Endometriosis-Like Syndrome: From the Concept of Painful Uterine Syndrome to the use of Myometrial Botulinum Toxin Injections under Hysteroscopy

Abstract

Background: A new concept is being advanced to explain undiagnosed chronic pelvic pain, severe dysmenorrhoea, painful uterine contractions, and deep dyspareunia in women, which has been shown to be anatomically negative. Search strategy: In these "endometriosis-like" syndrome situations, there are many pathophysiological arguments supporting the existence of a visceral uterine sensitization syndrome. Data collection and analysis: These arguments are further developed and use central sensitization mechanisms, just like those for irritable bowel syndrome (IBS) or painful bladder syndrome (PBS). The name "painful uterine syndrome" (PUS) has been suggested, and a basis for a PUS diagnostic score has been established. Central sensitization and visceral sensitization mechanisms have been developed. Muscular hypertonia is common in condition of central sensitization and increased uterine contractility has been confirmed using cine magnetic resonance imaging in PUS situations. These findings led to the application of botulinum toxin (BTX) injections under hysteroscopy of the uterine myometrium in PUS. Main results: A significant amount of physio-pathological evidence supports the existence of visceral uterine sensitization syndrome. We call it Painful Uterine Syndrome (PUS). A pilot study reported the first use of BTX uterine injections under hysteroscopy in PUS and this pilot study, previously presented, has been analysed. It focuses on a simple and reproducible treatment procedure which shows improvement in dysmenorrhoea and dyspareunia as well as improved quality of life scores. Conclusions: PUS should be consider as one main mechanim for Chronic Pelvic Pain. Uterine BTX injection could be a very interesting therapeutic option. Only long-term randomised studies will be able to confirm that BTX injections are useful as a treatment for this condition. The randomised long-term study, Uteroxine, started in 2020 and will shortly release its results.