14 Conditions Endometriosis Is Mistaken for the Most

This painful disease hits 1 in 10 women—yet it’s tough to diagnose because it shares symptoms with so many other conditions.

Know what endometriosis is

Each month, a woman sheds the endometrial lining in her uterus and regrows a new lining. However, in about 10 percent of reproductive-age women, this endometrial tissue also grows outside the uterus—a condition known as endometriosis. The wayward tissue doesn’t break down and shed as it would in the uterus; instead, it triggers inflammation and immense pain. “These endometrial growths have been found on the ovaries, fallopian tubes, bladder, on the outside of the uterus, lining the pelvic cavity, and between the vagina and rectum. In rare occasions, growths have been found in the arm, thigh, and lung,” says John Rapisarda, MD, a reproductive endocrinologist with Fertility Centers of Illinois.

Who gets endometriosis?

Though there’s no one cause of endometriosis, Dr. Rapisarda explains that risk factors include infertility, starting menstruation earlier, experiencing menopause later, shortened menstrual cycles, elevated levels of estrogen in the body, smoking, having a low body mass index, and uterine abnormalities. “Those with a close relative who has endometriosis, such as a mother, aunt, or sister, are at a higher risk of being diagnosed with endometriosis.” Endometriosis doesn’t just happen to adult women either; it’s been found in girls as young as eight years old.

Diagnosing the condition

The biggest challenge with endometriosis is how difficult it is to diagnose. In fact, according to the Endometriosis Foundation of America, it takes an average of ten years from the onset of symptoms for women to get an accurate diagnosis. This is partly due to a lack of knowledge about the condition among women and the medical community. Another issue is that the symptoms can be similar to other gastrointestinal and gynecologic diseases. Following are some of the most common conditions that endometriosis may be mistaken for by doctors.

Primary dysmenorrhea

Extremely painful menstrual cramps—dysmenorrhea—are one of the most widely recognized symptoms of endometriosis, according to Ken Sinervo, MD, OBGYN, of the Center for Endometriosis in Atlanta, Georgia. However, it is possible to suffer from menstrual pain without a specific pelvic abnormality. This is called primary dysmenorrhea and it’s among the most common of gynecological disorders. “Generally characterized by menstrual cramping, dysmenorrhea may also be accompanied by other symptoms such as sweating, headache, nausea, vomiting, or diarrhea, and they occur just before or during menses in individuals with normal pelvic anatomy,” says Dr. Sinervo. “Pain associated with typical or ‘primary dysmenorrhea’ can typically be treated with over the counter remedies or medications, whereas severe dysmenorrhea failing to respond to medical therapy, or ‘secondary dysmenorrhea,’ is typically associated with endometriosis and warrants proper diagnosis and treatment.”

Adenomyosis

This benign uterine disorder shares many symptoms with endometriosis—pelvic pain and infertility along with heavy or lengthy, painful periods that include bloating. However, adenomyosis is quite different in how it presents itself internally, according to Dr. Sinervo. Instead of endometrial tissue growing outside of the womb, he says, with adenomyosis, endometrial glands and fluids are found in the middle lining of the uterus,” he says. Diagnosis is also tough with this disease—imaging can help, he says, but often surgery is necessary to establish adenomyosis. Often, hysterectomy is the only cure.

Fibroids

These common benign tumors in the uterus are known as leiomyomas or myomas; they can cause abnormally painful periods. In fact, the intensity and character of pain caused by fibroids are quite similar to that of endometriosis. When women have painful menses along with pain during sex and uncomfortable bowel movements, endometriosis may be most likely, explains Aaron Styer, MD, a reproductive endocrinologist, founding partner, and co-medical director of CCRM Boston. “A pelvic ultrasound can be performed to evaluate a woman for fibroids,” he says; if fibroids are ruled out, endometriosis may be the most likely cause of the symptoms.

Ovarian cysts

These common, usually benign growths in the ovary come in all different sizes and varieties. While most go away without any medical intervention, some may cause severe pain if they are large or they rupture, explains Anate Brauer, MD, a reproductive endocrinologist at the Greenwich Fertility and IVF Centers and assistant professor of OB/GYN at NYU School of Medicine.

Sometimes cysts on an ultrasound can be mistaken for endometriosis, says Dr. Brauer: “An ovarian cyst can be composed of endometriosis—this specific type of cyst is called an endometrioma—but a simple ovarian cyst tends to go away after four to eight weeks,” she says. “Endometriosis, on the other hand, persists, so if you’re suffering from what you think is an ovarian cyst that won’t quit, consult your doctor about additional imaging such as an MRI.”

Pelvic Adhesions

Any scarring in the pelvis or abdomen—often due to an infection or prior surgery—can be misdiagnosed as endometriosis itself, according to Dr. Brauer. “Presence of pelvic adhesions can cause significant chronic pelvic pain that is similar to that experienced with endometriosis. However, it’s not as closely linked to the timing of your menstrual cycle as is in the case of endometriosis,” she says. If you have pelvic pain, here’s what it could mean.

