Migraine Headache/Migraine is a genetically influenced complex disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea and light and sound sensitivity. This activity reviews the evaluation and treatment of migraines and highlights the role of the interprofessional team in evaluating and treating patients with this condition.
Migraine is a genetically influenced complex disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea and increased sensitivity to light and sound. The word migraine is derived from the Greek word “hemicrania” that later was converted into Latin as “emigrants.” The French translation of such a term is “migraine.”[rx] Migraine is a common cause of disability and loss of work. Migraine attacks are a complex brain event that unfolds over hours to days, in a recurrent matter. The most common type of migraine is without aura (75% of cases).
Types of Migraine Headache
Migraine can be classified in subtypes, according to the headache classification committee of the International Headache Society:[rx]
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Migraine without aura is a recurrent headache attack of 4 to 72 hours; typically unilateral in location, pulsating in quality, moderate to severe in intensity, aggravated by physical activity, and associated with nausea and light and sound sensitivity (photophobia and phonophobia).
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Migraine with aura has recurrent fully reversible attacks, lasting minutes, of typically one or more of these unilateral symptoms: visual, sensory, speech and language, motor, brainstem, and retinal, usually followed by headache and migraine symptoms.
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Chronic migraine is a headache that occurs on 15 or more days in a month for more than three months and has migraine features on at least eight or more days in a month.
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Complications of migraine
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Status migrainosus is a debilitating migraine attack that lasts more than 72 hours.
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Persistent aura without infarction is an aura that persists for more than one week without evidence of infarction on neuroimaging.
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Migrainous infarction is one or more aura symptoms associated with brain ischemia on neuroimaging during a typical migraine attack
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Migraine aura-triggered seizure occurs during an attack of migraine with aura, and a seizure is triggered
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Probable migraine is an asymptomatic migraine attack that lacks one of the features required to fulfill criteria for one of the above and does not meet the criteria for another type of headache.
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Episodic syndromes that may be associated with migraine
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Recurrent gastrointestinal disturbances are recurrent attacks of abdominal pain and discomfort, nausea and vomiting, that may be associated with migraines.
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Benign paroxysmal vertigo has brief recurrent attacks of vertigo.
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Benign paroxysmal torticollis is recurrent episodes of head tilt to one side.
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Causes of Migraine Headache
Genetics and Inheritance
Migraine has a strong genetic component. The risk of migraines in ill relatives is three times greater than that of relatives of non-ill subjects, but there has not been any pattern of inheritance identified.[rx][rx] The genetic basis of migraine is complex, and it is uncertain which loci and genes are the ones implicated in the pathogenesis; it may be based on more than one genetic source at different genomic locations acting in tandem with environmental factors to bring susceptibility and the characteristics of the disease in such individuals.[rx] The identification of these genes in an individual with migraines could predict the targeted prophylactic treatment.
Familial Hemiplegic Migraine
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Hemiplegic migraine can occur in families or sporadically (one individual, as the first member of the family to have a hemiplegic migraine).[rx] Channelopathies cause the primary three types:
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Type 1 is caused by mutations in the CACNA1A gene (calcium voltage-gated channel alpha 1A subunit) on chromosome 19p13.[rx]
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Type 2 is caused by mutations in the ATP1A2 gene (ATPase, Na+/K+ transporting alpha 2 subunit) on chromosome 1q23.[rx]
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Type 3 is caused by mutations in the SCN1A gene (sodium voltage-gated channel Type 1 alpha subunit).
