Clinical Reasoning: A 22-year-old man presenting with headache and right leg jerks.

A 22-year-old man with no pertinent medical history presented to our emergency department with headaches, nausea, vomiting, and right leg jerks. Two days prior, he developed a sudden-onset, throbbing headache that was 6/10 in severity involving his entire head. He denied photophobia/phonophobia or visual changes. He felt dizzy and lightheaded without room spinning. The next day, he noticed his right leg felt “heavy.” That evening, he had nausea and 2 episodes of emesis. The next morning, he awoke with insuppressible “twitches” in his entire right leg. These were not painful and occurred every few seconds at rest and with activity. No history of similar headaches, abnormal movements, trauma, seizures, sick contacts, or recent travel was noted. Family history was unremarkable. He had normal development, completed high school, and worked full-time installing solar panels.