What is Migraine? Triggers, Diagnostic Criteria, and Aura Symptoms

Migraine is the second most common cause of headache and most common headache-related cause of disability in the world. It results from altered modulation of normal sensory stimuli and trigeminal nerve dysfunction. These headaches affect 12% of adult population and cause a significant economic loss in productivity.


Migraineurs are particularly sensitive to environmental and sensory stimulus. This sensitivity is amplified in females during menstrual cycleas a result of estrogen shifts; these are catamenial migraines that occur regularly in at least two of three consecutive menstrual cycles and occur exclusively on day 1 or 2 of menstruation. Headache can be initiated or amplified by various triggers, including glare, bright lights, sounds, or other types of afferent stimulation; hunger; let down from stress; physical exertion; stormy weather or barometric pressure changes; hormonal fluctuations during menses; lack of or excess sleep and alcohol or other chemical stimulation such as with nitrates.

Diagnostic Criteria

The International Headache Society has produced the following diagnostic criteria for migraine without aura:Â


  1.  At least 5 attacks fulfilling criteria B-D
  2.  Headache attacks lasting 4-72 hours* (untreated or unsuccessfully treated)
  3. Headache has at least two of the following characteristics:
  • unilateral location*
  • pulsating quality (i.e., varying with the heartbeat)
  • moderate or severe pain intensity
  • aggravation by or causing avoidance of routine physical activity (e.g., walking or climbing stairs)
  1. During headache at least one of the following:
  • nausea and/or vomiting
  • photophobia and phonophobia
  1. Not attributed to another disorder (history and examination do not suggest a secondary headache disorder or, if they do, it is ruled out by appropriate investigations or headache attacks do not occur for the first time in close temporal relation to the other disorder)

Note that

Tension type headache must be differentiated from migraine, the former is featureless, while migraine has features described above in point criteria. Most patients with disabling headache probably have migraine.

In children, attacks may be shorter-lasting, headache is more commonly bilateral, and gastrointestinal disturbance is more prominent.

Migraine with aura (seen in around 25% of migraine patients) tends to be easier to diagnose with a typical aura being progressive in nature and may occur hours prior to the headache. Aura is subject sensation or perception that signals the impending onset of neurological event. Typical aura include flashing lights or zigzag lines spreading across the visual field(‘jagged crescent’). Sensory symptoms may also occur such as tingling or numbness in face or extremities or auditory hallucinations.

If we compare these guidelines to the NICE criteria(National Institute for Health and Care Excellence) the

following points are noted:

  • NICE suggests migraines may be unilateral or bilateral
  • NICE also give more detail about typical auras:
  • Auras may occur with or without headache and:
  • are fully reversible
  • develop over at least 5 minutes
  • last 5-60 minutes

The following aura symptoms are atypical and may prompt further investigation/referral;

  • motor weakness
  • double vision
  • visual symptoms affecting only one eye
  • poor balance
  • decreased level of consciousness.

Written By: Dr. Maisam Raza

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