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ScienceWeek
MEDICAL BIOLOGY: ON CHRONIC DAILY HEADACHES
The following points are made by David W. Dodick (New Engl. J. Med. 2006 354:158):
1) Chronic daily headache refers to the presence of a headache more than 15 days per month for longer than 3 months. Chronic daily headache is not a diagnosis but a category that contains many disorders representing primary and secondary headaches.[1,2] Secondary causes must be ruled out before the diagnosis of a primary headache disorder is made. Approximately 3 to 5 percent of the population worldwide[3-5] and 70 to 80 percent of patients presenting to headache clinics in the United States have daily or near-daily headaches. The disability associated with this disorder is substantial and includes a diminished quality of life related to physical and mental health, as well as impaired physical, social, and occupational functioning.
2) Risk factors for chronic daily headache as identified in population-based and clinic-based studies include obesity, a history of frequent headache (more than one per week), caffeine consumption, and overuse (more than 10 days per month) of acute-headache medications, including analgesics, ergots, and triptans. Over half of all patients with chronic daily headache have sleep disturbances and mood disorders such as depression or anxiety, and these disorders can exacerbate the underlying headache.
3) Before a primary headache can be diagnosed, secondary causes must be considered. The development of progressively frequent and severe headaches within a period of three months, neurologic symptoms, focal or lateralizing neurologic signs, papilledema, headaches aggravated or relieved by assuming an upright or supine posture, headaches provoked by a Valsalva maneuver such as a cough or sneeze, systemic symptoms or fever, or a history of headache of sudden onset or onset after the age of 50 years should prompt a diagnostic evaluation with appropriate imaging.
4) Most patients with transformed migraine and medication-overuse headache are women and have a history of episodic migraine that dates back to adolescence or early adulthood. Patients often report a period of transformation that occurs over months or years in which headaches become more frequent, until a pattern of daily or near-daily headaches develops that clinically resembles a mixture of tension-type headache and migraine. This clinical phenotype explains why labels such as "mixed headache" and "tension vascular headache" have been informally applied to this group of patients.
References (abridged):
1. Silberstein SD, Lipton RB, Sliwinski M. Classification of daily and near-daily headaches: field trial of revised IHS criteria. Neurology 1996;47:871-875
2. Headache Classification Subcommittee of the International Headache Society. The international classification of headache disorders, 2nd edition. Cephalalgia 2004;24:Suppl 1:1-160
3. Scher AI, Stewart WF, Liberman J, Lipton RB. Prevalence of frequent headache in a population sample. Headache 1998;38:497-506
4. Castillo J, Munoz J, Guitera V, Pascual J. Epidemiology of chronic daily headache in the general population. Headache 1999;39:190-196
5. Lanteri-Minet M, Auray JP, El Hasnaoui A. Prevalence and description of chronic daily headache in the general population of France. Pain 2003;102:143-149
New Engl. J. Med. http://www.nejm.org
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Related Material:
MEDICAL BIOLOGY: MIGRAINE AND SUBCLINICAL BRAIN LESIONS
The following points are made by M.C. Kruit et al (J. Am. Med. Assoc. 2004 291:427):
1) Migraine is a common, chronic, multifactorial neurovascular disorder typically characterized by recurrent attacks of disabling headache and autonomic nervous system dysfunction (migraine without aura); up to one third of patients also have neurological aura symptoms (migraine with aura).(1-2) Migraine has been suggested to be an independent risk factor for stroke, but the evidence is conflicting and seems to be restricted to certain subpopulations (eg, women with migraine with aura who are younger than 45 years, particularly ones who smoke or use oral contraceptives [OCs]).(3-5) Case reports on patients with so-called migrainous infarction suggest that the posterior circulation territory (PCT) is most commonly affected. However, data are lacking on prevalence of subclinical infarcts in a wide spectrum of migraine patients in the general population.