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Mutations in the SLC4A4 (solute carrier family 4 member 4) gene have also been associated with familial forms of migraine.[rx]
MELAS – Melas is a syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes a multisystemic disorder by maternal inheritance that can present recurrent migraine headaches.[rx]
CADASIL – Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) angiopathy by autosomal dominant inheritance, caused by mutations in the NOTCH3 gene (notch receptor 3) on chromosome 19, that can present migraine with aura (prodrome in 80%) in nearly 50% of carriers.[rx]
RVCL – Retinal vasculopathy with cerebral leukodystrophy is angiopathy by C-terminal frame-shift mutations in TREX1 (three prime repair exonuclease 1) presents almost 60% of the cases.[rx]
HIHRATL – Hereditary infantile hemiparesis, retinal arteriolar tortuosity, and leukoencephalopathy
HERNS – Hereditary epitheliopathy with retinopathy, nephropathy, and stroke
Triggers
Withdrawn or exposed to several factors contribute to the development of migraine headaches.[rx] A retrospective study found that 76% of the patients reported triggers.[rx] Some of them are probable factors that contribute, while others are only possible or unproven factors.
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Stress in 80% (probable factor)
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Hormonal changes in 65% during menstruation, ovulation, and pregnancy (probable factor)
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Skipped meals 57% (probable factor)
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Weather changes in 53% (probable factor)
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Excessive or insufficient sleep in 50% (possible factor)
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Odors in 40% (perfumes, colognes, petroleum distillates)
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Neck pain in 38%
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Exposure to lights in 38% (probable factor)
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Alcohol ingestion in 38% (wine as a probable factor)
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Smoking in 36% (unproven factor)
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Late sleeping in 32%
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Heat in 30%
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Food in 27% (aspartame as a possible factor, and tyramine and chocolate as unproven factors)
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Exercise in 22%
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Sexual activity in 5%
Pathophysiology
At first, there was a vascular theory of migraine, which explained that the headache was produced by vasodilation and aura by vasoconstriction, but this theory is not viable anymore.[rx] Nowadays, the suggestions pose that multiple primary neuronal impairments lead to a series of intracranial and extracranial changes that cause migraines.[rx]
The cortical spreading depression of Leão, a propagating wave of neuronal and glial depolarization that initiates a cascade, is hypothesized to cause the aura, activate trigeminal afferents, and alter the hematoencephalic barrier permeability by activating brain matrix metalloproteinases.[rx] In migraine without aura, the suggestions are that cortical depression may occur in areas where depolarization is not consciously perceived, such as the cerebellum.[rx] There is activation of trigeminal afferents by neuronal pannexin-1 mega channel opening and subsequent activation of Caspase-1, followed by the release of proinflammatory mediators, activation of NF-kB (nuclear factor kappa-B), and spreading of this inflammatory signal to trigeminal nerve fibers around vessels of the pia mater.[rx] This causes a series of cortical, meningeal, and brainstem events, provoking inflammation in the pain-sensitive meninges that concludes in headache through central and peripheral mechanisms.[rx][rx] This pathway can, therefore, explain the cortical depression (which establishes the aura) and the latter prolonged activation of trigeminal nociception (which leads to headache).
The anterior structures are most innervated by the ophthalmic division of the trigeminal nerve, which could explain the pain in the anterior region of the head. There is a convergence of fibers from the upper cervical roots which originate the trigeminal nerve neurons along with the trigeminal ganglion and the trigeminal nerve at the trigeminal nucleus caudalis which can explain the anterior to the posterior distribution of pain, from where the fibers ascend to the thalamus and the sensory cortex.[rx]
Neurogenic inflammation, which is based on vasodilation, edema, and plasma protein extravasation, results from nociceptor activation; in this case, the trigeminal system. It is associated with the release of substance P, calcitonin gene-related peptide, and neurokinin a; all vasoactive neuropeptides liberated by trigeminal ganglion stimulation.[rx] Elevated levels of these neuropeptides have been found in the spinal fluid of chronic migraine patients.[rx][rx] Neurogenic inflammation can lead to sensitization, which is the process in which neurons tend to become more responsive to stimulation. This can explain some clinical symptoms of the pain and the conversion from episodic migraine to a chronic one.[rx]
Serotonin, released from the brainstem serotonergic nuclei, may play a role in migraine; however, the exact role of its mechanisms remains a matter of controversy. Most likely, serotonin levels are low between attacks because it may cause a deficiency in the serotonin pain inhibition system, therefore helping the activation of the trigeminal system. It could mediate by acting directly over the cranial vessels, or in central pain control pathways, or by cortical projections of brainstem serotonergic nuclei.[rx][rx]
Calcitonin gene-related peptide is abundant in trigeminal ganglion neurons. It is released from the peripheral nerve and central nerve terminals as well as secreted within the trigeminal ganglion. When released from the peripheral terminals, it initiates an increased synthesis of nitric oxide and latter sensitization of trigeminal nerves.[rx][rx] It is a strong vasodilator of cerebral and dura mater vessels, therefore a component of neurogenic inflammation, and it also mediates trigeminal pain transmission from vessels to the central nervous system.
