Catherine, a 32-year-old woman, presents with gradually worsening pelvic and abdominal pain.

She was diagnosed with endometriosis three years previously, and underwent laparoscopic treatment with significant improvement in dysmenorrhoea.

However, she has had ongoing intermittent episodes of pelvic and abdominal pain, unrelated to her menstrual cycle.

These have been worsening in recent months and are associated with bloating, flatulence and lethargy.