(Portland, OR)  --  Police are searching for a missing Sherwood girl who might be in trouble in Portland.  They say 17-year-old Effie "Nikki" Shaha-Walberg has a seizure disorder and needs medicine for it.  Police say she unexpectedly left home this past Sunday evening and told a friend the next day she was in the downtown Portland area.  She's five-foot-two and 117 pounds, and was last seen wearing gray jeans, a black t-shirt and black shoes.