnia.
Patients with episodic cluster
headaches frequently have complaints
of insomnia. Within a cluster period,
the patient is typically woken up
after 1½-2 hours of sleep onset with
excruciating, usually unilateral
headache. REM sleep may precipitate
a cluster headache attack.
Generally, morning headaches
on awakening or headache waking
the patient from sleep should
always raise the suspicion of sleep
disorder breathing syndromes such
as obstructive sleep apnoea. Lastly,
patients with newly developed