What is endometriosis?

What is Endometriosis?

Endometriosis is an inflammatory disease characterized by endometrial-like tissue growing outside the uterus, affecting approximately 10% of individuals assigned female at birth during their reproductive years, causing chronic pelvic pain, infertility, and systemic effects that significantly impact quality of life. 1

Definition and Prevalence

• Endometriosis affects approximately 176-190 million women worldwide 1, 2
• The condition is defined by the presence of endometrial-like tissue (lesions) outside the uterine cavity, typically in the pelvis 1
• It is now recognized as a chronic systemic disease rather than just a gynecological condition 3

Classification and Types

Endometriosis is classified based on location and depth into three main types 1:

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

Clinical Presentation

Common Symptoms

• Pain manifestations (90% of patients) 4:
  • Dysmenorrhea (painful periods)
  • Chronic pelvic pain (non-menstrual)
  • Dyspareunia (painful intercourse)
• Fertility issues (26-50% report infertility) 4, 2
• Systemic symptoms 1, 2:
  • Fatigue
  • Gastrointestinal symptoms
  • Urinary symptoms
  • Mood disorders

Risk Factors

• Younger age at menarche
• Shorter menstrual cycle length
• Lower body mass index
• Nulliparity
• Congenital obstructive müllerian anomalies 4

Pathophysiology

While the exact cause remains uncertain, several mechanisms contribute to endometriosis 5, 3:

• Retrograde menstruation (most widely accepted theory)
• Hormonal factors (estrogen-dependent condition)
• Neurological factors (pain sensitization)
• Immunological factors (altered immunity and inflammatory responses)
• Genetic predisposition
• Metabolic alterations in liver and adipose tissue 3

Diagnosis

Diagnosis of endometriosis is challenging and often delayed:

• Diagnostic delay: Average of 5-12 years after symptom onset 1, 4
• Multiple consultations: Most women consult 3 or more clinicians prior to diagnosis 4
• Definitive diagnosis: Requires surgical visualization with histological verification 6
• Non-invasive approaches:
  • Clinical diagnosis based on symptoms
  • Transvaginal ultrasound (TVUS)
  • Pelvic MRI (particularly useful for ovarian endometriomas and deep endometriosis) 1, 4

Impact on Quality of Life

Endometriosis substantially affects quality of life 1:

• Interferes with daily activities, work, and relationships
• Economic burden estimated at $69.4 billion annually
• Comparable societal costs to other chronic conditions like type 2 diabetes, Crohn's disease, and rheumatoid arthritis 6

Treatment Approaches

Treatment depends on the patient's symptoms, goals, and desire for pregnancy 4:

1. First-line treatments:

   • Hormonal medications (combined oral contraceptives and progestin-only options)
   • These lead to clinically significant pain reduction in most patients

2. Surgical options:

   • Laparoscopic removal of lesions when hormonal therapies are ineffective or contraindicated
   • Hysterectomy with removal of lesions for severe cases unresponsive to other treatments

3. Second and third-line treatments:

   • GnRH agonists and antagonists
   • Aromatase inhibitors

Treatment Limitations

• 11-19% of patients have no pain reduction with hormonal medications
• 25-34% experience recurrent pain within 12 months of stopping hormonal treatment
• 25% of patients who undergo hysterectomy experience recurrent pelvic pain 4

Emerging Research

Recent research is focusing on 2:

• Understanding pathogenesis
• Identifying disease subtypes
• Developing non-invasive diagnostic methods
• Targeting non-hormonal treatments acceptable to women who wish to conceive
• Self-management strategies including nutrition