A 21-year-old previously healthy woman presents with abdominal pain of 48-hour d

A 21-year-old previously healthy woman presents with abdominal pain of 48-hour duration. The pain was initially periumbilical and on progression became localized in the right lower quadrant. The woman had nausea and a decreased appetite. She denied dysuria. Her last menstrual period was 2 weeks earlier. On examination, she was febrile (temperature 38.2°C), and was found to have localized tenderness in the right lower quadrant with guarding. Rectal examination was normal. Laboratory examination demonstrated mild leukocytosis
What is the most likely diagnosis?
What is the pathogenesis of this condition?
What conditions should be included in the differential diagnosis?
What are the investigations in this condition ?
What is the most appropriate treatment for this condition?