Diagnosis of
Migraine attacks occur through four phases:[rx]
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Around 77% of patients suffer prodromic symptoms up to 24 to 48 hours before headache onset. It is more common in females than males (81% to 64%).
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Frequent symptoms are yawning (34%), mood change, lethargy, neck symptoms, light sensitivity, restlessness, difficulties in focusing vision, feeling cold, craving, sound sensitivity, sweating, excess energy, thirst, edema
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Aura: changes in cortical function, blood circulation, and neurovascular integration. It occurs in about 25% of the cases.[rx][rx][rx][rx]
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It can precede the headache, or it can present simultaneously.
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They are typically gradual, with less than 60 minutes of duration, more often visual, and have positive and negative symptoms.
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Positive symptoms are caused by active release from central nervous system neurons (bright lines or shapes, tinnitus, noises, paresthesias, allodynia, or rhythmic movements).
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Negative symptoms point out a lack or loss of function (reduction or loss of vision, hearing, sensation, or motion).
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They have to be fully reversible.
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Visual auras are the most frequent ones.
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The most common positive visual symptom is the scintillating scotoma (an area of absent vision with shimmering or glittering zigzag border).
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The most common negative visual symptom is the visual field defects.
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Sensory auras are also common. They can follow visual symptoms or occur without them.
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It usually consists of tingling sensations on one side of the face or a limb. They are considered as paresthesias.
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Language auras are not frequent. They consist of a transient dysphasia.
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Motor auras are rare. They consist of complete or partial hemiplegia that can involve limbs and face.
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Headache: additional changes in blood circulation and function of the brainstem, thalamus, hypothalamus, and cortex.
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Often unilateral, generally with a pulsatile or throbbing feature and increasing intensity within the first hours.
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The intensity can correlate to nausea, vomiting, photophobia, phonophobia, rhinorrhea, lachrymation, allodynia, and osmophobia.
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It can take place over hours to days.
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Patients may have to seek relief in dark places, as the pain usually resolves in sleep.
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Postdrome: persistent blood changes with symptoms after headache termination.
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This phase consists of a movement-vulnerable pain in the same location as the previous headache.
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Common symptoms can be exhaustion, dizziness, difficulty concentrating, and euphoria.
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Evaluation
The diagnosis of migraine is based on patient history, physical examination, and fulfillment of the diagnostic criteria. The necessary information that has to be gathered consists of these simple questions:
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Demographic features of the patient: age, gender, race, profession
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When did the headache start?
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Where does it hurt? Location, irradiation.
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What is the intensity of the pain?
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How is the pain? Which are the qualitative characteristics of the pain?
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How long does the pain last?
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In which moment of the day does the pain appear?
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How has it evolved since it started?
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What is the frequency of appearance?
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What are the triggering situations?
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Simultaneous symptoms?
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Is it related to sleep?
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How does it get better or worse?
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Which medications do you take to make it better? What is the frequency of this medication?
