Although most women are all too familiar with cramping and bloating, women with endometriosis tend to experience pain that can interfere with their relationships and everyday activities. Endometriosis is a curious gynecological condition that occurs when cells that normally line the inside of the uterus break away and seed somewhere else in the body where they don't belong—sometimes as far away as the lungs. It can cause severe menstrual cramps and infertility as well as debilitating pain and may explain a host of nebulous complaints.

It's estimated that 5.5 million women in North America have endometriosis, but it's difficult to assess how common the condition truly is because surgery is required for a definitive diagnosis. While some women and their doctors choose to manage the condition with hormones without a confirmed diagnosis, others opt for the surgery.

Below, Tommaso Falcone, MD, chairman of obstetrics and gynecology at the Cleveland Clinic Foundation in Ohio, explains endometriosis symptoms and reviews current diagnostic tests and treatments, as well as the research devoted to finding an effective non-surgical way to diagnosis this disease.

What is endometriosis?
Endometriosis is defined as the presence of endometrial tissue, which is the tissue that is found on the lining of the uterus, outside of the uterus.

What are some common and uncommon locations for this tissue?
The common locations are the ovaries and the inside of the vagina in the so-called the cul-de-sac, which is the area of the deepest part of the pelvis, and the lining of the pelvis called the peritoneum.

There are circumstances where it is found at other sites. The most common area outside of the pelvis would be the intestine. It could be on the appendix, the liver or the lung. It's located on nerves such as the sciatic nerve, which is that big nerve in the leg. It's been reported pretty much everywhere in the body.

Patients will have different types of symptoms depending upon the location of the tissue. For example, if it involves the sciatic nerve, the patient can have leg pain and difficulties walking. Or if they have endometriosis on the intestine, they'll have intestinal symptoms, like constipation or diarrhea. If it's on the lung, they may go to a lung specialist with a collapsed lung. Then after they've had a biopsy, they wind up seeing a gynecologist.

What are the most common symptoms?
The most important symptom is pain, and then infertility. The pain part is usually very bad pain before or after the period and with sexual intercourse. Women may also have non-cyclic pelvic pain, which means it can come at any time.

Then there's a whole myriad of other symptoms such as diarrhea or constipation and urinary symptoms such as pain when urinating, though those symptoms could be due to a lot of other things, too.

Does the tissue respond to the hormonal changes of the menstrual cycle?
The lining of the uterus responds to estrogen/progesterone, so this tissue will also respond to variations in estrogen and progesterone levels or the lack of estrogen and progesterone. The degree of the response may differ from patient to patient and by location. These hormones are the basis of some of the things that we use as treatment, such as the birth control pill; other times we remove hormones like estrogens with drugs that induce menopause.

Although there are differences between the hormonal receptors in the endometrium and the receptors in the endometrial tissue that is found elsewhere, endometrial tissue outside of the endometrium will still respond to hormonal changes.

Why does scarring form and what are the consequences of it?
Scarring forms in endometriosis patients as a result of the chronic inflammation. The scarring that involves structures like the vagina is deeply infiltrating and may involve nerve endings. This causes pain. If extensive, the uterus becomes immobile and fixed in place, and this can make sexual intercourse very painful. The extensive scarring can involve the fallopian tube and ovaries and impair the process by which the tube picks up the egg from the ovary. This can cause infertility.

Also, scar tissue may not respond to the hormonal therapies or to a woman's hormonal changes.

Is endometriosis often mistaken for other conditions?
If women have a lot of bowel symptoms, then it's confused with irritable bowel syndrome, which is a common problem in women and men. It can be confused with interstitial cystitis, which is an inflammation of the bladder. If someone has pain, you also have to think of nerve pain, which can be due to a hernia or an entrapped nerve or some musculoskeletal problem of the interior abdomen. So if a woman has pain of the lower abdomen, you have to go through this careful history and physical examination.

What is the first step in diagnosing endometriosis?
For the moment, the only true and standard way to make the diagnosis of endometriosis is by taking a sample piece of tissue during a surgical procedure called a laparoscopy.

How is the condition treated?
Most of the time, we just treat the endometriosis without the surgery. If someone says, "I have bad periods," then you say, "Well, look, if I do surgery, there's risks. Why don't you take some ibuprofen?" And if the ibuprofen works, fine. The next step is to try the birth control pill.

After you've tried the Pill and ibuprofen and it still doesn't work, the woman might have a laparoscopy. Alternatively, a doctor can continue to treat this condition with more intense treatments without a clear diagnosis and that's where the medical community has a debate about what you do. The purist will say, "Look, we don't have a diagnosis so we'll do a laparoscopy, take a piece of tissue, confirm it and then we'll treat one way or the other." The other approach is more practical. People say, "Treat them with the next level of hormones."

These drugs render the woman temporarily menopausal. Some women think that's the best thing that ever happened to them and other women feel that it's the worst thing that's ever happened to them. Women on these medications can have headaches and hot flashes, and some women have reported memory loss and osteoporosis.

There are also male hormone-type drugs like danazol. Most patients don't like them, however, because they can gain weight and add some facial or body hair growth.

What is laparoscopy?
Laparoscopy is the current gold standard for diagnosis because it's a visual diagnosis. Laparoscopy is a surgical procedure usually performed under anesthesia. We put a small camera that can range from 3 mm to 5 mm in the umbilicus, and we then have a good view of the ovaries and tubes and uterus. When you look at the tissue with your eyes, you say, "Ah, there it is." But you need a pathologist's confirmation before you're diagnosed with endometriosis. The pathologist looks at the cells to make sure it is not cancer or something of that nature because endometriosis can be associated with certain cancers.

If we find endometriosis, it can be surgically treated at that time.

How are women usually treated during a surgical procedure?
Typically we'll say, "Oh, yeah, this looks like classical endometriosis. Let's treat it." What the doctor will then do is take some energy form, a laser or something of that nature, and destroy the tissue. The more advanced the disease, the more difficult it is simply to burn it. So the doctor might have to remove the tissue surgically.

Are there non-surgical tests for endometriosis?
Research is ongoing to find the so-called nonsurgical diagnostic test for endometriosis. Imaging techniques such as transvaginal ultrasound and MRI have a good sensitivity when patients have cysts. (Sensitivity means the ability to pick up the disease when the disease is there.) However, the majority of patients with endometriosis do not have cysts. Then ultrasound and MRI are of little value. So most of the time, you will miss the disease.

Finally, if you look at ultrasound versus MRI, MRI does not add anything over the transvaginal ultrasound. And the cost is far higher. So, in clinical practice, we do not use MRI very often, unless we suspect some abnormality like sciatic nerve involvement.

Then we can look at the CA125 blood test. Again, the sensitivity is very poor unless you have advanced endometriosis.

Ideally, it would be good to find a marker that you could do a test blood for that would indicate someone has endometriosis. At the Cleveland Clinic we're looking at cytokines, which are chemical mediators secreted by some types of white blood cells. In patients with endometriosis, there is an increased immune response, both in the cavity where the uterus and ovaries are, and in the blood. Some of the preliminary results shows that it may have a very high sensitivity, but we have to confirm it with further clinical trials. And we are also looking at gene markers that are only found in endometriosis patients.

Are there any myths about endometriosis?
One myth is that most patients with endometriosis have infertility. In reality, most patients with endometriosis have pain. The big myth is that if you get pregnant your endometriosis will go away. It's very commonly suggested as a form of treatment, which, of course, is ridiculous in itself, and it's not a treatment. So the patients can get pregnant and still come back with pain, for example.