Endometriosis

Endometriosis is a chronic, estrogen-dependent, inflammatory condition characterized by the presence of tissue similar to the endometrium outside the uterus. These ectopically located tissues bleed in response to the menstrual cycle but cannot be expelled from the body, leading to inflammation, fibrosis, and adhesions in surrounding tissues. It most commonly affects pelvic organs but can also occur in extrapelvic locations.

Epidemiology

Endometriosis affects approximately 6% to 10% of women of reproductive age. Among women presenting with infertility, the prevalence ranges from 30% to 50%. Although the disease is widespread globally, prevalence rates may vary by ethnic and geographic factors. For example, lower prevalence has been reported in women of Asian descent, while higher rates are observed in populations of European origin. Diagnosis is typically made between the ages of 25 and 35, although symptoms may begin during adolescence. Symptoms generally improve after menopause.

Etiopathogenesis

Several mechanisms have been proposed for the development of endometriosis. The most widely accepted theory is the retrograde menstruation hypothesis. According to this theory, endometrial cells shed during menstruation flow backward through the fallopian tubes into the pelvic cavity where they implant. However, this theory fails to explain why endometriosis develops only in certain individuals despite the presence of retrograde flow in most women.

Alternative theories include:

• Stem Cell Theory: Suggests that stem cells originating from the bone marrow or endometrium can differentiate and form ectopic endometrial tissue.
• Immunological Dysfunction Theory: Proposes that the body lacks the ability to clear ectopic cells or that there is an alteration in the immune response.
• Coeleomic Metaplasia Theory: States that peritoneal cells can transform into endometrial-like cells under hormonal or inflammatory stimuli.

It is also possible that multiple mechanisms interact. Additionally, genetic predisposition, hormonal factors, and environmental influences play roles in the development of endometriosis.

Clinical Manifestations

Symptoms of endometriosis vary among individuals. The most common symptoms include:

• Dysmenorrhea: Painful menstrual periods.
• Chronic Pelvic Pain: Persistent lower abdominal pain unrelated to the menstrual cycle.
• Dyspareunia: Pain during sexual intercourse.
• Infertility: Infertility rates among women with endometriosis vary by stage. In minimal to mild stages, rates are around 20% to 30%, rising to 40% to 50% in advanced stages.
• Dysuria and Dyschezia: Pain during urination and defecation.

These symptoms can significantly reduce quality of life. Additional findings such as fatigue, nausea, and gastrointestinal disturbances during menstruation may also occur.

Diagnostic Methods

Diagnosis is typically based on clinical history and physical examination, but definitive diagnosis requires laparoscopy with biopsy. Auxiliary diagnostic tools include:

• Ultrasound (US): Effective in detecting endometriomas.
• Magnetic Resonance Imaging (MRI): Used for diagnosing deep infiltrative endometriosis.
• Serological Markers: CA-125 levels may be elevated in some patients. However, its use in diagnosis is limited due to low specificity and sensitivity. Reported sensitivity for CA-125 ranges from 24% to 94%, and specificity from 60% to 90%.
• New Biomarkers: In recent years, alternative biomarkers such as microRNAs, cytokines, and neural growth factors have been investigated but have not yet entered clinical practice.

Types of Endometriosis

• Superficial Peritoneal Endometriosis: The most common and earliest form.
• Endometrioma: Ovarian cysts, also known as chocolate cysts.
• Deep Infiltrative Endometriosis (DIE): Invades deeply into structures such as the vagina, rectum, and bladder.
• Scar Endometriosis: May develop following surgical incisions such as cesarean section. Diagnosis of abdominal wall endometriosis can be challenging; differential diagnosis must consider the possibility of misidentifying benign or malignant masses.

Treatment Approaches

Endometriosis treatment must be individualized. The goals are to reduce pain, preserve fertility, and improve quality of life.

1. Medical Treatment

• Pain Management: Nonsteroidal anti-inflammatory drugs (NSAIDs) are used.
• Hormonal Therapy: Combined oral contraceptives, GnRH agonists, progestins, and aromatase inhibitors may be preferred.

2. Surgical Treatment

• Laparoscopic excision or ablation is preferred.
• Surgical techniques can influence recurrence rates. Excision surgery provides lower recurrence rates (20%–30%) compared to ablation.
• After removal of endometriomas, pregnancy rates have been reported to increase by 20% to 30%.