The International Classification of Headache Disorders (ICHD-3) describes these diagnostic criteria.[rx]
B1. Migraine without aura:
- B1a. Headache attacks lasting 4 to 72 hours (untreated or unsuccessfully treated)
- B1b. Headache has at least two of the following characteristics:Unilateral location
- Pulsating quality
- Moderate or severe pain intensity
- Aggravation by or causing avoidance of routine physical activity (walking or climbing stairs)
B1c. During headache at least one of the following:
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Nausea and vomiting
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Photophobia and phonophobia
B2. Migraine with aura:
B2a. One or more of the following fully reversible aura symptoms:
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Visual
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Sensory
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Speech and language
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Motor
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Brainstem
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Retinal
B2b. At least two of the following characteristics:
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At least one aura symptom spreads gradually over ≥5 minutes
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Two or more aura symptoms occur in succession
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Each aura symptom lasts 5 to 60 minutes
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At least one aura symptom is unilateral
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At least one aura symptom is positive
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The aura is accompanied, or followed within 60 minutes, by a headache
C. On eight days or more per month for more than three months, fulfilling any of the following:
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Criteria B1b and B1c for migraine without aura
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Criteria B2a and B2b for migraine with aura
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It is believed by the patient to be migraine at onset and relieved by a triptan or ergot derivative
D. Not better accounted for by another ICHD-3 diagnosis
The ICHD-3 criteria for migraine without aura are
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At least five attacks fulfilling criteria B to D (see below)
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Headache attacks that last 4 to 72 hours, untreated or unsuccessfully treated
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Headache that has at least two of the following criteria:
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Unilateral location
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Pulsating quality
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Moderate to severe pain intensity.
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Aggravation by or causing avoidance of routine physical activity (as walking or climbing stairs)
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During headache at least one of the following:
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Nausea, vomiting, or both
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Photophobia and phonophobia
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Not better accounted for by another ICHD-3 diagnosis
The ICHD-3 criteria for migraine with aura are
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At least two attacks fulfilling criteria B to D
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One or more of the following fully reversible aura symptoms:
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Visual
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Sensory
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Speech and language
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Motor
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Brainstem
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Retinal
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At least three of the following six characters:
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At least one aura symptom spreads gradually over ≥5 minutes
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Two or more symptoms occur in succession
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Each aura symptom lasts 5 to 60 minutes
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At least one aura symptom is unilateral
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At least one aura symptom is positive
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The aura is accompanied, or followed within 60 minutes, by a headache
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It is not better accounted for by another ICHD-3 diagnosis
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Hemiplegic migraine is diagnosed when the aura consists of motor weakness.
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Migraine with brainstem aura (previously known as basilar artery migraine or basilar migraine) is diagnosed if the aura symptoms emerge from the brainstem (bilateral hemianopic visual disturbance, diplopia, vertigo, ataxia, dysarthria, tinnitus, hyperacusis, bilateral paresthesia, or numbness)
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Retinal migraine is diagnosed when the aura involves a monocular visual field defect.
The ICHD-3 criteria for chronic migraine are
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Headache (tension-type-like or migraine-like) on 15 or more days per month for more than three months and fulfilling criteria B and C
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It is occurring in a patient who has had at least five attacks fulfilling the following criteria for migraine without aura (B1) or migraine with aura (B2)
Neuroimaging (computed tomographic scan, magnetic resonance imaging, magnetic resonance angiography, or magnetic resonance venography) is indicated in the following cases:[rx][rx]
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Acute severe headache, especially if it is the first or worst episode (to discard subarachnoid hemorrhage).
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Abnormal neurologic examination, especially if there are unexplained symptoms or signs (confusion, stiff neck, papilledema, epilepsy).
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Non-typical characteristics.
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Changes in the patient’s typical features or patterns
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Resistance to treatment.
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New episodes in older (>50 years of age) or immunosuppressed patients.
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Systemic or meningeal signs or symptoms (fever, weight loss, fatigue)
The commonly used acronym “SNOOP” can be used to aid in the determination of neuroimaging indications:
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“S” for systemic signs or symptoms, and secondary risk factors
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“N” for neurologic signs or symptoms
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“O” for onset
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“O” for older
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“P” for position-dependent intensity changes, prior pattern changes, papilledema, and precipitated by Valsalva maneuvers.
Cerebrospinal fluid analysis and electroencephalogram are not typically performed unless seizure activity of infectious etiology has to be excluded.
