Page 227 Guide to Pain Management in Low-Resource Settings

Headache 215

headache manifesting in attacks lasting between 4 and disability and reduced quality of life, even between at-
72 hours. Typical features of this headache are unilateral tacks. Although migraine is one of the most common
location, pulsating quality, moderate or severe intensity, reasons for patients to consult their doctor, and despite
aggravation by routine physical activity, and association its enormous impact, it is still under-recognized and
with nausea and/or photophobia and phonophobia (see undertreated. Th is lack of recognition has various rea-
Table 3 for diagnostic criteria of migraine without aura sons. On the one hand, there are no biological markers
from the ICHD-2). to confi rm the diagnosis, and many doctors lack knowl-
Th e headache may be preceded in 15–20% of pa- edge, time, interest, or all three, to manage migraineurs.
tients by an aura, so-called migraine with aura. Th e aura On the other hand, there is no cure for migraine, and,
may last between 5 and 60 minutes. Th e most common although eff ective therapies do exist, they have only par-
type is visual aura, causing scotomas, teichopsia, forti- tial effi ciency or are not accessible to all. Finally, percep-
fi cation spectra, and photopsias. It can also comprise tion of migraine may vary between cultures, some of
other neurological symptoms such as focal paresthe- which tend to negate or trivialize its existence. As a re-
sias, speech disturbances and, in hemiplegic migraine, a sult, a proportion of aff ected individuals do not seek (or
unilateral motor defi cit. Th e heterogeneity of the clini- have given up on) medical help.
cal phenotype of migraine is underestimated. Despite a Migraine is a neurovascular disorder (i.e., both
common diagnostic denominator, some clinical features neuronal and vascular factors are involved) in which ge-
such as type of aura symptoms, pain intensity, presence netic susceptibility renders the brain hyperresponsive to
of prodromes, coexistence of migraine with and without stimuli and probably metabolically vulnerable, setting a
aura, or associated symptoms such as vertigo, may char- “migraine threshold” on which trigger factors may act
acterize subgroups of patients bearing diff erent underly- to precipitate an attack. Th e consensus is now that the
ing pathophysiological and genetic mechanisms. migraine aura is caused by the neuron-glial phenome-
In migraine, premonitory symptoms and trig- non of so-called “cortical spreading depression,” where
ger factors are manyfold, and they may vary between a brief front of neuronal depolarization (“scintillations”)
patients and during the disease course. Th e most is followed by a wave of arrest of neuronal activity due
frequently reported premonitory symptoms are fa- to hyperpolarization; both spread over the cortex with a
tigue, phonophobia, and yawning. Concerning trig- velocity of 3–5 mm/minute.
ger factors, the most common ones are stress, the Th e migraine headache probably results from
perimenstrual period, and alcohol. Overuse of acute activation of the trigeminovascular system, the major
antimigraine drugs, in particular of combination anal- pain-signaling system of the visceral brain composed of
gesics and ergotamine, is another underestimated fac- nociceptive aff erents belonging to the visceral portion of
tor leading to chronifi cation. the ophthalmic nerve (V1) and surrounding meningeal
If the migraine is a benign condition, the se- blood vessels. Th e precise pathogenic relationship be-
verity and frequency of attacks can result in signifi cant tween aura and migraine headache is not fully clarifi ed.

Table 3
Typical symptoms of migraine and tension-type headache
Migraine Tension-Type Headache
Sex ratio (F:M) 2 to 3:1 5:4
Pain
Type Pulsating Pressing/tightening (non-pulsating) quality
Severity Moderate to severe Mild or moderate intensity
Site Unilateral Bilateral
Aggravated by routine physical activity Yes No
Duration of attack 4 to 72 h 30 minutes to 7 days
Autonomic features No No
Nausea and/or vomiting Yes No
Photophobia and/or phonophobia Yes, both No more than one of photophobia or phonophobia