A 30-year-old lady has a history of migraine that usually presents with a visual aura followed 5-10 minutes later by a severe right sided throbbing headache and photophobia. She usually manages these at home with analgesia and an oral triptan.
She presents to the ED at 4pm on your afternoon shift with a sudden onset of a severe headache that is of a different quality to her usual migraine and that was not preceded by any visual changes. She is convinced that she needs to have parenteral sumitriptan that she has required one time previously and that she will be fine after lying in a dark room for a few hours.
What are the most important historical features in determining whether the headache requires to be investigated for ?SAH in a neurologically intact patient.