“cortical spreading depression,” a slowly propagating wave of neuronal hyperpolarization followed by depolarization This in turn triggers a neuronally mediated vascular instability that results in intracranial hypoperfusion (which may produce the migraine aura of premonitory motor, visual, or sensory symptoms), followed by vasodilation and a sterile, neurogenic inflammation, which are responsible for the headache Clinical Considerations Clinical Recognition Prolonged (up to 24 to 48 hours), moderate to severe headache is characteristic of migraine The headaches may be pulsating and unilateral but this pattern is less common in children than in adults Migraine is commonly associated with nausea, vomiting, abdominal pain, and photophobia or phonophobia Auras occur in less than half of children Occasionally, the attacks awaken the children from sleep A family history of migraine is helpful in diagnosis, and a disproportionate number of children who experience migraines have episodes of motion sickness, dizziness, vertigo, or frank paroxysmal events Initial Evaluation The diagnosis of migraine is based almost exclusively on the history and is supported by the absence of abnormalities on examination There are no diagnostic laboratory tests or imaging studies The physical examination usually shows no focal neurologic deficits, although hemiplegia and ophthalmoplegia may occur in complicated migraine Common trigger factors for migraine in children include emotional stress, lighting changes, and minor head trauma Particularly in adolescents, it is useful to screen for depression or other psychosocial stressors that may warrant separate treatment Nitrates (e.g., lunch meats) and tyramine (cheeses) are less common but important food triggers Given an accurate history, differentiation from tension headaches, sinusitis, and headaches secondary to intracranial lesions is usually possible; studies such as EEG, CT, and MRI are rarely indicated In children with focal neurologic deficit and no prior history of such episodes due to migraine, urgent neuroimaging should be considered Initial evaluation should include a determination of the level of pain using a validated scale For patients with known migraine, establishing a target pain level for acute treatment is also helpful