Lena Dunham says she has endometriosis - here's what the condition is

Actress, writer, and director Lena Dunham, of "Girls" fame, publicly announced this week on Instagram that she has endometriosis - a painful and chronic condition. 

"I just wanted to let you know that, while I am so excited for Girls to return on Feb 21, I won't be out and about doing press for the new season," Dunham wrote in the Instagram post.
"As many of you know I have endometriosis."

Endometriosis is a condition that affects women and refers to when tissue that would normally line the uterus instead grows outside of the uterus, sometimes cropping up on the ovaries, behind the uterus, or on the bowels or bladder (though it can also grow on the nose, lungs, arms and legs).

It affects 6.3 million women and girls in the U.S. alone - about 1 in 10 women of reproductive age.

Like the normal lining of the uterus, the excess tissue thickens, breaks down and bleeds each menstrual cycle. But since it has no way to flush itself out of the body, it gets stuck, and can form ovarian cysts or irritated tissue that hardens around the organs.

As Vox reports, the condition is really hard to diagnose. It involves a surgical procedure called a laparoscopy, in which doctors make a small cut in the stomach and insert a tiny camera to look for scar tissue on the pelvic organs.

The most common symptoms include pain in the abdomen, lower back, or pelvis, especially during menstrual cramps, during or after sex, or during bowel movements or urination; infertility; and heavy periods.

Other symptoms include fatigue, diarrhea, constipation or nausea. Some women do not have any symptoms at all. Dunham, however, isn't one.

While Dunham didn't describe the specifics, she reported that she's going through a difficult time with the disorder:

"I am currently going through a rough patch with the illness and my body (along with my amazing doctors) let me know, in no uncertain terms, that it's time to rest," she wrote. 

Cause is not completely understood

The causes of endometriosis are not completely understood, but it may result from something called retrograde menstruation, where menstrual blood flows back up the fallopian tubes instead of out of the body.

Another possible cause is if immature cells in the abdominal lining turn into endometrial tissue (uterine tissue outside the uterus). Yet another possible cause can be from surgery or from to an immune system failure.

The condition runs in families, so there may be a genetic component.

There is no cure for endometriosis, but it can be treated with medications and surgery.

Doctors may recommend over-the-counter pain meds like ibuprofen or naproxen. Hormonal therapy (in the form of pills, patches, or injections) may slow the growth of new endometrial tissue.

Finally, surgery is an option to remove some of the endometrial tissue without damaging the reproductive organs, or patients can have a complete hysterectomy.