C h a p t e r 3 5
Somatosensory Function, Pain, and Headache
875
before prophylactic agents will be effective. Most of the
medications used for prevention of CDH have not been
examined in well-designed, double-blind studies.
Temporomandibular Joint Pain
A common cause of head pain is temporomandibular
joint (TMJ) syndrome. It usually is caused by an imbal-
ance in joint movement because of poor bite, bruxism
(i.e., teeth grinding), or joint problems such as inflam-
mation, trauma, and degenerative changes.
56
The pain
almost always is referred and commonly presents as
facial muscle pain, headache, neck ache, or earache.
Referred pain is aggravated by jaw function. Headache
associated with this syndrome is common in adults and
children and can cause chronic pain problems.
Treatment of TMJ pain is aimed at correcting the prob-
lem, and in some cases this may be difficult. The initial
therapy for TMJ pain should be directed toward relief of
pain and improvement in function. Pain relief often can
be achieved with use of the NSAIDs. Muscle relaxants
may be used when muscle spasm is a problem. In some
cases, the selected application of heat or cold, or both,
may provide relief. Referral to a dentist who is associated
with a team of therapists, such as a psychologist, physical
therapist, or pain specialist, may be indicated.
Pain in Children and Older
Adults
Pain frequently is under-recognized and undertreated in
both children and the elderly. In addition to the concern
about the effects of analgesia on respiratory status and
the potential for addiction to opioids, another obstacle
to adequate pain management in children and the elderly
is the myth that patients in these age groups feel less pain
than other patients, and even if they feel significant pain,
they do not remember it. Moreover, it can be extremely
difficult to accurately assess the location and intensity of
pain in very young children, who are cognitively imma-
ture, or in cognitively impaired elderly. Research during
the past few decades has added a great deal to the body
of knowledge about pain in children and the elderly.
Pain in Children
Human responsiveness to painful stimuli begins in the
neonatal period and continues through the life span.
Although the specific and localized behavioral reactions
are less marked in newborns, they clearly perceive and
remember pain, as demonstrated by their integrated
physiologic responses, including protective or with-
drawal reflexes, to nociceptive stimuli.
57–59
For example,
newborns in the neonatal intensive care unit (NICU)
demonstrate protective withdrawal responses to a heel
stick after repeated episodes. In fact, a newborn’s pain
may be accentuated because descending inhibitory path-
ways to the dorsal horn are not as well developed at
birth.
58
Furthermore, the newborn’s dorsal horn neu-
rons have a wider receptive field and lower excitatory
threshold than those of older children. The recognition
that untreated pain can lead to serious consequences has
resulted in a more liberal use of opioids for treatment of
pain in the newborn, particularly in the NICU.
59
As infants and children mature cognitively and
developmentally, their responses to pain become more
complex. Children do feel pain and have been shown
to reliably and accurately report pain at as young as 3
years of age.
59
Like newborns, they also remember pain,
as evidenced in studies of children with cancer, whose
distress during painful procedures increases over time
without intervention.
Pain Assessment
To manage pain adequately, ongoing assessment of the
presence of pain and response to treatment is essen-
tial.
58,59
Behavior is a useful sign, but can be mislead-
ing. A toddler may scream during an ear examination
because of fear rather than pain, and a child with inad-
equately relieved cancer pain may withdraw from his
or her surroundings. Some physiologic measures, such
as heart rate, are convenient to measure and respond
rapidly to brief nociceptive stimuli, but they are nonspe-
cific. Investigators have devised a range of behavioral
distress scales for infants and young children, mostly
emphasizing the child’s facial expressions, crying, and
bodily movements.
Children 3 to 7 years of age become more articu-
late in describing the intensity, location, and severity of
the pain. There are self-report measures for children of
this age, including scales with faces of actual children
or cartoon faces. With children 8 years of age or older,
SUMMARY CONCEPTS
■■
Headache is a common disorder that is caused
by a number of conditions. Some headaches
represent primary disorders and others occur
secondary to another disease state in which head
pain is a symptom.
■■
Primary headache disorders include migraine
headache, tension-type headache, cluster
headache, and chronic daily headache.
■■
Although most causes of secondary headache are
benign, some are indications of serious disorders
such as meningitis, brain tumor, or ruptured
cerebral aneurysm.
■■
Temporomandibular joint (TMJ) syndrome is one of
the major causes of headaches. It usually is caused
by an imbalance in joint movement because of
poor bite, teeth grinding, or joint problems such as
inflammation, trauma, and degenerative changes.
