Overview

What is endometriosis?

Endometriosis is a chronic disease where tissue similar to the lining of the uterus grows in other places, commonly in the fallopian tubes and ovaries. 

During menstruation (periods), endometrial tissue (the inner lining of the uterus) sheds. However, with endometriosis, endometrial-like tissue forms on other structures, causing inflammation, ovarian cysts, superficial lesions, adhesions and scar tissues in the body.¹ 

Endometriosis is a long-term condition affecting those who menstruate of any age, from their first period through to menopause. In the UK, 10% of these individuals are affected with an average diagnosing time of 7.5 years. 

Endometriosis causes 

The exact causes of endometriosis are unclear. However, possible causes may include:

Retrograde menstruation

Menstrual blood containing endometrial cells flows back through the fallopian tubes, as blood flows through the cervix and vagina during periods. Endometrial cells can deposit outside the uterus where they implant and grow.

Cellular metaplasia

Cells outside of the uterus change into endometrial-like cells and begin to grow.

Stem cells

Endometriosis can arise due to stem cells and spread through the body via blood and lymphatic vessels.

Symptoms of endometriosis

Growth of endometrial-like tissue in foreign places can impact daily life due to the uncomfortable symptoms associated with the condition. Symptoms may include:²

• Pelvic pain during or after sex
• Pain whilst urinating 
• Heavy bleeding during or between periods 
• Painful menstrual cramps
• Bloating
• Difficulty getting pregnant 
• Depression or anxiety

Endometriosis can cause pain alongside several other complications, such as infertility. In this article, we will explore the diagnostic methods, management, and treatment options available to alleviate its symptoms and improve patient well-being. 

Diagnosis of endometriosis

Endometriosis is attributed to various symptoms that could be caused by other conditions, making it difficult to diagnose. Diagnosis can be made systematically by combining patient history, pelvic examination, imaging tests, and a laparoscopy for a more accurate identification. 

Clinical history

The first step in diagnosis is a clinical examination. Your doctor will establish your medical history, focusing particularly on symptoms, such as:³

• Chronic pelvic pain
• Dysmenorrhea (menstrual cramps)
• Dyspareunia (painful intercourse)

Other factors that may be assessed include:

• Menstrual history
• Family history of endometriosis
• Previous surgical and non-surgical treatment for endometriosis
• Infertility

A clinical examination alone is insufficient for diagnosis due to the poor relationship between patient symptoms and the severity of endometriosis. Additionally, 2% to 50% of patients may have asymptomatic endometriosis.³

Pelvic examination

A pelvic examination checks for unusual changes in your reproductive system, performed by a gynaecologist. 

It usually starts with abdominal palpation, where steady pressure is placed on the abdomen to assess pain, followed by examination of the outside of the vagina to check for irritation and inflammation.⁴  

This is followed by a bimanual pelvic examination, where two gloved fingers are inserted into the vagina and pressure is placed on the abdomen with the other hand. This examination is used to assess for changes, including:

• Cysts
• Painful spots
• Irregular growths called nodules
• Scars behind the uterus

Imaging tests

A clinical and pelvic examination detects only 50% of deep endometriotic lesions, therefore imaging is a favourable approach for diagnosis.⁵ 

Ultrasound

Transvaginal ultrasounds (TVS) are used in an endometriosis diagnosis. It involves inserting a probe into the vagina that causes sound waves to bounce off organs inside the pelvis. It is used to examine the vagina, uterus, fallopian tubes, ovaries, and bladder.⁴   

TVS can identify signs of the condition, such as:

• Endometriomas - Endometrial tissue that has formed into cysts in the ovaries.
• Deeply infiltrating endometriosis - Endometrial tissue that is deeply embedded in the bowel or bladder. These lesions typically grow 5 mm or deeper.

TVS cannot identify superficial endometriosis, the most common type of endometriosis. Superficial endometriosis includes lesions that are less than 5 mm on the surface of organs. 

Magnetic resonance imaging (MRI)

MRI uses a magnetic field and radio waves to produce images of organs and tissues in the body. 

The advantage of MRI compared to TVS is that it has a high contrast resolution to provide detailed information on the location and size of endometriosis growths.⁶ This tool can therefore aid presurgical planning if required. 

Due to its advantages, MRI can contribute to early and accurate diagnosis of deeply infiltrating endometriosis and ovarian endometriosis cysts, without the requirement for an invasive procedure or radiation.⁶

However, clinical history, pelvic examinations and imaging are unable to exclude small and superficial lesions associated with endometriosis.⁵ 

Laparoscopy 

A laparoscopy is a surgical procedure that is the most common and definitive method of diagnosis. It is carried out under general anaesthetic and involves inserting a laparoscope (small telescope) into the abdomen, where the surgeon can observe the pelvic organs for any signs of endometriosis. It also provides information on the size, location, and extent of endometriosis growth.⁷ 

If endometriosis is diagnosed during the laparoscopy, the surgeon may destroy or remove the endometriosis and cysts, and release adhesions (scar tissue). However, it is common for the removal of endometriosis to take place at a later date.

