Endometriosis overview

# Overview
Endometriosis is a disease characterized by the presence of functional endometrial tissue outside the uterine cavity. The most commonly affected sites are the ovaries, broad ligaments, and the surrounding pelvic structures. Endometriosis can also affect distant sites such as the lungs, ureters, and CNS. The exact pathogenesis of endometriosis has not been established, although several theories have been put forth. The Sampson theory of retrograde menstruation, the coelomic metaplasia theory, and the lymphatic and vascular dissemination theory offer possible explanations for the mechanisms of implantation and invasion of endometrial tissue outside the uterine cavity. Endometriosis is a cause of dysmenorrhea and dyspareunia; accordingly, it must be differentiated from other conditions presenting with similar symptoms such as adenomyosis, pelvic inflammatory disease, pelvic congestion syndrome, and submucosal uterine fibroids. The goal of medical therapy is pain management and the reduction of the endometrial implant size. Therapeutic options include GnRH agonists and danazol. Surgical therapy is reserved for patients with severe forms of the disease or who fail to improve with standard medical therapy.

# Historical Perspective
In the early 19th century, endometriosis was described as adenomyomas. In the 1920s, endometriosis was differentiated from adenomyosis and a detailed description of the disease was given by Cullen and Sampson. Sampson proposed the theory of retrograde menstruation as the pathogenesis of the disease.

# Classification
Endometriosis is classified into four stages of severity based on the revised American Society for Reproductive Medicine scoring system. The staging is based on the distribution of the lesions and the presence of adhesions.

# Pathophysiology
The exact pathogenesis of endometriosis is not clear and several theories have made an attempt to describe its pathogenesis. The Sampson theory of retrograde menstruation, the coelomic metaplasia theory, and the lymphatic and vascular dissemination theory explain the implantation and invasion of endometrial tissue outside the uterine cavity. Immunologic factors and genetic factors are also thought to play a role in the pathogenesis of endometriosis.

# Causes
The exact cause of endometriosis is unknown; the disease is thought to be multifactorial in origin.

# Differential Diagnosis
Endometriosis is a cause of dysmenorrhea and dyspareunia. Endometriosis must be differentiated from other conditions presenting with similar symptoms such as adenomyosis, pelvic inflammatory disease, pelvic congestion syndrome, and submucosal uterine fibroids.

# Epidemiology and Demographics
Endometriosis affects approximately around 11% of the female population in the reproductive age group. Endometriosis is more common among Caucasians than among African Americans. The disease accounts for the majority of patients with chronic pelvic pain and infertility.

# Risk Factors
The risk factors predisposing women to the development of endometriosis include early age at menarche, nulliparity, positive family history, and the presence of congenital cervical stenosis or obstructive lesions in the uterovaginal tract.

# Screening
Standard screening for endometriosis is not recommended.

# Natural History, Complications and Prognosis
Endometriosis is a condition affecting females in the reproductive age group. It has a wide spectrum of presentations. It can be asymptomatic, present with premenstrual spotting and cyclic abdominal pain, present with infertility or chronic pelvic pain, or present as deep endometriosis with dyspareunia, dyschezia, and cyclic rectal bleeding. Complications of endometriosis include infertility, fibrosis, chocolate cyst, and, rarely, effects on other organs such as the lungs.

# Diagnosis

## History and Symptoms
Endometriosis is a condition affecting women in the reproductive age group. The patients with endometriosis may have positive family history, presence of congenital cervical stenosis or obstructive lesions in the uterovaginal tract The presenting features include cyclical abdominal pain, dysmenorrhea, pain with passing stools, and pain with intercourse.

## Physical Examination
Examination findings on digital vaginal examination and speculum examination include a fixed retroverted uterus, palpable nodularity of the uterosacral ligaments, and cul-de-sac with narrowing of the posterior fornix.

## Laboratory Findings
Laboratory findings associated with endometriosis include features of iron deficiency anemia and increased levels of cancer antigen-125 and interleukin 1.

## EKG
There are no specific EKG findings associated with endometriosis.

## Chest X-Ray
On chest X-ray, chest endometriosis is characterized by small bubbles at the level of the right diaphragm associated with pneumothorax.

## CT
CT of endometriosis is not the most sensitive noninvasive method for the diagnosis; MRI is more useful. On CT scans, endometriosis shows catamenial pneumothorax, hemothorax, and lung nodules.

## MRI
MRI is useful for the assessment of the anatomical locations and severity of the disease. The typical appearance of endometriosis includes a characteristic hyperintensity on T1-weighted images and a hypointensity on T2-weighted images.

## Ultrasound
Abdominal ultrasound is useful to differentiate endometriosis from other cystic lesions of female reproductive system. The endometrial lesions have increased vascularity and will demonstrate increased Doppler flow. Transvaginal ultrasound is more sensitive than abdominal ultrasound.

## Other Imaging Findings
There are no associated other imaging findings with endometriosis.

## Other Diagnostic Studies
Diagnostic laparoscopy is the gold standard to assess the severity and extent of the disease.

# Treatment

## Medical Therapy
The primary goal of medical therapy is pain management and regression of the endometrial lesions. NSAIDS are useful for pain management. There are many therapeutic options available to reduce the size of endometrial lesions. Gonadotrophin releasing hormone agonists and danazol are widely used. Continuous oral contraceptive pill (OCP) use is also helpful in patients with mild to moderate endometriosis.

## Surgical Therapy
Patients with failed medical therapy and patients with stage 3 or stage 4 disease are candidates for surgical therapy. Laser and excision are done for isolated lesions, while total hysterectomy is reserved for patients with extensive disease.

## Primary Prevention
There are no primary preventive measures for endometriosis.

## Secondary Prevention
There are no secondary preventive measures for endometriosis.