11 June 2009


From Brain Blogger Dr. Shaheen Lakhan's interview with headache expert Dr. Roger K Cady, a bit about the current understanding of what migraines are:

Shaheen Lakhan: To start off, what sets a migraine apart from a tension-type headache?

Roger Cody: ...tension headache is a headache without the presence of other symptoms. The headache is generally mild to moderate in intensity, more likely to be on both sides of the head and with a steady and pressure quality to the pain. It is not associated with nausea or sensitivity to light or sound.

Migraine is the most common headache causing people to seek medical attention. Migraine is always more than just a headache. The headache can be on one or both sides of the head and more likely to have a throbbing quality or to be made worse by daily activity or things like bending over. Associated with the headache are symptoms like nausea and sensitivity to light, sound, and other sensory stimuli.
In people with migraine, many experts suggest that migraine and tension headaches exist on the same spectrum and arise out of the same pathophysiological process (big and little migraines).

SL: I recall the vascular theory of migraine from decades past which held that migraine symptoms were a function of ischemia and hyperemia. How far have we advanced in understanding the pathogenesis of migraine?

RC: The pathophysiology of migraine has changed dramatically over the last 2 decades. Today migraine is understood as a neurological disease with a genetic predisposition. Sufferers inherit a nervous system that is more vigilant of its surroundings than the brain of a non-migraineur, and this nervous system has an enduring predisposition to recurrent attacks of migraine triggered by events that do not produce migraine in the general population. This tendency spans decades of life for most migraineurs. Migraine is the quintessential example of how the genetic makeup of the individual and their environment can interact to produce an attack of migraine and over time the disease of migraine.

An attack of migraine occurs when the nervous system encounters triggering events that overwhelm the brain’s capacity to adjust. The first phase of a migraine is called the premonitory period or prodrome. This period is characterized by non-headache symptoms such as fatigue, cognitive change, sensory sensitivity, nasal congestion, muscle pain, yawning. This can be a warning for many people that an attack of disabling migraine is inevitable.

The second phase is called the aura and occurs in approximately 30% of attacks. This represents an electrical event in the brain called spreading cortical depression and produces a period of neurological changes that can last up to one hour but the symptoms are fully reversible. Symptoms generally are visual such as flashing lights or sensory such as numbness in the face or upper extremity.

The third phase is the headache phase. It usually begins with a mild headache that progresses sometimes very rapidly into a moderate to severe headache that is associated with nausea, sometimes vomiting and sensory sensitivity to light, sound, touch, and smell. Also there is frequently muscle pain in the head, neck, and shoulders and nasal congestion or “sinus” symptoms. However, large studies consistently show that what most physicians or patients consider sinus headache is actually migraine. This generally causes a person to seek refuge in a dark quiet place and generally lasts from 4-72 hours.

The final phase is called the postdrome. Sometimes it is referred to as the migraine hangover and consists of muscle aches and pain, slowed cognition, fatigue, and general malaise that can last up to another 24 hours. More rarely, some people experience a boost in energy and elation.

Read the whole thing here

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