Botulinum Toxin for Pelvic Pain in Women With Endometriosis

Overview

Background: \- Some women with endometriosis have chronic pelvic pain. This pain may be caused by spasms of the pelvic floor muscles. These spasms can be detected by an examination. Studies suggest that botulinum toxin can help treat problems caused by muscle spasms. Researchers want to see if botulinum toxin injections into the pelvic floor muscles can decrease pain and spasms in women with pelvic pain. Objectives: \- To see if botulinum toxin can relieve pain from pelvic floor spasm in women with pelvic pain. Eligibility: \- Women between 18 and 50 years of age with pain associated with pelvic muscle spasm and endometriosis. Pain must be persistent (lasting for at least 3 months). Design: * Participants will keep a pain diary and record their pain medication use for a month before the first visit. * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. Participants will also answer questions about their pain levels and quality of life. * Participants will receive either botulinum toxin or a placebo (salt water) injection. The injection will be given into the pelvic floor muscles through the vaginal wall. Participants will take a muscle relaxant like Valium and have anesthetic cream put on the vaginal wall before the injection. * After the injection, participants will keep a pain diary for another month. * At a 1-month followup visit, participants will answer questions about their pain. If the pain has not improved, all participants may have a botulinum toxin injection (no placebo) into the pelvic floor muscles as before. * Participants will have followup visits for up to a year after the initial 1-month followup visit.

Chronic pelvic pain associated with endometriosis is poorly understood. Some women with chronic pelvic pain have muscle spasm of their pelvic muscles. Muscle spasm may be a significant part of pain in women with endometriosis and other types of chronic pelvic pain. Botulinum toxin injection is widely used to treat conditions associated with excessive muscle activity and spasm. Studies of botulinum toxin injected into pelvic muscles of women with pelvic pain have shown a decrease pain and spasm, but too few women have been studied to conclude its effectiveness. We expect to show that botulinum toxin injection in women with pelvic pain will relieve some of their pelvic pain. Eligible subjects will be otherwise healthy women who have chronic pelvic pain and a history of endometriosis. Subjects will be randomized to either botulinum toxin injection or placebo (salt water) injection. After one month, we will evaluate the presence of the pain and all women will be offered botulinum toxin injection. We will also evaluate the need for reinjection.