What is endometriosis?

Endometriosis: Definition and Clinical Implications

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, affecting approximately 10% of women during their reproductive years. 1

Definition and Pathophysiology

• Endometriosis is defined as endometrial-like tissue located outside of the endometrial cavity, associated with inflammation and fibrosis, on or extending below the peritoneal surface 1
• The condition is characterized by chronic inflammation and affects an estimated 176 million women worldwide 1, 2
• Deep endometriosis (DE) is defined as lesions extending deeper than 5 mm under the peritoneal surface or those involving or distorting bowel, bladder, ureter or vagina 1

Clinical Presentation

• The clinical presentation is highly variable, ranging from asymptomatic to severe symptoms that significantly impact daily activities 1
• Pelvic pain is the most common symptom (90% of cases), manifesting as: 1, 2
  • Dysmenorrhea (painful menstruation)
  • Dyspareunia (painful intercourse)
  • Dyschezia (painful bowel movements)
  • Dysuria (painful urination)
  • Nonmenstrual pelvic pain
• Approximately 50% of patients with endometriosis experience infertility 1, 2
• Diagnosis is often delayed by 5-12 years after symptom onset, with most women consulting 3 or more clinicians prior to diagnosis 2

Comprehensive Characterization

Endometriosis should be understood as a systemic disease rather than just a pelvic condition, with the following key characteristics: 1, 3

• Multifactorial etiology including genetic factors with possible epigenetic influences 1
• Environmental exposure effects 1
• Pain syndrome elements beyond localized pelvic pain 1
• Proliferative nature of the lesions 1
• Hormone responsiveness (estrogen-dependence and progesterone resistance) 1, 3
• Systemic effects including altered metabolism in liver and adipose tissue 3
• Systemic inflammation 3
• Altered gene expression in the brain causing pain sensitization and mood disorders 3

Diagnostic Approaches

• Definitive diagnosis traditionally requires surgical visualization of lesions with histological verification 2, 4
• However, a suspected clinical diagnosis can be made based on symptoms, physical examination findings, and imaging 2
• Imaging modalities include: 1, 2
  • Transvaginal ultrasound (TVUS) - first-line imaging modality
  • Expanded protocol TVUS studies for identifying and mapping deep endometriosis
  • Magnetic resonance imaging (MRI) - particularly useful for deep endometriosis
• Normal physical examination and imaging do not exclude the diagnosis 2

Treatment Options

• First-line treatments for symptomatic premenopausal women not desiring immediate pregnancy include: 2, 5
  • Combined oral contraceptives
  • Progestin-only options
• Surgical removal of lesions (usually laparoscopic) should be considered when: 2
  • First-line hormonal therapies are ineffective
  • Hormonal treatments are contraindicated
• Second-line hormone therapies include GnRH agonists and antagonists 2
• Third-line treatments include aromatase inhibitors 2
• Hysterectomy with surgical removal of lesions may be considered when initial treatments are ineffective, though approximately 25% of patients still experience recurrent pain 2

Challenges and Pitfalls

• Diagnosis is often delayed due to variable symptoms and nonspecific physical examination findings 1, 2
• Approximately 11-19% of individuals have no pain reduction with hormonal medications 2
• 25-34% experience recurrent pelvic pain within 12 months of discontinuing hormonal treatment 2
• Current classification systems (r-ASRM, Enzian, EFI) have limitations in correlating with symptom severity and predicting treatment outcomes 1
• Even after hysterectomy, approximately 25% of patients experience recurrent pelvic pain and 10% require additional surgery 2

Economic and Quality of Life Impact

• Endometriosis substantially affects quality of life for women and their families 4
• The economic burden is estimated at $69.4 billion annually, similar to other chronic diseases like type 2 diabetes, Crohn's disease, and rheumatoid arthritis 1, 4

Understanding endometriosis as a systemic inflammatory disease with manifestations beyond the pelvis is crucial for proper diagnosis and comprehensive treatment approaches that address the full spectrum of symptoms and improve quality of life.