Fibromyalgia

This chronic pain disorder is notoriously difficult to diagnose. Patients generally have symptoms like muscle and joint pain as well as pelvic pain—and together, they can be mistaken for endometriosis, explains Dr. Brauer. (Or the other way around: Endometriosis can be diagnosed as fibromyalgia.) “The general treatment for fibromyalgia involves pain medications or neuromodulators,” she says.

Appendicitis

This little finger-shaped pouch hangs off your colon on the right of your abdomen. “It may have a function as part of the immune system before the ages of seven or eight,” says Dr. Sinervo, “and it may serve as a reservoir for healthy bacteria.” But as you get older, the organ is mostly known for becoming infected and inflamed, leading to excruciating pain in your belly. Appendicitis can share many of the same symptoms as endometriosis, including right-sided lower abdominal pain, pain that worsens when you’re walking or moving around, nausea, vomiting, constipation or diarrhea, and bloating. Unlike endometriosis, says Dr. Sinervo, appendicitis is usually accompanied by a fever and can be diagnosed by CT scans and elevated white blood cell counts.

Gastrointestinal issues

Disorders such as irritable bowel syndrome (IBS), colitis, and diverticulosis may trigger symptoms similar to those from endometeriosis—abdominal bloating, alternating periods of diarrhea and constipation, and painful bowel movements. “Since endometriosis may implant on the intestines and cause irritation, women with this disorder may have symptoms that are similar,” says Dr. Styer. For this reason, it can be difficult to differentiate between endometriosis and gastrointestinal disorders.

Urinary tract infection (UTI)

Most women know the symptoms of a UTI—pain during urination or sex. That’s why women with endometriosis are often given treatment for UTIs, explains Dr. Rapisarda. “A simple test for infection will show whether a UTI is present and antibiotics are necessary,” he says. “If symptoms persist, but an infection is not present, further testing and analysis should be done by a medical professional.”

Pelvic inflammatory disease (PID)

This inflammation results from an infection of the reproductive tract—typically the uterine lining, fallopian tubes, ovaries, and pelvic peritoneum, explains Dr. Sinervo. “Though PID may spread silently, it can also be extremely painful and be accompanied by symptoms such as pelvic or lower abdominal pain of varying severity, intermenstrual bleeding, painful sex or painful urination—also common to endometriosis,” he says. “Unlike endometriosis, however, which is not an infection, PID is generally diagnosed through exams and cultures and routinely treated through administration of medication.

Sciatica

The sciatic nerve runs from your lower back down each leg, and when inflammation in your lower back pain presses on the nerve, the sensations can travel to the pelvis and the legs. Though sciatica is nothing like endometriosis, its pain symptoms in the back, buttocks, and legs can lead to confusion for patients and their docs. “With endometriosis, tissue can grow on nerves in the pelvis, causing back and leg pain that can be confused with sciatica,” explains Dr. Rapisarda. “An X-ray or MRI is typically required to help determine whether anything along the spine is causing pain, which will allow a physician to better assess the cause.”

Polycystic ovarian syndrome (PCOS)

Endometriosis and PCOS have a lot of overlap in the symptom department—in addition to the fact that both conditions tend to go undiagnosed for years. “Women with PCOS may have intermittent pelvic pain associated with the rupture of a cyst; they may get abnormal bleeding and cramping from excessive buildup of the uterine lining due to infrequent or absent ovulation,” explains Dr. Rapisarda. “A diagnosis of PCOS is based on the results of a physical exam, ultrasound and blood tests.”

Pelvic floor dysfunction

Also known as PFD, this common condition can turn up in endometriosis patients—though not all patients with PFD have endometriosis. The muscles of the pelvic floor don’t do their job—the reason may be an injury or difficult childbirth, though the cause isn’t always clear. The main symptoms can be urinary or bowel troubles (incontinence or difficulty going), though there are other symptoms similar to pelvic endometriosis, says Dr. Sinervo. “Effective treatment can be obtained under the care of a specially trained physical therapist; many patients with endometriosis are recommended for PT post-operatively to address this secondary source of pain after the disease is removed.”

Ectopic pregnancy

Approximately one in every 50 pregnancies in the United States is what’s known as an ectopic pregnancy—the egg implants outside the uterus. “Symptoms include acute (sudden) sharp or stabbing type pain in the pelvis—or even in the shoulder due to blood on the diaphragm from a ruptured ectopic—GI pain or symptoms, and vaginal bleeding,” says Dr. Sinervo. “Blood tests and ultrasound are used to diagnose an ectopic, unlike endometriosis, and medications or surgery may be used to resolve the condition.” He does note, however, that endometriosis may be a risk factor for ectopic pregnancy, along with infections, scarring, or defects in one or both tubes.