Diagnosis of acute appendicitis

Ms. F, 48 years old, has been admitted to the hospital with severe abdominal pain. Earlier that day she had generalized abdominal pain, followed by a severe pain in the lower right quadrant of her abdomen, accompanied by nausea and vomiting. That evening she was feeling slightly improved and the pain seemed to subside somewhat. Later that night, severe, steady abdominal pain developed, with vomiting. A friend took her to the hospital, where examination demonstrated lower right quadrant tenderness and mild abdominal rigidity. Fever and leukocytosis indicated infection. A diagnosis of acute appendicitis, with possible perforation, was indicated, with immediate surgery.

Why is the sequence of pain (location and type of pain) significant in the diagnosis of acute appendicitis? Describe the rational for each type of pain. Does this sequence confirm the diagnosis?