Endometriosis treatment 

Endometriosis treatment depends on the severity of symptoms, age, and if you hope to become pregnant. Treatment includes medicines, and if unsuccessful, surgical intervention may be necessary.

Pain medication

First-line treatment may include non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, to relieve painful menstrual cramps.  

However, long-term use of NSAIDs is not recommended due to side effects, including:⁸

• Stomach ulcers
• Cardiovascular disease
• Acute kidney failure

Hormone therapy 

Hormone treatments suppress the production of oestrogen, a hormone, in the body. Oestrogen encourages endometrial tissue to grow and shed, so limiting oestrogen shrinks endometriosis tissue in the body and reduces pain. Common hormone therapies include:

Combined oral contraceptives (COC)

COC contains oestrogen and progestogen hormones and acts by inhibiting ovulation, causing the lining of the uterus to thin, decreasing menstrual flow and pain.⁸ They can be used long-term but the side effects may require you to try different brands to find the one that suits you.

Gonadotropin-releasing hormone (GnRH) analogues

GnRH analogues are synthetic hormones that cause temporary menopause as they reduce oestrogen production and cause endometriosis tissue to shrink.⁹ GnRH analogues are associated with adverse effects such as bone loss. Therefore, long-term use is not recommended.⁸

Progestins

Progestin is a synthetic form of progesterone, a reproductive hormone. Progestin therapies involve placing a levonorgestrel-releasing intrauterine device (IUD) into the uterus, which thins the lining of the uterus and stops menstrual flow and growth of endometriosis to relieve symptoms.¹⁰ A common example of an IUD includes the Mirena coil.

Aromatase inhibitors

Aromatase inhibitors are a new class of drugs which inhibit the aromatase enzyme, thereby reducing oestrogen production in the ovaries. They significantly decrease the size of lesions and pelvic pain. Long-term effects include bone loss, vaginal dryness, headache, and in premenopausal women, these drugs must be combined with COC, GnRH analogues or progestins.^8,9

Fertility treatment

Endometriosis can negatively impact fertility, and your healthcare team may suggest treatments to improve fertility, such as:¹¹

Laparoscopy

Surgery to remove endometriosis lesions, restoring pelvic anatomy, and ovarian function. Surgery may be used alone or alongside in vitro fertilisation (IVF).

In vitro fertilisation (IVF)

IVF is a procedure where an egg is removed from the ovaries and fertilised with sperm in a laboratory to form an embryo. The embryo is then returned to the uterus to develop. IVF may offer a direct route to pregnancy as it is not dependent on fallopian tube function, which can be compromised with endometriosis, or affected by pelvic adhesions.

The choice of treatment will depend on your age and severity of endometriosis.

Surgery

Surgery may be an option if previous treatments remain unsuccessful.

A laparoscopy may be performed to destroy or remove endometriosis tissue to help improve symptoms. As previously mentioned, this procedure can also be performed at the time of diagnosis, and sometimes before starting other treatments, depending on the severity of your case. 

Hysterectomy 

In severe cases where other less-invasive treatments have not worked and you do not wish to get pregnant, a hysterectomy may be the last resort.⁹

A hysterectomy is the non-reversible removal of the uterus. It may remove endometrial tissue causing pain and treat symptoms such as heavy menstrual bleeding. Following a hysterectomy you can no longer become pregnant or menstruate. 

A hysterectomy is not a guaranteed cure as endometrial tissue can develop outside of the uterus, so it may not alleviate all symptoms. The likelihood of endometriosis returning also depends on whether your ovaries are removed as they produce oestrogen, causing endometriosis to grow. Hysterectomy with removal of ovaries is an oophorectomy which causes early menopause and often requires hormone replacement therapy (HRT).⁹

On one hand, the lack of oestrogen produced by the ovaries may improve endometriosis pain. However, if any endometrial tissue remains after surgery, it can continue to cause symptoms.

It is important that you discuss the advantages and disadvantages of undergoing a hysterectomy with your healthcare provider. Getting a second opinion is recommended to ensure it is the right choice for you.  

Summary 

Endometriosis is a chronic condition characterised by the growth of endometrial tissue outside of the uterus. Diagnosing endometriosis can be complex as the symptoms can indicate a range of other conditions. Diagnosis includes a combination of clinical history, pelvic examination, imaging tests, and laparoscopy. Treatment pathways are chosen in collaboration with your healthcare team, typically starting with medications. Medications can include NSAIDs to manage pain, and hormone therapies to suppress oestrogen production which facilitates endometriosis. Surgical interventions involve a laparoscopy to remove endometrial tissue in those who face fertility difficulties, or a hysterectomy in severe cases in those who do not wish to become pregnant.