Ms Rose is admitted with severe throbbing unilateral cephalgia that has lasted for 2 days. Light makes her cringe and she complains of nausea. Before the onset of these symptoms, she saw zig-zag lines for about 20 minutes. Diagnosis was acute migrane. A vasoconstrictor is prescribed and Ms Rose's condition is Migraine headaches are thought to be caused by sudden dilation of blood vessels.