Patients present with one, or usually more of the following signs and symptoms: pelvic pain, lower abdominal and/or back pain [8], dysmenorrhea, dyspareunia, dyschezia, heavy bleeding during and between periods, irregular menstruation and urinary frequency. They may also complain of nausea, bloating and pain during or after exercise. Sometimes the presentation may appear similar to be that of a genito-reproductive tract tumor, in which case a detailed work up can help differentiate the disease from cancer.

Work up includes a detailed history, physical examination and tests.

Laboratory tests

• Complete blood count
• Urinalysis
• Blood cultures (to rule out STDs)
• Serum cancer antigen test (Ca-125)
• Antibody testing against Thomsen-Friedenreich (T) antigen (Gal beta1-3GalNAc) bearing proteins

Imaging 

The following imaging studies may be performed:

• Transvaginal ultrasound
• Endorectal ultrasound
• CT scan and MRI

Other tests

• Biopsy
• Pelvic laparoscopy (It is the primary modality for assessing and diagnosing endometriosis).

Test results

Diagnosis is based on physical findings and test results. Imaging studies in particular play an important role in disease identification.

Conservative management

It includes the use of analgesics to relieve pelvic and abdominal pain and the use of hormone therapy like the use of Danazol or progesterone. Oral contraceptives have proved to be effective in slowing disease progression. In many women, menopause (natural or surgical) will abate the process [9].

Surgical intervention

If the disease cannot be satisfactorily managed conservatively, it may be treated surgically. Surgical intervention is of two types. The first is called conservative or semi conservative surgical intervention in which reproductive organs are spared. The second type, called radical surgery, involves a total hysterectomy and bilateral oophorectomy as well as adhesiolysis. This type is usually only performed in women past the child bearing age or in women with very serious, grade IV endometriosis.

It is a progressive disease with a high rate of recurrence even after treatment. However, endometriosis has been found to resolve spontaneously in one third of women who are not actively treated [7]. Prognosis depends upon the stage of the disease. It has 4 stages.

• Stage I: Only superficial lesions and adhesions are present.
• Stage II: Some superficial as well as deep lesions are present
• Stage III: Presence of superficial and deep lesions as well as presence of endometriomas in the ovaries
• Stage IV: All the above findings plus large endometriomas and extensive adhesions.

The exact cause of endometriosis is unknown. Several factors have been implicated in its development. The two main theories; metastatic and metaplastic theories have been explained in a later section. Humoral antibodies to endometrial tissue have also been found in sera of women with endometriosis [2]. Some women may also be genetically predisposed to this condition. Overall it is thought to be a collection of several factors, not just one, that ultimately cause this disease. As for why some women may be prone to this disease as opposed to those who are not, studies reveal that it varies on individual-based responses.

Incidence

Endometriosis is not a common occurrence. Approximately, endometriosis occurs in roughly 4–10% of women [3]. It has a prevalence of 7-10% in the United States.

Age

It is principally a disease of women in their active reproductive life. So it is common in women aged between mid-twenties and early-forties.

Race

There does not appear to be any predilection to a particular race or ethnicity.

The most common site of ectopic endometrial tissue is the ovary. The next most common sites, in decreasing order of frequency are: Uterine ligaments, rectovaginal septum, cul de sac, pelvic peritoneum, large and small bowel, appendix, cervical mucosa, vagina, fallopian tubes and laparotomy scars. Two major theories for the development of endometriosis have been proposed [4], they are:

• Metastatic theory

According to this theory, there is lymphatic or hematogenous ‘metastasis’ of endometrial tissue to abnormal locations. Retrograde menstruation may be the cause of peritoneal endometriosis, for example.

• Metaplastic theory

According to this theory, endometrial tissue may itself arise directly from coelomic epithelium at extrauterine sites. This coelomic epithelium is from which the mullerian ducts and ultimately the endometrium itself originates during embryonic development. Under the influence of factors that are still unclear, there may be abnormal production of endometrial gland and stromal cells in sites other than the uterus.

Specific abnormalities that distinguish normal endometrium from endometriotic tissue are highlighted below [5].

1. Profound activation of inflammatory cascade, characterized by high levels of prostaglandin E2, IL-1B, IL-6 and TNF. 
2. Marked upregulation of estrogen production mainly due to high levels of the key steroidogenic enzyme aromatase [6].

Endometriosis may be prevented or at least slowed by use of birth control pills [10]. Birth control pills act to decrease the production of hormones by the body which are necessary to support the endometrial tissue’s growth and division.

Endometriosis is defined as ectopic production or occurrence of endometrial tissue in extrauterine sites [1]. Endometrium is the innermost layer lining the uterus. Due to some reasons, as discussed in detail in later sections, this tissue may occur abnormally in extrauterine sites. Commonly, the ectopic tissue consists of both the endometrial glands and the stroma. It may occur anywhere in the body but typically remains within the abdominal and pelvic cavities. It may be confused with cancer so a thorough knowledge of the disease and its manifestation is imperative for proper diagnosis and treatment.

Definition

Endometriosis can be defined as abnormal presence of endometrial tissue (cells of the inner lining of the uterus), outside of the uterus. For example, endometrial tissue may abnormally occur in the ovaries, uterine ligaments, fallopian tubes, peritoneum, as well as other sites.

Cause

There is no known specific cause of endometriosis. It may be genetic or due to some immune dysfunction or it may simply be due to displacement and/or abnormal growth of uterine tissue in sites other than the uterus.

Symptoms

It may be asymptomatic but in symptomatic patients, it presents with painful menstruation, pelvic pain and in severe cases, infertility. Other symptoms include pain during urination or defecation, heavy menstrual bleeding, mid-cycle bleeding, nausea and vomiting and lower back pain.

Treatment

Treatment involves the use of contraceptive pills and painkillers. Surgical intervention may be needed in severe cases.

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