2) Patients with migraine may also be at increased risk of more diffuse subclinical lesions in the deep white matter or periventricular areas that are only detected on neuroimaging. Several clinic-based magnetic resonance imaging (MRI) studies have reported this, but cardiovascular risk factors and use of vasoconstrictor (migraine) agents, which may also be associated with these lesions, were not always accounted for. As with brain infarction, there are no data on the prevalence of these lesions in patients with migraine from the general population.
3) In view of the high prevalence of migraine, it is important to establish whether migraine is an independent risk factor for subclinical infarcts and white matter lesions (WMLs). Both types of brain lesions have been shown to increase the risk of adverse sequelae, including clinical stroke events, physical limitations, and cognitive impairment, including dementia.
4) The authors report a study to compare the prevalence of brain infarcts and white matter lesions (WMLs) in migraine cases and controls from the general population and to identify migraine characteristics associated with these lesions. The study was a cross-sectional prevalence study of a population-based sample of Dutch adults aged 30 to 60 years. Brain magnetic resonance images were evaluated for infarcts, by location and vascular supply territory, and for periventricular WMLs and deep WMLs.
5) The authors conclude: "These population-based findings suggest that some patients with migraine with and without aura are at increased risk for subclinical lesions in certain brain areas."
References (abridged):
1. Headache Classification Committee of the International Headache Society.. Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Cephalalgia. 1988;8(suppl 7):1-96
2. Ferrari MD. Migraine. Lancet. 1998;351:1043-1051
3. Tzourio C, Tehindrazanarivelo A, Iglesias S, et al. Case-control study of migraine and risk of ischaemic stroke in young women. BMJ. 1995;310:830-833
4. Carolei A, Marini C, De Matteis G, The Italian National Research Council Study Group on Stroke in the Young. History of migraine and risk of cerebral ischemia in young adults. Lancet. 1996;347:1503-1506
5. Chang CL, Donaghy M, Poulter N. Migraine and stroke in young women: case-control study: the World Health Organization Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception. BMJ. 1999;318:13-18
J. Am. Med. Assoc. http://www.jama.com
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Related Material:
ON MIGRAINE
The following points are made by P.J. Goadsby et al (New Engl. J. Med. 2002 346:257):
1) Migraine is a common, chronic, incapacitating neurovascular disorder, characterized by attacks of severe headache, autonomic nervous system dysfunction, and in some patients an aura involving neurological symptoms. Recent advances in basic and applied clinical neuroscience have led to the development of a new class of selective serotonin receptor agonists that activate specific serotonin receptors, these drugs known as "triptans". These agents have changed the lives of countless patients with migraine. But despite such progress, migraine remains underdiagnosed and the available therapies underused.
2) In terms of diagnostic criteria, migraine is defined as episodic attacks of headache lasting 4 to 72 hours; with 2 of the following symptoms: unilateral pain, throbbing, aggravation on movement, pain of moderate or severe intensity; and one of the following symptoms: nausea or vomiting, photophobia or phonophobia.
3) The above symptoms distinguish migraine from tension-type headache, the most common form of primary headache, which is characterized by the lack of associated features. Any severe and recurrent headache is most likely to be a form of migraine and to be responsive to anti-migraine therapy. In 15 percent of patients, migraine attacks are usually preceded or accompanied by transient focal neurological symptoms, which are usually visual; such patients have migraine with aura (previously known as "classic migraine"). In a recent large population-based study, 64 percent of patients with migraine had only migraine without auras, 18 percent had only migraine with aura, 13 percent had both types of migraine, 3 percent had aura without headache. Thus, up to 31 percent of patients with migraine have aura on some occasions, but clinicians who rely on the presence of aura for the diagnosis of migraine will miss some cases.
4) Migraine is best understood as a primary disorder of the brain. It is a form of neurovascular headache: a disorder in which neural events result in the dilation of blood vessels, which in turn results in pain and further nerve activation. Migraine is not caused by a primary vascular event, and migraine attacks are episodic and vary within and among patients. The basic biological problem in migraine is apparently the dysfunction of an ion channel in the aminergic brain stem nuclei that normally modulate sensory input and exert neural influences on cranial blood vessels.
New Engl. J. Med. http://www.nejm.org
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