What are headaches? |

Causes and Symptoms

The International Headache Society has developed the current classification system
for headaches. This system includes fourteen exhaustive categories of headache
with the purpose of developing comparability in the treatment and study of
headaches. Headaches most commonly seen by health care providers can be classified
into four main types: migraine, tension-type, cluster, and other primary
headaches.

Migraine
headaches have an estimated lifetime prevalence of 18
percent, according to the International Association for the Study of Pain.
Migraine headaches are more common in women, and they tend to run in families;
they are usually first noticed in adolescence or young adulthood. For the
diagnosis of migraine without aura (formerly called common migraine or hemicrania
simplex), the person must experience at least five headache attacks, each lasting
between four and seventy-two hours with at least two of the following
characteristics: The headache is unilateral (occurs on one side), has a pulsating
quality, is moderate to severe in intensity, or is aggravated by routine physical
activity. Additionally, one of the following symptoms must accompany the headache:
nausea and/or vomiting or sensitivity to light or sounds. The person’s medical
history, a physical examination, and (where appropriate) diagnostic tests must
exclude other organic causes of the headache, such as brain tumor
or infection such as meningitis. Migraine with aura is far
less common. Migraine with aura (formerly called classical migraine) refers to a
migraine headache with visual disturbances such as the appearance of flickering
lights, spots, or lines and/or the loss of vision; sensory disturbances such as
numbness and/or tingling; and impairment of speech—symptoms that gradually develop
over five to twenty minutes and that last for less than an hour. There are several
subtypes of migraines with aura, including typical aura with migraine headache,
typical aura with nonmigraine headache, typical aura without headache, familial
hemiplegic migraine (migraine with aura including motor weakness in a patient with
a first- or second-degree relative with hemiplegic migraine), sporadic hemiplegic
migraine (migraine with aura including motor weakness in a patient with no first-
or second-degree relatives with hemiplegic migraine), and basilar-type migraine
(migraine with brain-stem aura).

Migraines may be triggered or aggravated by physical activity; by menstruation;
by relaxation after emotional stress; by the ingestion of tyramine in cheddar
cheese or wine, of chocolate, of monosodium glutamate, of sodium nitrate in
processed meats, of nitrites in red wine, and of aspartame; by prescription
medications (including birth control pills and hypertension medications); and by
changes in the weather. Yet the precise pathophysiology of migraines is unknown.
Reduced blood volume in the brain is characteristic of migraine with aura, while
the pathogenesis of migraine without aura is uncertain.

Tension-type headache is the most common type of headache; its mean lifetime
prevalence is approximately 46 percent globally. Tension-type headaches are not
hereditary, occur slightly more frequently in women than in men, and have a mean
age of onset of twenty-five to thirty years, although they can appear at any time
of life. For the diagnosis of tension-type headaches, the person must experience
at least ten headache attacks lasting from thirty minutes to seven days each, with
at least two of the following characteristics: The headache has a pressing or
tightening (nonpulsating) quality, is mild or moderate in intensity (may inhibit
but does not prohibit activities), is bilateral in location, and is not aggravated
by routine physical activity. Additionally, nausea, vomiting, and light or sound
sensitivity are absent or mild. Tension-type headaches have been divided into
episodic and chronic subtypes, and the episodic subtype has been further divided
into frequent and infrequent subtypes. Tension-type headache sufferers describe
these headaches as a band-like or cap-like tightness around the head, and/or
muscle tension in the back of the head, neck, or shoulders. The pain is described
as slow in onset with a dull or steady aching.

Tension-type headaches are believed to be precipitated primarily by psychogenic
factors but can also be stimulated by muscular and spinal disorders, jaw
dysfunction, paranasal sinus disease, and traumatic head
injuries. The pathophysiology of tension-type headaches is
controversial. Tension-type headaches have been attributed to the fascia of the
head, neck, and shoulder muscles causing myogenic-referred pain and to peripheral
pain mechanisms, particularly in episodic tension-type headaches.

Cluster
headaches are the least frequent of the headache types and
are thought to be the most severe and painful. Cluster headaches are more common
in men, with an estimated prevalence of less than 1 percent in the general
population. Typically, these headaches first appear between ten and thirty years
of age, although they can start later in life. Likely risk factors include a
family history of cluster headaches, and possible risk factors include a history
of tobacco smoking or head trauma. For the diagnosis of cluster headaches, the
person must experience at least five severely painful headache attacks with
strictly unilateral pain lasting from fifteen minutes to three hours. One of the
following symptoms must accompany the headache on the painful side of the face: a
bloodshot eye, lacrimation, nasal congestion, nasal discharge, forehead and facial
sweating, contraction of the pupil, or a drooping eyelid. Physical and
neurological examination and imaging must exclude organic causes for the
headaches, such as tumor or infection. Cluster headaches often occur once or twice
daily, or every other day, but can be as frequent as eight attacks in one day,
recurring on the same side of the head during the cluster period. The temporal
“clusters” of these headaches give them their descriptive name.

