874
U N I T 1 0
Nervous System
prolonged aura, or migrainous infarction.
48
In most
cases, preventative treatment must be taken daily for
months to years. First-line agents include
β
-adrenergic
blocking medications (e.g., propranolol, atenolol), anti-
depressants (amitriptyline), and antiseizure medications
(e.g., divalproex, valproic acid). When a decision to dis-
continue preventive therapy is made, the medications
should be gradually withdrawn.
Cluster Headache
Cluster headaches are relatively uncommon headaches
that occur in about 1 in 1000 individuals, affecting men
(80% to 85%) more frequently than women with the
typical age of onset between 20 to 40 years of age.
50
These headaches tend to occur in clusters over weeks
or months, followed by a long, headache-free remission
period. Cluster headache is a type of primary neuro-
vascular headache that typically includes severe, unre-
lenting, unilateral pain located, in order of decreasing
frequency, in the orbital, retro-orbital, temporal, supra-
orbital, and infraorbital regions.
50–52
The pain is of rapid
onset, builds to a peak in approximately 10 to 15 min-
utes, and lasts for 15 to 180 minutes. The pain behind
the eye radiates to the ipsilateral trigeminal nerve (e.g.,
temple, cheek, gum). The headache frequently is associ-
ated with one or more symptoms such as restlessness or
agitation, conjunctival redness, lacrimation, nasal con-
gestion, rhinorrhea, forehead and facial sweating, mio-
sis, ptosis, and eyelid edema. Because of their location
and associated symptoms, cluster headaches are often
mistaken for sinus infections or dental problems.
The underlying pathophysiologic mechanisms of clus-
ter headaches are not completely known. It is thought
that heredity, through an autosomal dominant gene, plays
some role in the pathogenesis of the headaches. The most
likely pathophysiologic mechanisms include the interplay
of vascular, neurogenic, metabolic, and humoral factors.
The regulating centers in the hypothalamus are thought
to play a role because of circadian biologic changes and
neuroendocrine disturbances (e.g., changes in cortisol,
prolactin, and testosterone) that are observed both in
active periods and during clinical remission.
Because of the relatively short duration and self-
limited nature of cluster headache, oral preparations
typically take too long to reach therapeutic levels. The
most effective treatments are those that act quickly
(e.g., oxygen inhalation and subcutaneous sumatriptan).
Intranasal lidocaine also may be effective.
51,52
Oxygen
inhalation may be indicated for home use. Prophylactic
medications for cluster headaches include ergotamine
derivatives, verapamil (a calcium channel blocker), corti-
costeroids, and valproic acid. Deep-brain surgical neuro-
stimulation is an experimental approach beginning to
show promise in the elimination of cluster headaches.
51
Tension-Type Headache
The most common type of headache is tension-type head-
ache. Unlike migraine and cluster headaches, tension-type
headache usually is not sufficiently severe that it interferes
with daily activities. Tension-type headaches frequently
are described as dull, aching, diffuse, nondescript head-
aches, occurring in a hatband distribution around the
head, and not associated with nausea or vomiting or
worsened by activity. They can be infrequent, episodic,
or chronic.
The exact mechanisms of tension-type headache are
not known and the hypotheses of causation are con-
tradictory. One popular theory is that it results from
sustained tension of the muscles of the scalp and neck.
Another theory suggests that migraine headache may be
transformed gradually into chronic tension-type head-
ache. Oromandibular dysfunction, psychogenic stress,
anxiety, and depression may contribute, and overuse of
analgesics or caffeine may also be involved.
53
Tension-type headaches often are more responsive to
nonpharmacologic techniques, such as biofeedback, mas-
sage, acupuncture, relaxation, imagery, and physical ther-
apy, than other types of headache. For persons with poor
posture, a combination of range-of-motion exercises,
relaxation, and posture improvement may be helpful.
The medications of choice for acute treatment of ten-
sion-type headaches are analgesics, including acetylsali-
cylic acid, NSAIDs, and acetaminophen.
53
Persons with
infrequent tension-type headache usually self-medicate
using over-the-counter analgesics to treat the acute pain,
and do not require prophylactic medication. These agents
should be used cautiously because rebound headaches
can develop when the medications are taken regularly.
Other medications, including the entire range of migraine
medications, may be tried in refractory cases.
Chronic Daily Headache
The term
chronic daily headache
(CDH) is used to refer
to headaches that occur 15 days or more a month,
including those due to medication overuse.
54,55
Little
is known about the prevalence and incidence of CDH.
Diagnostic criteria for CDH are not provided in the IHS
Classification System. The cause of CDH is unknown,
although there are several hypotheses. They include
transformed migraine headache, evolved tension-type
headache, new daily persistent headache, and post-
traumatic headache. In many persons, CDH retains
certain characteristics of migraine, whereas in others
it resembles chronic tension-type headache. Chronic
daily headache may be associated with chronic and
episodic tension-type headache. New daily persistent
headache may have a fairly rapid onset, with no history
of migraine, tension-type headache, trauma, or psycho-
logical stress. Although overuse of symptomatic medi-
cations (e.g., analgesics, ergotamine) has been related
to CDH, there is a group of patients in whom CDH is
unrelated to excessive use of medications.
For patients with CDH, a combination of pharma-
cologic and behavioral interventions may be necessary.
As with tension-type headaches, nonpharmacologic
techniques, such as biofeedback, massage, acupunc-
ture, relaxation, imagery, and physical therapy, may
be helpful. Measures to reduce or eliminate medica-
tion and caffeine overuse may be helpful. If the patient
is abusing medications, the overuse must be managed
