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Overview
One of the most common afflictions
among all people, headache strikes nearly everyone
at some point in life. While many of these painful
episodes are transitory, experts estimate that up
to 90% of all people - as many as 50 million
persons in the United States alone - suffer some
form of recurrent or chronic headache in their
lifetime. Many of these attacks are severe enough
to disrupt daily activities. An estimated 8
million persons a year visit their doctors with
headache complaints, and the cost in terms of lost
productivity, not to mention diminished quality of
life, may be beyond our ability to compute.
Headache Classification
The International Headache Society (IHS) has
developed a detailed sytem to categorize different
types of headache. The initial division focuses on
the three primary forms of headache:
migraine,
tension type headache,
and cluster headache.
These are then subdivided within each group,
because headaches can vary in presentation
significantly from one individual to another. The
IHS then attempted to describe other forms of
headache that may have an identifiable etiology
and that are different from the three primary
headache types. These include headache associated
with cerebrovascular disease, head trauma,
infection, tumors, medications, and metabolic
abnormalities(e.g., diabetes, thyroid conditions,
hormonal changes). In addition, there are
syndromes that can result in head pain involving
other structures of the head, face, and neck.
These may include pain in the eyes, ears, neck,
teeth, or sinuses.
Causes
While there are several different
types of headache, each of which may vary in
severity, frequency, cause, and symptoms, many
experts generally classify them as primary or
secondary.
Primary headaches are those not
associated with an underlying medical condition.
They account for about 90% of all headaches, of
which the three most common are migraines,
cluster, and tension-type headaches.
Some primary headaches have known
causes, such as stress, muscular tension, vascular
dilation, postural changes, protracted coughing or
sneezing, and fevers. Others, such as migraines,
seem to be triggered by factors varying from diet
to the menstrual cycle to exposure to sunlight.
How these triggers produce pain is still not well
understood.
Secondary headaches are those
associated with an underlying medical condition,
such as infection, injury to the head, and
increased pressure within the skull caused by a
tumor.
Anatomy: Where does the pain come
from?
Headache pain may be confined to a single area or
may be felt in multiple areas of the head, face,
mouth, throat, and neck. In all cases, however,
headache pain derives from the network of nerve
fibers in the tissues, muscles, and blood vessels
located in the head and at the base of the brain.
Interestingly, brain tissue itself has no nerve
fibers and consequently is impervious to pain.
When stimulated by stress, tension,
and other factors, the ends of these nerve fibers,
or nociceptors, generate electrochemical signals
that travel up the nerve network to the brain,
where they are interpreted as pain in the point of
origin. Some of these neurological signals include
natural painkilling compounds called endorphins.
Some researchers believe that people who
experience different types of severe or chronic
pain, including frequent or profound headaches,
may suffer from a lower-than-normal level of
endorphins in their body.
Symptoms
Headache symptoms vary considerably
from person to person, and from one type of
headache to another. A migraine, for example,
produces typically unilateral, throbbing pain that
can last for days, along with an assortment of
secondary symptoms such as nausea, vomiting,
flu-like fever, chills and aches, and others.
Cluster headaches, by comparison, usually occur on
one side of the head only and typically last from
a few minutes to a few hours.
Diagnosis
A thorough medical examination and
history are necessary in the diagnostic evaluation
of the patient complaining of severe headache.
This should include an eye exam to check for
muscular weakness or pupils of unequal size,
detailed questions about the characteristics of
the patient's headache, his or her age, sleep
habits, family history, and a record of
medications being taken.
A neurological examination and
laboratory workup of the patient's blood
characteristics and thyroid, liver, and kidney
functions also may be recommended. In some cases,
imaging studies of the brain may be performed to
rule out brain tumors, stroke, infections,
vascular malformations such as aneurysms, and
other disorders. Such studies may include:
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an EEG (electroencephalogram) to
measure brain activity;
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a CAT (computer axial tomography)
or MRI (magnetic resonance imaging) scan to
examine the tissues and structures around, on,
and in the brain; or
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head x-rays, an MRA (magnetic
resonance angiography) to check the brain's
blood vessels.
Treatment
Many people obtain headache relief
through medication. These treatments can be
divided into two broad categories. Symptomatic
medication is taken at the time of the headache to
treat the symptoms, and prophylactic medication is
taken on a daily basis to prevent headaches from
occurring.
With all analgesic (painkilling)
medications, it is important to guard against
overuse. Excessive consumption of analgesics can
result in drug rebound headache, a condition in
which high levels of the drug in the patient's
system actually cause daily headaches. In most
cases, patients with rebound headaches,
particularly those taking medication on a
prophylactic basis, experience improvement when
their daily medications are stopped, enabling them
to obtain greater relief through symptomatic
treatment.
Not all headaches require medical
treatment. Those resulting from periodic tension
or poor eating habits usually can be dealt with
successfully through lifestyle adjustments and
occasional symptomatic treatment.
Some headaches indicate a more
serious underlying condition requiring prompt
attention, however. Generally, these secondary
headaches are severe, sudden, and debilitating. If
they have been precipitated by a blow to the head,
if they interfere with normal living, or if they
are accompanied by other symptoms - convulsions,
disorientation, dizziness, loss of consciousness,
pain in the eye or ear, or fever - especially in
children or persons who previously were relatively
headache-free, patients should see their family
physician for a medical examination and evaluation
as soon as possible. |