Treatment
Treatment options are based on the onset scenarios: acute or chronic.
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Acute or Abortive treatment: acute treatment aims to stop the progression of a headache. It has to be treated quickly, and with a large single dose. Oral agents can be ineffective in patients with migraine-induced gastric stasis. For that reason, parenteral medication could be the rule for some patients, especially the ones with nausea or vomiting. Therapy consists of stratified options:[rx][rx][rx]
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NSAIDs (nonsteroidal anti-inflammatory drugs): ibuprofen, naproxen, diclofenac, aspirin, or acetaminophen. Usually in mild to moderate attacks without nausea or vomiting.
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Triptans (the first-line in patients with allodynia): sumatriptan, eletriptan, rizatriptan, almotriptan. With or without naproxen for moderate to severe attacks.
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Triptans should be limited to less than ten days of use within a month to avoid medication overuse.
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Because of the activation of the 5-HT(1B) and 5-HT(1D) receptors on coronary arteries and cerebral vessels, there are recommendations against its use in patients with ischemic stroke, ischemic heart disease, poor-controlled hypertension, angina, pregnancy, hemiplegic or basilar migraine. In these patients, with cardiovascular risks, the best-suited medication is a selective serotonin 1F receptor agonist that does not produce vasoconstriction; lasmiditan.
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It is recommended to monitor therapy if the patient takes selective serotonin reuptake inhibitors or selective serotonin-noradrenaline reuptake inhibitors because of the risk of serotonin syndrome.
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Antiemetics: metoclopramide, chlorpromazine, prochlorperazine. They are generally used as adjunctive therapy with NSAIDs or triptans to decrease nausea and vomiting, especially in the emergency department. Diphenhydramine can also be added to prevent dystonic reactions (mostly with metoclopramide).
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Calcitonin-gene related peptide antagonists: rimegepant, ubrogepant. It could be considered in patients that don’t respond to conventional treatment or in those with coronary artery disease.[rx]
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Ergots: ergotamine and dihydroergotamine, being this last one the only one recommended for acute attacks as a parenteral administration, and effective as bridge therapy for medication overuse headache and status migrainosus. Ergotamine has not demonstrated particular effectiveness yet, and it can present significant side effects.
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Transcutaneous supraorbital nerve stimulation can reduce intensity.[rx]
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Prophylactic or preventive treatment: preventive treatment aims to reduce attack frequency, and improve responsiveness to acute attacks severity and duration, and reduce disability.[rx][rx] Migraine triggers have to be documented by each individual to reduce them in the future.
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Indications for preventive treatment are:
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Frequent or long-lasting headaches
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Attacks that cause significant disability and reduced quality of life
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Contraindication or failure to acute therapies
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Significant adverse effects of abortive therapies
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Risk of medication overuse headache
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Menstrual migraine (along with short-term premenstrual prophylaxis)
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Hemiplegic migraine
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Brainstem aura migraine
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Persistent aura without infarction
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Migrainous infarction
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Preventive treatment agents are the following:
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Beta-blockers: metoprolol and propranolol. Especially in hypertensive and non-smoker patients.
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Antidepressants: amitriptyline and venlafaxine. Especially in patients with depression or anxiety disorders, and insomnia.
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Anticonvulsants: valproate acid and topiramate. Especially in epileptic patients.
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Calcium channel blockers: verapamil and flunarizine. Especially in women of childbearing age or patients with Raynaud’s phenomenon.
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Calcitonin gene-related peptide antagonists: erenumab, fremanezumab, and galcanezumab.
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Alternative treatment:
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Changes in lifestyle; must be a commitment from the patient; however, social support is of great importance to improve mental health to help the patient’s involvement.
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Regular exercise
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Yoga
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Relaxation training
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Cognitive-behavioral therapy
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Biofeedback
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Reduction of triggers
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Detoxification
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Butterbur
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Melatonin
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Children and Headache
Headaches are common in children. Headaches that begin early in life can develop into migraines as the child grows older. Migraines in children or adolescents can develop into tension-type headaches at any time. In contrast to adults with migraines, young children often feel migraine pain on both sides of the head and have headaches that usually last less than 2 hours. Children may look pale and appear restless or irritable before and during an attack. Other children may become nauseous, lose their appetite, or feel pain elsewhere in the body during the headache.
