Endometriosis is a chronic condition where tissue similar to the lining of the uterus grows outside the uterine cavity, most often appearing on organs within the pelvic area, such as the ovaries, fallopian tubes, and the outer surface of the uterus. While primarily known for causing severe pelvic pain and painful, heavy periods, endometriosis can also cause discomfort in areas beyond the pelvis. Leg pain is a real and often overlooked symptom, affecting up to half of individuals diagnosed. This pain arises because the abnormal tissue growth and resulting inflammation can irritate or press on major nerves that run from the pelvis into the lower limbs.
Endometriosis and Referred Leg Pain
Leg discomfort can involve referred pain, which is felt in a location different from its source. Chronic inflammation and the development of scar tissue, or adhesions, within the pelvis create generalized tension and pressure. This irritation of the pelvic lining sends signals to the central nervous system, which may interpret the pain as originating in the hip, buttocks, or upper leg.
Constant pelvic pain can also lead to chronic muscle guarding and tension in the pelvic floor and hip muscles. Sustained tightness in these stabilizing muscles can put pressure on nearby nerves, creating an aching, deep throbbing, or stiffness that radiates down the legs. This type of leg pain is a common manifestation of overall pelvic inflammation, often presenting as a heaviness or warm feeling that can affect one or both legs.
Sciatic Nerve Involvement
A more specific cause of leg pain is sciatic endometriosis, which involves the sciatic nerve. This condition occurs when deep infiltrating lesions implant directly on or near the nerve or the sacral plexus, the network of nerves that forms the sciatic nerve. The sciatic nerve originates in the lower back, travels through the buttock, and extends down the back of the leg to the foot.
The implanted tissue is hormonally responsive and bleeds during the menstrual cycle. When this tissue swells and bleeds near the nerve, it causes direct irritation, inflammation, and compression. This cyclical process often causes the leg pain to begin or worsen significantly just before or during menstruation. Recurring inflammation can eventually lead to fibrosis and scarring around the nerve, potentially causing the pain to become chronic and constant.
Identifying Nerve-Related Symptoms
Pain caused by direct sciatic nerve involvement is distinct from general referred aches and mimics classic sciatica. Patients describe the sensation as a sharp, shooting, or electric pain that radiates from the buttock down the back of the leg, following the distribution of the irritated nerve. Beyond pain, nerve compression can result in specific sensory and motor deficits.
Symptoms may include paresthesia, a sensation of numbness, tingling, or “pins and needles” in the lower body. In severe cases, motor function can be affected, leading to leg weakness, difficulty walking, or foot drop, where the individual is unable to lift the front part of their foot. Recognizing these neurological symptoms points toward a serious form of nerve infiltration requiring focused intervention.
Seeking Diagnosis and Relief
If leg pain is cyclical, severe, and accompanied by neurological symptoms, consult a specialist, such as an endometriosis excision surgeon or a neuropelveologist. Diagnosis can be challenging because symptoms often resemble musculoskeletal issues, and routine pelvic exams may appear normal. Specialized imaging, such as high-resolution pelvic Magnetic Resonance Imaging (MRI), is used to visualize deep pelvic structures and check for lesions near the sacral plexus and sciatic nerve.
Treatment aims to remove the tissue causing nerve compression and manage inflammation. Hormonal therapies, such as birth control pills or progestins, may be prescribed to suppress the cyclical bleeding of the implants and offer pain relief. However, the most effective treatment for deep infiltrating endometriosis involving the sciatic nerve is often surgical excision. This specialized laparoscopic surgery must be performed by a surgeon experienced in complex cases to carefully remove the tissue, minimizing the risk of nerve damage and preventing progression toward neurological deficits.