How Does Endometriosis Cause Leg Pain?

Many patients experience pain in their legs and hips among their endometriosis symptoms. A variety of factors contribute to this, and  patients can experience leg pain due to one or several of these factors even if the problem is not in their leg or even directly on the nerves travelling to the leg.

One common way we see leg pain from endometriosis comes from something called “referred pain.”   Referred pain occurs when the trigger for the pain is located in a different part of the body from where the patient actually experiences that pain. A variety of different things can cause referred pain, including irritation of nerves as they pass through the area where the trigger is located, muscle and nerve dysfunction related to the trigger of the pain, or what we consider to be a case of “mixed signals” which occurs when the body is experiencing pain in an area that, because pain isn’t typically generated in that place, the pain signal is interpreted by the body as being in a different location.  A classic example of “referred pain” is when pain in the hip is actually being caused by a trigger located on the pelvic sidewall or sometimes in or on the ovary.  This can be diagnostically challenging because not all hip pain is caused by something going on inside of the pelvis, but in some cases this is how the body will interpret pain in the ovary or pelvis. 

Another potential source of leg pain comes from the fact that endometriosis can trigger severe pelvic floor dysfunction.  When a high degree of tension is placed on the many muscles of the pelvic floor, this can put pressure on the nerves that travel through the pelvis to the leg. That degree of tension adds up over time and can cause a severe pain that often shoots down the back of the leg, often manifesting as what patients will describe as a sciatica-type pain. While endometriosis is the trigger for this pain, and therefore does need to be removed in order to gain long-term relief, physical therapy is often also an integral part of treatment for this type of pain because significant work is required to undo the long-term tension of the pelvic floor that was imposed over many years by endometriosis. 

The least common but most challenging type of leg pain caused by endometriosis is when the endometriosis directly invades the major nerves that travel to the leg through the pelvis. This can happen with any of the major nerves including the sciatic nerve, the pudendal nerve and the obturator nerve. The sciatic nerve is the most commonly discussed of these because of its hallmark, which is severe radiating posterior leg pain that is unrelenting and unresponsive to medications or physical therapy. The good news is that this type of endometriosis can generally be seen on imaging due to its invasive nature, and therefore an expert team can make preparations to address and manage this very complex, though rare, manifestation of endometriosis. (This blog post was written by Washington Endometriosis & Complex Surgery, Washington DC)