Bright Sight

Oliver Backhouse, Consultant Eye Surgeon www.cataract.org.uk

Migraine

Migraine is a common neurological condition occurring in at least 15-20% of the population and in upto 50% of women. Classical migraine usually starts with visual symptoms (often zig-zag lines, coloured lights or flashes of light expanding to one side of your vision over 10-30 minutes), followed by a single-sided pounding headache. The headache is usually associated with nausea, vomiting, and light sensitivity. Sometimes visual symptoms and even neurological dysfunction may occur without the headache. This is called ‘migraine-variant’. Common migraine may cause only a headache felt on both sides of the head. This form of migraine may be responsible for the headaches that many people may have attributed to tension, stress or sinus pain.

1] What causes Migraine?

While it is not clear exactly how a migraine works, it is believed that the basic cause of migraine is an abnormality in the neurotransmitter serotonin, an important chemical used by your brain cells. During a migraine attack, changes in serotonin affect blood vessels in your brain, often causing the vessels to constrict. These changes in blood flow decrease the oxygen supply to the brain. If this oxygen supply is decreased long enough, a stroke is possible. Fortunately this is rare.

Certain foods may trigger a migraine attack including aged cheese, nitrates (often found in cured meats and processed foods), chocolate, red wine and monosodium glutamate (a flavour enhancer frequently found in some foods). Caffeine, aspartame (artificial sweetener) and alcohol may also trigger migraines. Hormonal changes are frequently associated with migraine, especially pregnancy, use of birth control pills, and menstrual periods or menopause.

Patients often attribute migraine to stress. While stress probably does not cause migraine, it may affect the frequency of attacks. Interestingly, however, most migraine attacks seem to occur following stress relief, often at the beginning of a weekend or holiday. People who experience migraine, often have a family history of migraine or motion sickness.

2] What are the symptoms of Migraine?

The most common sign of migraine is a headache lasting for hours or days. Symptoms generally include:

  • Pounding pain on one side of your head (or steady pain on both sides of the head).
  • Sensitivity to light and sound.
  • Nausea, vomiting.
  • Visual symptoms (usually in both eyes but often to one side) with some of the following characteristics:
    • A spot of blurring that expands to one side over 10-30 minutes.
    • An expanding border often described as zig-zag lines, ‘shimmering’ or resembling ‘heat waves’ or ‘sparklers’.
    • Vision loss in one eye only, involving the entire field or only the upper or lower section.

Rare symptoms include double vision, change in lid position or change in pupil size. In very rare cases, the visual problems with migraine may not entirely resolve. This may be due to a stroke associated with migraine.

3] How is Migraine treated?

Treatment usually first involves avoiding factors known to precipitate a migraine attack, such as foods, environmental triggers such as perfume and medication such as birth control pills. Aspirin and Ibuprofen etc may reduce the severity of an attack and are more effective if taken with some caffeine. There are some very effective prescription medications that deal with the chemical imbalances of migraine (including Imigran, Naramig ... ).

If the migraine attacks are severe or frequent enough, medication may be required on a regular basis (prophylactic). The most commonly used prophylactic medication groups are tricyclics, beta-blockers, calcium channel blockers and some anti-seizure medications.

How could I be having a migraine when I do not have a headache?

While headache is the most common symptom, visual symptoms and even neurological dysfunction may occur without a headache. The important features are the frequent repetitive nature of the events and most importantly the transient nature with no evidence of residual dysfunction. While migraine can lead to a stroke this is rare and all of these patients deserve a work up to make sure nothing else is going on.

Do I have to take these medications?

No. The medications are designed to either relieve symptoms during an attack or decrease the frequency of attacks. If the symptoms are not bad, the episodes occur infrequently, or they respond to ‘over-the-counter’ pain medications it is not necessary to take anything.

Disclaimer: Adapted from Nanos