A 22 year old lady presents with intermittent pain in the right lower abdomen for 2 days, with sudden worsening over the last 4 hours. She also experienced mild fever, nausea and vomiting. Her medical and drug histories are unremarkable.

She is nulliparous, with irregular menstrual cycles. Her last period was 7 weeks ago. She has not been sexually active for the last year and has no history of sexually transmitted disease (STDs).