Headaches in children can be caused by a number of triggers, including emotional problems such as the tension between family members, stress from school activities, weather changes, irregular eating and sleep, dehydration, and certain foods and drinks. Of special concern among children are headaches that occur after a head injury or those accompanied by rash, fever, or sleepiness.
It may be difficult to identify the type of headache because children often have problems describing where it hurts, how often the headaches occur, and how long they last. Asking a child with a headache to draw a picture of where the pain is and how it feels can make it easier for the doctor to determine the proper treatment.
Migraine in particular is often misdiagnosed in children. Parents and caretakers sometimes have to be detectives to help determine that a child has a migraine. Clues to watch for include sensitivity to light and noise, which may be suspected when a child refuses to watch television or use the computer, or when the child stops playing to lie down in a dark room. Observe whether or not a child is able to eat during a headache. Very young children may seem cranky or irritable and complain of abdominal pain (abdominal migraine).
Headache treatment in children and teens usually includes rest, fluids, and over-the-counter pain relief medicines. Always consult with a physician before giving headache medicines to a child. Most tension-type headaches in children can be treated with over-the-counter medicines that are marked for children with usage guidelines based on the child’s age and weight. Headaches in some children may also be treated effectively using relaxation/behavioral therapy. Children with cluster headaches may be treated with oxygen therapy early in the initial phase of the attacks.
Headache and Sleep Disorders
Headaches are often a secondary symptom of a sleep disorder. For example, tension-type headache is regularly seen in persons with insomnia or sleep-wake cycle disorders. Nearly three-fourths of individuals who suffer from narcolepsy complain of either migraine or cluster headache. Migraines and cluster headaches appear to be related to the number of and transition between rapid eye movement (REM) and other sleep periods an individual has during sleep. Hypnic headache awakens individuals mainly at night but may also interrupt daytime naps. Reduced oxygen levels in people with sleep apnea may trigger early morning headaches.
Getting the proper amount of sleep can ease headache pain. Generally, too little or too much sleep can worsen headaches, as can the overuse of sleep medicines. Daytime naps often reduce deep sleep at night and can produce headaches in some adults. Some sleep disorders and secondary headaches are treated using antidepressants. Check with a doctor before using over-the-counter medicines to ease sleep-associated headaches.
Coping with Headache
Headache treatment is a partnership between you and your doctor, and honest communication is essential. Finding a quick fix to your headache may not be possible. It may take some time for your doctor or specialist to determine the best course of treatment. Avoid using over-the-counter medicines more than twice a week, as they may actually worsen headache pain and the frequency of attacks. Visit a local headache support group meeting (if available) to learn how others with headaches cope with their pain and discomfort. Relax whenever possible to ease stress and related symptoms, get enough sleep, regularly perform aerobic exercises, and eat a regularly scheduled and healthy diet that avoids food triggers. Gaining more control over your headache, stress, and emotions will make you feel better and let you embrace daily activities as much as possible.
What Research is Being Done?
Several studies either conducted or supported by the National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health, are revealing much about the headache process and may lead to new treatments or perhaps ways to block debilitating headache pain. Studies by other investigators are adding insight to headache etiology and treatment.
Understanding headache mechanisms and underlying causes
The molecular basis for migraine headaches and the aura associated with certain migraines is uncertain. One multi-faceted research study is examining how migraine with aura may affect metabolism and neurophysiological function. Investigators are also studying if particular regions of the visual cortex are unusually susceptible to the events in the brain that cause the aura. Another study component is investigating what happens at the beginning of a headache and how changes in the brain’s meninges may lead to vascular and trigeminal nerve stimulation associated with the painful part of a migraine headache. Results may provide a greater understanding of migraine and assist the development of new therapies.
