What is the value of considering noninvasive methods for the diagnosis of endometriosis?
Dr. Flores: There is great value in noninvasive diagnostics for endometriosis. This is because while surgical diagnosis is the “gold standard,” surgery is invasive, and waiting until a surgical diagnosis can be made further contributes to delays in diagnosis. However, more recently there has been a shift toward utilizing noninvasive approaches to the diagnosis of endometriosis, with the primary one focusing on clinically diagnosing endometriosis.
One of the first things to remember is the importance of gathering a patient history and conducting a physical exam. We've all learned this in medical school, and it comes into play even more so with a condition such as endometriosis. Endometriosis is defined as a benign gynecologic disease characterized by endometrial-like tissue outside of the uterus, but this definition does not reflect the true scope and manifestations of endometriosis. Research over the years has demonstrated that endometriosis has systemic effects—affecting regions of the brain associated with anxiety/depression, altering pain sensitization, and having inflammatory effects that can not only affect the reproductive organs but also other organ systems. As such, our questions when evaluating patients for endometriosis need to focus on these various aspects of the disease.
Endometriosis usually leads to cyclic pain. This is because just as the lining of the uterus (the endometrium) grows and sheds every month in response to hormones, endometriotic lesions—which are endometrial-like tissue outside of the uterus—also grow and shed each month. However, there is no outflow for this shed tissue and, as a result, there is an inflammatory response as well as pain. Depending on where those lesions implant, symptoms can include not only cyclic pelvic pain but also cyclic bowel/bladder pain. I’ve also had patients complain of cyclic sharp/shooting leg pain.
Many times, patients present to us after having seen several different types of providers and having been diagnosed with conditions such as irritable bowel syndrome or painful bladder syndrome. However, if you talk to patients and ask them to tell you a little bit more about this bowel or bladder pain, they will frequently endorse that their symptoms are cyclic/most severe during their menses. With respect to pelvic pain, endometriosis-related pelvic pain is usually progressive—becoming progressively more painful over the years. These symptoms are strong indicators that endometriosis is the cause. A pelvic exam is also helpful as findings of nodularity or a fixed uterus may lend further support for endometriosis; a normal exam, however, does not rule out endometriosis.
What are the primary imaging techniques used to diagnose endometriosis?
Dr. Flores: While history and physical exam are the primary components of the clinical diagnosis, imaging can also be helpful. The 2 techniques most often used are pelvic ultrasound and magnetic resonance imaging (MRI).
While transvaginal ultrasound is sensitive and specific for diagnosing endometriomas (ovarian cysts of endometriotic tissue) and may also be able to accurately identify deep-infiltrating endometriosis, it is limited in its ability to visualize peritoneal disease. MRI can improve diagnosis of endometriosis and better estimate the depth of invasion of deep-infiltrating disease, as well as confirm diagnosis of an endometrioma. While MRI is an option for peritoneal endometriosis, superficial disease is usually not detected. Lastly, computed tomography imaging of the chest can be used when thoracic endometriosis is suspected but is otherwise not routinely recommended. Imaging is also helpful in ruling in/out other potential etiologies of pelvic pain such as fibroids and adenomyosis. It is important to recognize, however, that the absence of any findings of endometriosis on imaging does not rule out the disease.