A 35 year old woman with fibromyalgia and irritable bowel syndrome presents with 2 months of gradually worsening bladder pain, especially with a full bladder, relieved with voiding. The sensation varies from pressure and discomfort to painful spasms to severe debilitating pain. The pain is suprapubic and accompanied by urgency and frequency. There was no identifiable triggering event. This symptoms are worse with some foods, stress, and the menstrual cycle. There is no incontinence but she urinates up to 50 times a day to avoid pain. This has greatly affected her quality of life and ability to work. Examination shows tenderness of the abdominal wall, hip girdle, pelvic floor, bladder base, and urethra. The pelvic floor muscles are tight. Urinalysis is unremarkable and urine culture is negative. A post-void residual volume is normal. A cystoscopy shows reddened lesions on the bladder mucosa with attached fibrin deposits.
Challenge: What is your most likely diagnosis?