An acute migraine is a severe headache that comes on suddenly and often causes nausea, light sensitivity, and fatigue.Migraines may be triggered by one of a number of different factors, including alcohol withdrawal, intense light or sounds, stress, or hormonal imbalances.nce a migraine actually sets in, a person is likely to develop a throbbing, dull headache that may be accompanied by chills, weakness, vomiting, and sweating. Another form of migraine, called an acute confusional episode, is almost exclusively experienced by young children.