MSRA-2458

A 30-year-old female patient presents to the Emergency Department with a 7-day history of lower abdominal pain. She describes the pain as all over the lower abdomen. On further questioning, she reports having noticed a small amount of odorous vaginal discharge, urinary frequency and pain on urination. Her basic observations include heart rate 98 beats/minute, respiratory rate 18 breaths/minute, blood pressure 110/65 mmHg, temperature 38.5 °C. On examination, there is diffuse tenderness of the suprapubic region, right iliac fossa and bilateral lower back.

What is the most likely diagnosis?