In medicine a
headache or
cephalalgia is a
symptom of a number of different conditions of the
head. Some of the causes are benign while
others are medical emergencies.
There are a number of different classification systems for
headaches. The most well-recognized is that of the
International Headache
Society.
Treatment of a headache depends on the underlying etiology or
cause, but commonly involves
analgesics.
Classification
The first recorded classification system that resembles the modern
ones was published by
Thomas Willis,
in
De Cephalagia in 1672. In 1787
Christian Baur generally divided headaches
into
idiopathic (primary headaches) and
symptomatic (secondary ones), and
defined 84 categories.
Today headaches are most thoroughly classified by the
International Headache
Society's International Classification of Headache Disorders
(ICHD), which published the second edition in 2004. This
classification is accepted by the
WHO.
Other classification systems exist. One of the first published
attempts was in 1951.
The National Institutes of Health
developed a classification system in
1962.
Headaches can also be classified by severity and acuity of onset.
Headaches that are both severe and acute are known as
thunderclap headaches.
ICHD-2
The
International
Classification of Headache Disorders (ICHD) is an in-depth
hierarchical classification of
headaches published by the
International Headache
Society. It contains explicit (operational)
diagnostic criteria for headache
disorders. The first version of the classification, ICHD-1, was
published in 1988. The current revision, ICHD-2, was published in
2004.
The classification uses numeric codes. The top, one-digit
diagnostic level includes 14 headache groups. The first four of
these are classified as primary headaches, groups 5-12 as secondary
headaches,
cranial neuralgia, central and primary facial pain and
other headaches for the last two groups.
NIH
The NIH classification consists of brief definitions of a limited
number of headaches.
Symptoms and signs
Headache associated with specific symptoms may warrant urgent
medical attention, particularly sudden, severe headache or sudden
headache associated with a
stiff
neck; headaches associated with
fever,
convulsions or accompanied by confusion
or
loss of consciousness;
headaches following a blow to the head, or associated with pain in
the eye or ear; persistent headache in a person with no previous
history of headaches; and recurring headache in children.
Pathophysiology
The
brain in itself is not sensitive to
pain, because it lacks
nociceptors. However, several areas of the
head and
neck do have
nociceptors, and can thus sense pain. These include the
extracranial arteries, large veins, cranial and spinal nerves, head
and neck muscles and the
meninges.
Diagnosis
In 2008, the
American College of
Emergency Physicians updated their guidelines on the evaluation
and management of adult patients who have a nontraumatic headache
of acute onset.
While, statistically, headaches are most likely to be primary
(harmless and self-limiting), some specific secondary headache
syndromes may demand specific treatment or may be warning signals
of more serious disorders. Differentiating between primary and
secondary headaches can be difficult.
As it is often difficult for patients to recall the precise details
regarding each headache, it is often useful for the sufferer to
fill-out a "headache diary" detailing the characteristics of the
headache.
Imaging
When the headache does not clearly fit into one of the recognized
primary headache syndromes or when atypical symptoms or signs are
present then further investigations are justified. Neuroimaging
(noncontrast head CT) is recommended if there are new neurological
problems such as decreased level of consciousness, one sided
weakness, pupil size difference, etc or if the pain is of sudden
onset and severe, or if the person is known HIV positive. People
over the age of 50 years may also warrant a CT scan.
Treatment
Acute headaches
Not all headaches require medical attention, and most respond with
simple
analgesia (painkillers) such as
paracetamol/acetaminophen or members of
the
NSAID class
(such as
aspirin/acetylsalicylic acid,
diclofenac or
ibuprofen).
A small 2009 study found that 100% oxygen at 15 l / min was
effective at relieving undifferentiated headache pain in the
emergency department.
Chronic headaches
In recurrent unexplained headaches keeping a "headache
diary" with entries on type of headache, associated
symptoms, precipitating and aggravating factors may be helpful.
This may reveal specific patterns, such as an association with
medication,
menstruation or
absenteeism or with certain foods.It was
reported in March 2007 by two separate teams of researchers that
stimulating the brain with implanted electrodes appears to help
ease the pain of cluster headaches.
Acupuncture has been found to be
beneficial in chronic headaches of both tension type and migraine
type. Whether or not there is a difference between true acupuncture
and sham acupuncture however is yet to be determined.
Epidemiology
During a given year, 90% of people suffer with headaches. Of the
ones who are seen in the
ER,
about 1% have a serious underlying problem.
References
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