3. Supportive Approaches

• Complementary methods such as physical therapy, psychological counseling, nutritional support (e.g., gluten-free diet recommendations), yoga, and acupuncture may help manage symptoms in some patients.

Endometriosis and Psychosocial Effects

Endometriosis is not limited to physical symptoms; it can severely impact psychological and social well-being. Chronic pain may lead to reduced quality of life, sexual dysfunction, loss of work productivity, depression, and anxiety. Therefore, within a multidisciplinary framework, nursing care, psychological counseling, and social support are increasingly emphasized.

Endometriosis and Pregnancy

Endometriosis can directly cause infertility. Reduced pregnancy rates in women with endometriosis are explained by several mechanisms, including distortion of pelvic anatomy, diminished ovarian reserve, negative effects of endometriomas on ovarian function, obstruction of tubal function, and increased uterine contractility. Endometriosis may also impair embryo implantation by causing abnormalities in the immune system and peritoneal fluid composition.

In these women, achieving spontaneous pregnancy may take longer, and assisted reproductive technologies (ART) may be necessary. In particular, women with endometriomas more frequently undergo procedures such as in vitro fertilization (IVF). However, some forms of endometriosis, especially superficial peritoneal endometriosis, may have a lesser impact on fertility.

Surgical treatment, particularly in younger patients, can improve pregnancy rates by removing lesions. However, careful planning is required due to the risk of recurrence and the potential damage surgery may cause to ovarian reserve.

Endometriosis Models and Experimental Studies

Animal models are used to better understand endometriosis pathophysiology and to develop new therapeutic approaches. One such model is the intraocular endometriosis model in rats. In this model, endometrial tissue is implanted into the ocular cavity of rats to observe inflammatory responses and tissue changes. Such experimental models play a crucial role in understanding the cellular and molecular mechanisms of endometriosis.

Animal models are also used to evaluate drug efficacy, test novel molecules, and observe the effects of hormonal or immune system interventions. However, limitations of animal studies must be considered, and findings should be interpreted in light of human research.

Abdominal Wall Endometriosis

Although rare, endometriosis can occur outside the classic pelvic locations, including the abdominal wall. This typically develops in scar tissue following previous surgeries, especially cesarean section or hysterotomy. Abdominal wall endometriosis usually presents as a palpable mass at the surgical scar site with increased pain during menstruation. Physical examination, ultrasound, and rarely computed tomography (CT) aid in diagnosis. Treatment is generally surgical, and complete excision of the lesion can eliminate symptoms.

Such extrapelvic endometriosis cases can pose diagnostic challenges and are often misdiagnosed as tumor masses. Therefore, careful differential diagnosis is essential when clinical suspicion arises.

Case Reports

Many case reports on endometriosis appear in the literature. These cases are typically characterized by atypical lesion locations, diagnostic delays, or rare clinical symptoms. For example, isolated endometriosis within the rectus abdominis muscle, endometriosis nodules in the abdominal wall, and endometriosis in unusual locations such as the eye or lung have been documented.

These cases demonstrate that endometriosis is not confined to the pelvis and can have systemic effects. They also emphasize that diagnosis requires not only clinical observation but also multidisciplinary evaluation and histopathological confirmation.

Prognosis and Risk of Recurrence

Endometriosis is a chronic disease with a tendency to recur. Even after surgical treatment, recurrence rates remain high, with some studies reporting rates of up to 40% to 50% within five years. Recurrence risk depends on disease extent, type of treatment, duration of hormonal suppression, and individual variations. In particular, recurrent lesions are often observed after conservative surgery in patients desiring fertility.

Disease suppressed by medical therapy frequently reactivates after discontinuation of medication. Therefore, long-term follow-up and, if necessary, reconfiguration of treatment regimens may be required.

Public Health Significance

Endometriosis is not merely an individual health issue but also has significant societal and economic impacts. It leads to multifaceted consequences such as loss of workforce productivity, frequent healthcare visits, high treatment costs, and reduced social quality of life. Additionally, due to diagnostic delays, women may undergo unnecessary treatments and receive incorrect diagnoses for years.

In this context, increasing awareness at both individual and societal levels, educating healthcare professionals, and developing comprehensive health policies are essential. Active involvement of nurses, women’s health specialists, and psychosocial support teams plays a critical role in improving patients’ quality of life.