Mast cells, which are part of the immune system and are involved in the inflammatory allergic response, are activated in some chronic pain conditions, including headache. Researchers are examining the possibility of a relationship between the mast cells’ anti-analgesic properties and their proximity to and enhanced activation of nerve fiber endings that receive and transmit pain signals (nociceptors). Mast cells may release substances that activate nociceptive nerve cells that transmit signals from the linings of the skull and its blood vessels. Findings that link mast cell activation to headache pain may identify drug targets that could lead to new analgesics for headache and other pain syndromes.
Cortical spreading depression (CSD) is a process in migraine with aura in which a wave of increased brain activity, followed by decreased activity, slowly spreads along the brain’s surface. The wave of brain activity often travels across the part of the brain that processes vision and corresponds to the typical visual aura of migraine. Research has shown that migraines with aura may be associated with tiny areas of stroke-like brain damage caused by a short-term drop in oxygen levels (associated with the CSD) which prevents normal cell function and swelling in the brain’s nerve cells. Animal studies have shown that CSD also irritates the trigeminal nerve, causing it to transmit pain signals and trigger inflammation in the membranes that surround the brain. CSD inhibiting drugs such as tonabersat are being tested in clinical trials for their usefulness in treating migraine and other neurological diseases. Other investigators hope to build on initial results showing that estrogen withdrawal makes it easier for CSD to occur in the brains of animals, which may explain the contribution of estrogen fluctuation to menstrual migraines. This research may result in a better understanding of how a migraine starts in the brain and offer new methods of treatment by interrupting this process and preventing the migraine.
Cutaneous allodynia is the feeling of pain or unpleasant sensations in response to normally nonpainful stimuli, such as light touch. Researchers are investigating why it is present on the head or face in people with cluster headaches, to better understand neurological changes that occur with these headaches. Similar research is looking at why some people with migraines have more than the typically restricted allodynia that affects a particular area of the head predicted by the headache (for example, on the same side of the face as the migraine pain). Individuals with extended allodynia may experience unpleasant sensations on the side of the face opposite the headache pain or even on their feet. Previous studies have shown that sensitized nociceptors in the brain’s coverings are involved in the throbbing pain of migraine and that other sensitized neurons found deeper in the brain are involved with restricted allodynia, but it is not certain which cells are responsible for extended allodynia. Future studies will explore whether nerve cells in the thalamus (which is involved in relaying signals between the brain and the body) become more sensitive a result of headache pain and cause extended allodynia. Findings may offer a better understanding of how the nervous system changes and becomes more sensitive after repeated stimulation, resulting in chronic pain.
Social and other factors may impact headaches. Researchers are examining how race and psychiatric conditions are related to headache severity, quality of life, the ability to reliably follow a treatment program, and treatment response in people with migraines, tension-type headache, substance abuse headache, or cluster headache.
Genetics of headache
Genetics may contribute to a predisposition for migraines. Most migraine sufferers have a family member with migraine. Researchers are studying the activity of different genes to see if they make some people more likely to have migraines. One strategy is to test for a gene in several families having members with migraines and then determine if the gene is related to migraine in a broader population.
In April 2008, researchers at the University of Helsinki reported significant evidence for linkage between a gene variant on a specific site on chromosome 10q22-q23 and susceptibility to common types of migraine. The findings were from a study of 1,675 migraine sufferers or their close relatives from 210 Finnish and Australian migraine families. Another study replicated the findings in the two populations and also showed that the site was particularly linked to female migraine sufferers. Although it has been known for some time that genetic factors shared by family members make people more susceptible to migraines, this study is the first to identify convincingly a specific gene locus for common forms of migraine.
Currently under investigation are gene expression patterns (signs of changes in gene activity) in the blood of individuals during migraine attacks and among individuals with chronic daily headaches. Preliminary studies show that children with acute migraines and chronic daily headaches have specific similar gene expression profiles in their blood that are different from healthy individuals and from children with other non-related neurological diseases. Researchers are exploring differences in gene expression profiles among individuals who respond to different types of headache drugs. Study results may indicate a molecular genomic approach using blood samples to detect genes that may be activated during headaches and identify which drugs are best used for each person with migraines.
