What is Endometriosis
Endometriosis is a chronic inflammatory disease characterized by endometrial-like tissue located outside the uterine cavity, associated with inflammation and fibrosis, affecting approximately 10% of women during their reproductive years. 1, 2
Core Definition and Pathophysiology
Endometriosis occurs when tissue resembling the endometrial lining grows on or extends below the peritoneal surface outside the uterus. 1, 2 The condition is:
- Estrogen-dependent and progesterone-resistant, making it hormone-responsive 2
- Inflammatory in nature, with chronic inflammation affecting an estimated 176 million women worldwide 2
- Proliferative, with lesions that can grow and spread over time 2
Deep endometriosis (DE) specifically refers to lesions extending deeper than 5 mm under the peritoneal surface or those involving/distorting the bowel, bladder, ureter, or vagina. 2
Clinical Presentation
The disease manifests with highly variable symptoms ranging from asymptomatic to debilitating: 1, 2
Pelvic pain is the most common symptom, presenting as:
Infertility affects approximately 50% of patients with endometriosis 1, 2
Additional symptoms include fatigue, gastrointestinal symptoms, urinary symptoms, and mood disorders 3
Systemic Nature of the Disease
Endometriosis should be understood as a systemic disease rather than just a pelvic condition. 2, 4 The disease extends beyond the pelvis by:
- Affecting metabolism in liver and adipose tissue 4
- Causing systemic inflammation throughout the body 4
- Altering gene expression in the brain, leading to pain sensitization and mood disorders 4
- Increasing cardiovascular disease risk, including stroke (HR 1.34,95% CI 1.10-1.62) 5
Etiology and Risk Factors
The disease has a multifactorial origin: 2
- Genetic factors with possible epigenetic influences 2
- Environmental exposures contributing to development 2
- Shared risk factors with inflammatory and chronic pain conditions 3
Economic and Quality of Life Impact
The annual economic burden is estimated at $69.4 billion, comparable to type 2 diabetes, Crohn's disease, and rheumatoid arthritis. 1, 2 The disease significantly impacts:
- Physical health and daily activities 1, 6
- Emotional well-being and mental health 6
- Social interactions and relationships 6
- Professional performance and work productivity 6
Diagnostic Challenges
Diagnosis is typically delayed by 5-12 years after symptom onset, with most women consulting 3 or more clinicians before diagnosis. 7 Key challenges include:
- Variable presenting symptoms that overlap with other conditions 1
- Nonspecific physical examination findings 1
- Historical requirement for surgical confirmation, though clinical diagnosis is now acceptable and does not require surgery before initiating empiric treatment 5
Important Clinical Pitfalls
- Negative imaging does not exclude endometriosis—superficial peritoneal disease is poorly detected by all imaging modalities 5
- Current classification systems (r-ASRM, Enzian, EFI) have significant limitations in correlating with symptom severity and predicting treatment outcomes 2
- Up to 44% of women experience symptom recurrence within one year after treatment, requiring ongoing management 5