Sudden onset of abdominal pain indicates an acute abdomen, which could be appendicitis, ruptured ectopic pregnancy, acute ovarian torsion, ureteral calculi, etc. In the early stage of inflammation, there may be vague pain and distension in the upper abdomen or around the navel, and the pain may shift to the right lower abdomen and become worse in nature. Urinary stones and ureteral stones can also manifest as sudden onset of pain and colic in the lower abdomen, and can radiate to the perineum. If a female patient has a history of sexual intercourse and menopause, she may have a ruptured ectopic pregnancy and may have sudden lower abdominal pain that may radiate to the lower back.