What is endometriosis?

What is Endometriosis?

Endometriosis is an inflammatory disease process characterized by lesions of endometrial-like tissue outside the uterus that is associated with pelvic pain and/or infertility. 1

Definition and Prevalence

Endometriosis affects approximately 10% of individuals assigned female at birth during their reproductive years 1, 2, with an estimated 176 million women affected worldwide 1, 3. The condition is defined by the presence of endometrial-like tissue growing outside the uterine cavity, typically in the pelvis, causing inflammation and fibrosis 1.

Pathophysiology

Endometriosis is characterized by:

• Inflammatory processes where endometrial-like tissue grows outside the uterus
• Estrogen-dependent growth patterns
• Progesterone resistance in many cases
• Multifactorial etiology including:
  • Genetic factors with possible epigenetic influences
  • Possible environmental exposures
  • Retrograde menstruation (a leading theory for origin)
  • Altered immunity and inflammatory responses 1, 4

Clinical Presentation

Endometriosis presents with varying symptoms:

• Pain manifestations (affecting 90% of patients 2):

  • Dysmenorrhea (painful periods)
  • Chronic pelvic pain (non-menstrual)
  • Dyspareunia (painful intercourse)
  • Dyschezia (painful bowel movements)
  • Dysuria (painful urination)

• Fertility issues:

  • Approximately 26-50% of patients experience infertility 2, 5

• Other symptoms:

  • Fatigue
  • Gastrointestinal and urinary symptoms
  • Mood disorders 5

Types and Classification

Endometriosis is classified based on location and depth:

• Peritoneal (superficial): Lesions on the peritoneal surface
• Ovarian endometriomas: Cystic lesions in the ovaries
• Deep endometriosis (DE): Lesions extending deeper than 5mm under the peritoneal surface or involving/distorting bowel, bladder, ureter, or vagina 1, 5

Diagnostic Challenges

Diagnosis of endometriosis is often delayed:

• Average delay of 5-12 years after symptom onset 2
• Most women consult 3 or more clinicians prior to diagnosis 2
• Historically required surgical visualization with histologic confirmation
• Modern approach includes clinical diagnosis supported by imaging:
  • Transvaginal ultrasound (TVUS)
  • Pelvic MRI 1, 2

Systemic Disease Perspective

Recent evidence indicates endometriosis should be considered a systemic disease rather than just a pelvic condition 4:

• Affects metabolism in liver and adipose tissue
• Leads to systemic inflammation
• Alters gene expression in the brain causing pain sensitization and mood disorders
• Shares genetic risk factors with other inflammatory and chronic pain conditions 4, 5

Treatment Approaches

Treatment depends on the patient's goals and symptom severity:

• First-line hormonal treatments:

  • Combined oral contraceptives
  • Progestin-only options
  • Effective for pain reduction in many patients, though 11-19% have no pain reduction 2

• Surgical options:

  • Laparoscopic removal of lesions when hormonal therapies are ineffective
  • Definitive treatment in many cases, but recurrence is possible

• Second and third-line treatments:

  • GnRH agonists and antagonists
  • Aromatase inhibitors 2

Impact on Quality of Life

Endometriosis substantially affects quality of life:

• Can interfere with daily activities, work, and relationships 6
• Economic burden estimated at $69.4 billion annually, similar to other chronic diseases like type 2 diabetes, Crohn's disease, and rheumatoid arthritis 1, 3

Understanding endometriosis as a complex, systemic inflammatory condition rather than simply a gynecological disorder is crucial for proper diagnosis and management of this challenging disease.