A cluster headache is described as a severe, excruciating, piercing, sharp, and
burning pain through the eye. The pain is occasionally throbbing but always
unilateral. Radiation of the pain to the teeth has been reported. Cluster headache
sufferers are often unable to sit or lie still and are in such pain that they have
been known, in desperation, to hit their heads with their fists or to smash their
heads against walls or floors.

Cluster headaches can be triggered in susceptible patients by alcohol, histamine,
or nitroglycerine. Because these agents all cause the dilation of blood vessels,
these attacks are believed to be associated with dilation of the temporal and
ophthalmic arteries and other extracranial vessels. There is no evidence that
intracranial blood flow is involved. Cluster headaches have been shown to occur
more frequently during the weeks before and after the longest and shortest days of
the year, lending support for the hypothesis of a link to seasonal changes.
Additionally, cluster headaches often occur at about the same time of day in a
given sufferer, suggesting a relationship to the circadian
rhythms of the body. Vascular changes, hormonal changes,
neurochemical excesses or deficits, histamine levels, and autonomic nervous system
changes are all being studied for their possible role in the pathophysiology of
cluster headaches.

Other primary headaches, using the International Headache Society’s classification
scheme, constitute many of the headaches not mentioned above, including stabbing
headache (occurs spontaneously in the absence of organic disease), cough headache
(brought on by and occurring only in association with coughing or straining),
exertional headache (brought on by and occurring only during or after physical
exertion), headache associated with sexual activity (brought on by and occurring
only as sexual excitement increases), hypnic headache (dull headaches that awaken
the patient from sleep), and thunderclap headache (extremely painful headache with
an abrupt onset).

Distinct from the primary headache types, which are often considered to be chronic
in nature, secondary headaches signify an underlying disease or other medical
condition. Secondary headaches can display pain distribution and quality similar
to those seen in primary headaches. Secondary headaches of concern are usually the
first or worst headache the patient has had or are headaches with recent onset
that are persistent or recurrent. Secondary headaches typically occur for the
first time in close temporal relation to another disorder that causes headaches.
Other signs that cause a high index of suspicion include an unremitting headache
that steadily increases without relief, accompanying weakness or numbness in the
hands or feet, an atypical change in the quality or intensity of the headache,
headache upon recent head trauma or a family history of cardiovascular problems or
cancer. Such headaches can point to hemorrhage, infection such as meningitis,
stroke, tumor, brain abscess, drug withdrawal, and hematoma, which are serious and
potentially life-threatening conditions. A thorough evaluation is necessary for
all patients exhibiting the danger signs of secondary headache.

Treatment and Therapy

Because there are several hundred causes of headaches, the evaluation of headache
complaints is crucial. Medical science offers myriad evaluation techniques for
headaches. The initial evaluation includes a complete history and physical
examination to determine the factors involved in the headache complaint, such as
the general physical condition of the patient, neurological functioning,
cardiovascular condition, metabolic status, and psychiatric condition. Based on
this initial evaluation, the health care professional may elect to perform a
number of diagnostic tests to confirm or reject a diagnosis. These tests might
include blood studies, x-rays, computed tomography (CT) scans,
psychological evaluation, electroencephalograms (EEGs),
magnetic
resonance imaging (MRI), or studies of spinal fluid.

Once a headache diagnosis is made, a treatment plan is developed. In the case of
secondary headaches, treatment may take varying forms depending on the underlying
cause, from surgery to the use of prescription medications. For migraine,
tension-type, and cluster headaches, there are several common treatment options.
Headache treatment can be categorized into two types: abortive (symptomatic)
treatment or prophylactic (preventive) treatment. Treatment is tailored to the
type of headache and the type of patient.

A headache is often a highly distressing occurrence for patients, sometimes
causing a high level of anxiety, relief-seeking behavior, lost productivity, and
reduced quality of life. The health care provider must consider not only
biological elements of the illness but also possible resultant psychological and
sociological elements as well. An open, communicative relationship with the
patient is paramount, and treatment routinely begins with soliciting patient
collaboration and providing patient education. Patient education takes the form of
normalizing the headache experience for patients, thereby reducing their fears
concerning the etiology of the headache or about being unable to cope with the
pain. Supportiveness, understanding, and collaboration are all necessary
components of any headache treatment.

