Endometriosis: the consequence of neurological dysfunction?

Endometriosis describes endometrium found outside the uterine cavity and is frequently associated with clinical presentations of chronic pelvic pain, dysmenorrhoea, dyspareunia and subfertility. It was originally attributed to retrograde menstruation with endometrium passing in a reverse direction along the Fallopian tubes into the peritoneal cavity though this theory does not account for the spectrum of intrapelvic findings. Denervation followed by reinnervation in the uterine isthmus is proposed as the primary source of clinical symptoms, and, retrograde menstruation with adhesion of endometrium to injured tissue surfaces the variable laparoscopic findings. Primary sources of denervation are difficult intrapartum episodes (parous women) and persistent straining to achieve defaecation (nulliparous women). Progressive reinnervation including stromal nerve fibre proliferation, microneuroma formation and periarterial nerve fibre proliferation, takes place over five to ten years. Damage to uterine innervation interrupts normal patterns of uterine contractility, causing loss of fundocervical polarity which promotes retrograde menstruation. Ectopic endometrium may be a marker for prior tissue damage and does not contribute to the clinical symptoms--the disease may have been largely defined by an epiphenomenon.