Scientists are exploring the role of the calcitonin gene-related peptide (CGRP) in migraines. Levels of the CGRP molecule, which is involved in sending signals between neurons, increase during migraine attacks and revert to normal when the pain resolves. Researchers plan to use CGRP as a model and then to use functional magnetic resonance imaging to estimate the pain response in the central nervous system. Evidence from individuals with Familial Hemiplegic Migraine (FHM) with known mutations indicates that migraine pathways in FHM may be different from normal migraine. Investigators are also measuring levels of CGRP during the premonitory, mild, moderate, and severe phases of a single migraine compared to the baseline level when individuals are pain-free. The fluctuations of CGRP during the migraine process will help to define its role in migraine pain and may offer new opportunities for acute treatment.
Clinical studies in headache management
A major focus of headache research is the development of new drugs and other treatment options. Several drug studies seek to identify new drugs to treat various headache disorders and to find safer, more effective doses for medications already being used. Other research is aimed at identifying receptors or drug targets to stop the process of migraine aura in the brain.
Results of three randomized, placebo-controlled clinical trials show the drug topiramate is effective, safe, and generally well-tolerated for treating chronic migraine. Experts agree that treatment with combinations of preventive agents offers maximum relief for the majority of individuals with chronic migraines. An NINDS-funded clinical trial is examining the effectiveness and safety of the drug propranolol combined with topiramate in reducing the frequency of chronic migraine in 250 participants who will be randomly selected to receive treatment with both drugs or topiramate and placebo.
Sleep plays an important role in migraine. Migraine in older adults is sometimes triggered by sleep changes; regulating their sleep may lessen the frequency of migraines. Younger migraine sufferers often report migraine relief after sleep. Researchers are studying the use of the drug ramelteon, which is approved by the U.S. Food and Drug Administration for insomnia, in reducing the number of migraines over a 12-week period.
Headache is the most common symptom after a closed head injury, and it can last for more than 2 months in 60 percent of affected individuals. Unfortunately, individuals with chronic post-traumatic headaches also have cognitive and behavioral problems, and many drugs currently used to treat the headaches also have a negative influence on cognition. Scientists are testing different drugs, such as naratriptan (which acts as a neurotransmitter) and galantamine (used to treat Alzheimer’s disease), to treat both headache and cognitive disturbances in individuals with chronic post-traumatic headaches.
Non-pharmaceutical approaches to treatment and prevention
Historically, very little research has been done on children with headaches. A variety of headache education and drug and/or behavioral management techniques are aimed at improving headache treatment and prevention in children and adolescents. Scientists are testing the effectiveness of combined pain coping skills (including age-appropriate biofeedback, muscle relaxation techniques, imagery, activity pacing, and the use of calming techniques) and the drug amitriptyline in reducing headache frequency, intensity, and depressive symptoms in youth ages 10 to 17 years. Additional studies include the use of alternative approaches such as yoga to decrease headaches in adolescents, a modified diet to treat chronic daily headaches in teenagers, and programs designed to teach very young children how to understand and self-manage their headaches.
Craniosacral therapy (CST) involves gentle massaging of the neck, head, and spine to release constraints in tissue in the head and around the spine. Limited preliminary data shows significant, the sustained benefit of CST in a small group of individuals with migraines. Future research will gather data on the usefulness of CST in preventing migraines and examine the feasibility of a larger, randomized trial.
Electrical stimulation of the occipital nerve has effectively eased the symptoms of painful chronic headache conditions such as cluster headache as well as hard-to-treat migraine in small clinical studies. A tiny battery-powered rechargeable electrode, surgically implanted near the occipital nerve, sends continuous energy pulses to the nerve to ease pain. The use of this non-drug treatment in reducing migraine frequency, intensity, and effect on the quality of life is being tested in larger clinical trials.
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