There are a number of abortive pharmacological treatments for migraine headaches.
Ergotamine tartrate (an alkaloid or salt) is effective in terminating migraine
symptoms by either reducing the dilation of extracranial arteries or in some way
stimulating certain parts of the brain. Isometheptene, another effective treatment
for migraine, is a combination of chemicals that stimulates the sympathetic
nervous system, provides analgesia, and is mildly tranquilizing. Another class of
medications for migraines are nonsteroidal anti-inflammatory drugs (NSAIDs); these
drugs, as the name implies, reduce inflammation. Both narcotic and nonnarcotic
pain medications are often used for migraines, primarily for their analgesic
properties, particularly acetaminophen. Antiemetic medications prevent or arrest
vomiting and have been used in the treatment of migraines. Sumatriptan, a
vasoactive agent that increases the amount of the neurochemical serotonin in the
brain, shows promise in treating migraines that do not respond to other
treatments.

There are several nonpharmacological treatment options for migraine headaches.
These include stress management, relaxation training, biofeedback
(a variant of relaxation training), psychotherapy (both individual and family),
and the modification of headache-precipitating factors (such as avoiding certain
dietary precipitants). Each of these treatments has been found to be effective for
certain patients, particularly those with chronic migraine complaints. For some
patients, they can be as effective as pharmacological treatments. The exact
mechanism of action for their effect on migraines has not been established. Other
self-management techniques include lying quietly in a dark room, applying pressure
to the side of the head or face on which the pain is experienced, and applying
cold compresses to the head.

The abortive treatment options for tension-type headaches include narcotic and
nonnarcotic analgesics because of their pain-reducing properties. More often with
tension-type headaches, the milder over-the-counter pain medications (such as
aspirin or acetaminophen) are used. NSAIDs are a first-line treatment for
tension-type headaches.

Prophylactic treatments for tension-type headaches include tricyclic
antidepressants. Acupuncture and physical therapy may also be options to
treat frequent tension-type headaches. Physical therapy options include massage,
exercise, treatments to improve posture, and hot and cold packs. Electromyography
(EMG) biofeedback has also shown to have benefits in the treatment of tension-type
headaches. The identification and avoidance of possible tension-type headache
triggers, such as stress, irregular or inappropriate meals, high intake or
withdrawal of caffeine, dehydration, inadequate sleep, or
inappropriate sleep, may also be beneficial.

For cluster headaches, one of the most excruciating types of headache, the most
common abortive treatment is administering pure oxygen to the patient for ten
minutes. The exact mechanism of action is unknown, but it might be related to the
constriction of dilated cerebral arteries. Other first-line treatments include a
subcutaneous injection of sumatriptan and an intranasal spray containing
zolmitriptan. Ergotamine tartrate or similar alkaloids can also abort the attack
in some patients. Nasal drops of a local anesthetic (lidocaine hydrochloride) have
been used to ease cluster headaches. The efficacy of these treatments is
inconclusive.

Prophylactic treatment of this headache type is crucial. Verapamil is often given
in addition to abortive treatments and then withdrawn at the end of a cluster
episode. Lithium may be considered as a second-line medication if verapamil is
ineffective. Melatonin, corticosteroids, and dihydroergotamine may also be used
for the prophylactic treatment of cluster headaches.

While no nonpharmacological treatment strategies are routinely offered to cluster
headache patients, surgery is an option in severe cases in which the headaches are
resistant to all other available treatments. Subcutaneous occipital nerve
stimulation via an implant has been reported to improve chronic cluster headaches.
Sphenopalatine ganglion stimulation via an implant may reduce the frequency and
intensity of cluster headache attacks. Modest successes have been found with these
extreme treatment options.

Perspective and Prospects

Headaches are among the most common complaints to physicians and quite likely have
been a problem since the beginning of humankind. Accounts of headaches can be
found in the clinical notes of Arateus of Cappadocia, a first-century physician.
Descriptions of specific headache subtypes can be traced to the second century in
the writings of the Greek physician Galen. Headaches are prevalent health
problems that affect all ages and sexes and those from various cultural, social,
and educational backgrounds.

The prevalence of headaches is greater in women, although the reason is unknown.
Age seems to be a mediating factor as well, with significantly fewer people over
the age of sixty-five years reporting headache problems. There are no
socioeconomic differences in prevalence rates, with persons in high-income and
low-income brackets having similar rates.

The total economic costs of headaches are staggering. The expenses associated with
advances in assessment techniques and routine health care have risen rapidly. The
cost in lost productivity adds to this economic picture. The scientific study of
headaches is necessary to understand this prevalent illness. Efforts, such as
those by the International Headache Society, to develop accepted definitions of
headaches will greatly assist efforts to identify and treat headaches.

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