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New Treatments for Endometriosis

How do we approach looking for pain? It is a little different than even just looking for endometriosis. We can take the Cartesian theory, which says that we are really just going to look for the physical problems and we are not going to deal at all with the emotional or psychological aspects. This in particular does not work well with chronic pain patients, because there are always other things going on besides the pathology. One of the most interesting theories that came out in the 1970's was the gate control therapy which showed that even with discrete physical symptoms, peripheral signs such as pinches and things, when that information gets to the spinal cord, it can be significantly modified by local information and by sending endometrosis.

What is so interesting about visceral pain as compared to pain that may be from a discrete injury is that it is always very hard to pinpoint the cause. We know that the extent of disease with, for instance, endometriosis, does not correlate one to one with the pain of any particular patient. There are a whole lot of reasons for this. The fibers that are transmitting this visceral pain are smaller diameter fibers and they are less discretely localized. They usually have some graded response, so they are not just pain versus touch, like you get on the skin. In the rectum, for instance, they may tell you about stretch or they may tell you about pain, which gets translated into irritable bowel syndrome. The same thing is true in the ovary; you may have a sensation of endometreosis.

Recently, people have started to talk about doing localized spinal blocks to see if they can eliminate some of the signals from the pelvis. By that time, all the nerve elements have gotten there. Obviously, this is something an anesthesiologist or pain specialist would try. Even at the level of the spinal cord, all this information is going to be converging on particular neurons.

The other concept that people worry about is that patients who, for instance, have an appendicitis. They may have deep pain from this visceral organ. They often have these autonomic reflexes - sweating, nausea, vomiting - this goes along with visceral problems. But many patients have referred pain and that is when the pain may actually be from an ovary or may be from endometriosis, but it is not felt in the same way and it is localized.

The other problems that we worry about in any chronic pain syndrome, whether it be headaches, back pain or pelvic pain, are that once there is a loop of a pain signal going to the central nervous system, even when you take away the stimulus, sometimes the neuronal activity continues. This is called centralization. In that case, the patient thinks that the pain is still there, even when the peripheral signal is interrupted and the pain can even get worse with a variety of treatments.

Going back to the easier problem that we can deal with, that is the problem of dysmenorrhea. About twenty to thirty percent of women of reproductive age complain about this. These are the women who actually go the physician and complain about dysmenorrhea. This is approximately two to ten percent of gynecological visits in this country. If you really survey women, and there was a Gallup survey recently in the United States, in their 1994 survey, almost fifteen percent of women just randomly, who weren't seeking any attention, did complain of dysmenorrhea. Sixty percent of those women actually reduced their activity because of this pain. Only a fraction of those women actually sought a physician for care. Similarly, there have been a lot of studies of teenagers, since we know that this is much more common in adolescents, and there was a recent study in Australia where they actually asked high school seniors about symptoms and eighty to ninety percent of them said that they had pretty severe symptoms. Forty percent were missing time from school or sports activities. Twenty-five percent of the adolescents had no idea that there was any remedy that they could try.

When people looked at what the uterus is doing, they have been able to show that the contractions have a higher intensity in women who have the most severe complaints of dysmenorrhea. So there may be a correlation there. In primary dysmenorrhea, you are not going to find any pathology other than uterine contractions and you may find some of these associated symptoms. I think we all think that these symptoms are due to the prostaglandins.

One of the newer COX-2 inhibitors, Vioxx, did get an indication for dysmenorrhea, but it is quite expensive, so if a patient has failed other treatments or over-the-counter medications at higher doses, you might want to try it.

What about secondary dysmenorrhea? When do you have to look for causes? All that means is that you find something that is more than just menstrual cramping. You may find fibroids; people have suggested that polyps contribute to it, although the evidence is not as good; chronic infections; cervical stenosis; and certainly people who have IUD's in place. The other categories would include adenomyosis and endometriosis at the top of the list of the things that make this worse.

When do you need to look for this? Obviously, in the teenager, where most of these are less likely, you can assume it is primary dysmenorrhea and treat with non-steroidals. It is also helpful to treat with oral contraceptives, since decreased menstrual flow automatically decreases the prostaglandin production. If it is an older woman or you feel an enlarged uterus or they have infertility, then laparoscopy can be used to rule out endometriosis. You can use ultrasound to rule out the fibroids.

Even if you find something in a patient, such as a solitary fibroid, it doesn't mean that you can't get oral contraceptives and nonsteroidal anti-inflammatory drugs to work in that group of patients, it's just that you have another diagnosis that further down the line may require treatment.