MIGRAINE

“It’s not just pain. It’s a complete physical mental and emotional assault on your body,” said Jamie Wingo Hins about Migraine.

Migraine is a common, multifactorial disabling, recurrent hereditary neurovascular headache disorder. It is one of the oldest ailments known to mankind. The recorded data dates back to 1200 BC by ancient Egyptians.

Aretaeus of Cappadocia described Migraine in second century AD as a one sided / unilateral headache that is typical of Migraine as well as the associated vomiting and headache free intervals between attacks. 

However, it was only in late 1930, that Graham and Wolff reported ergotamine tart could relieve Migraine.

By now, migraine is accepted as a real disorder which affects around one in seven people, two third of whom are women and is recognized by WHO as the sixth highest case world wide of years lost due to disability.

Epidemiology

WHO ranks migraine as the third most prevalent medical condition and the second most disabling neurological disorder in the world. The prevalence of migraine peaks in both sexes during the most productive years of adulthood (25 to 55 years) and prevalence is higher in the low socio-economic status. It frequently starts in childhood, particularly around puberty and affects women more than men (3:1 female to male ratio).

Symptoms

Migraine may be characterized as episodic (Fewer than 15 days per month) or chronic (15 days or more per month). Clinically patients with migraine may seem normal between attacks. It also has many characteristic triggers that may be viewed as the interaction of environmental triggers and susceptible host. And these triggers include exertion, dietary factors (including delaying meal), sleep disturbances, head trauma, hormonal influences and medication. Loud noise, certain odors, certain foods (or delaying meal), all may act as triggers for migraine.

Migraine symptoms can occur in different phases: Premonitory phase, Aura, Headache, resolution and postdrome phase. 

Premonitory Phase: -

This is the earliest stage of migraine attack and starts in the CNS.

Example: - Yawning, polyurea, food cravings and mood changes are all may be the prelude of Migraine.

Aura: -

Aura occurs in only about 20% of patients with migraine. The most common manifestation is visual, often an enlarging scotoma with a shimmering edge (Fortification spectra or teichopsia). Patient may also see stars, dots, wavy lines, complex pattern, shapes of visual distortion. Less common are sensory areas, here paresthesia begins in the hand and slowly over minutes ascends to the shoulder and may spread to ipsilateral face and even inside of the mouth and tongue.

Headache Phase: -

Migraine headache is often reported by patients to the unilateral throbbing and aggravated by physical activity or head movement. The headache can change sides during or between attacks. The median time to peak intensity is one hour and median duration in 24 hours. The duration of migraine headache can range from 4 to 72 hours in adult and 2 to 48 in children. 

75% patients have neck pain that accompanies migraine attack. There also may be photophobia, phonophobia, dizziness, anorexia and nausea along with migraine headache and one third of patients may have vomiting. 16% patients may have diarrhoea.

 Postdromal Phase: -

This phase is defined as the stage from when the headache resolves to when the individual feels completely back to normal.

This occurs in 80% of individuals with migraine. It usually lasts less than 12 hours but can persist for longer than 24 hours in approximately 12% of patients. The most common symptoms during this phase is asthenia, fatigue, somnolence, impaired concentration, photophobia, irritability and nausea.

Pathophysiology of Migraine 

Migraine is typically hereditary although the condition is usually polygenus. Many patients have first degree relatives who also suffer from migraine. Transmission of migraine from parents to children has been reported from as early as the 17th century.

The cause of aura is in a mechanism in the CNS called cortical spreading depression.

Surrounding the large cerebral vessels, pial vessels, large venous sinuses and dura matter is a plexus of largely unmyelinated fibers that arises from ophthalmic division of trigeminal ganglion and in the pastier fossa from upper cervical dural roots. Trigeminal fibers innovating cerebral vessels arises from neurons that contain substance P and Calcitonin gene related peptide both of which can be released when trigeminal ganglion is stimulated in the human.

Stimulation of the cranial vessels such as superior sagittal sinus is certainly painful in humans. Moreover, each symptom of migraine has complicated Pathophysiology.