Twenty-seven-year-old Marilyn comes to the emergency room at 10 am complaining of sudden periumbilical pain that radiates to the RLQ (right lower quadrant). She says that the pain started about 2 o'clock that morning and was not too bad but now is unbearable. Upon physical examination, Marilyn's oral temperature is elevated to 101F (38.3C). Her abdomen is rigid, and she has rebound tenderness in the periumbilical and RLQ regions.