Endometriosis is a condition where tissue similar to the lining inside the uterus, known as the endometrium, grows outside of it. This misplaced tissue most commonly affects the peritoneum, making peritoneal endometriosis the most frequently occurring form of the condition. It can lead to pain and other symptoms that impact daily life.
What is Peritoneal Endometriosis?
The peritoneum is a thin, two-layered membrane lining the abdominal cavity and covering most organs within it, including the uterus, ovaries, and intestines. Peritoneal endometriosis occurs when endometrial-like tissue implants and grows on this lining.
These lesions can be found on pelvic organs, the abdominal wall, and the diaphragm. The misplaced tissue behaves similarly to the uterine lining, thickening, breaking down, and bleeding in response to hormonal changes during the menstrual cycle. Unlike menstrual blood from the uterus, this blood has no clear way to exit the body, leading to inflammation, scar tissue, and adhesions. Lesions can vary in size and number, from a few small spots to many across multiple areas of the peritoneum.
Common Symptoms
Individuals with peritoneal endometriosis experience a range of symptoms, with chronic pelvic pain as a primary concern. This pain can manifest as severe menstrual cramps (dysmenorrhea), which may begin before and extend beyond the menstrual period. Pain during or after sexual intercourse (dyspareunia) is also common.
Discomfort extends to bodily functions, with some individuals experiencing painful bowel movements or urination, especially during menstruation. Other symptoms include unusually heavy menstrual bleeding, bleeding between periods, and fatigue.
Causes and Risk Factors
The exact cause of endometriosis remains unclear, but several theories explain its development.
Retrograde Menstruation
One widely accepted theory is retrograde menstruation, where menstrual blood containing endometrial cells flows backward through the fallopian tubes into the pelvic cavity instead of exiting the body. These cells can then implant and grow on the peritoneal surface. While many individuals experience retrograde menstruation, only a subset develop endometriosis, suggesting other factors are involved.
Coelomic Metaplasia
Another theory is coelomic metaplasia, which proposes that cells lining the peritoneal cavity can transform into endometrial-like tissue under certain conditions. This theory helps explain cases of endometriosis found in unusual locations or in individuals without a uterus.
Lymphatic and Vascular Spread
The lymphatic and vascular spread theory suggests that endometrial cells can travel through the lymphatic system or bloodstream to distant sites in the body, leading to lesion formation.
Several factors can increase an individual’s risk of developing endometriosis.
Genetic Predisposition
A genetic predisposition plays a role, with individuals having a first-degree relative (mother, sister, or daughter) with endometriosis facing a 7 to 10 times higher risk.
Menstrual Characteristics
Menstrual characteristics also contribute, including starting menstruation at an early age, having shorter menstrual cycles (less than 27 days), or experiencing heavy periods lasting longer than seven days.
Environmental Factors
Environmental factors, such as exposure to endocrine-disrupting chemicals like dioxins, bisphenol A (BPA), and phthalates, may also increase the risk.
Diagnosis Methods
Diagnosing peritoneal endometriosis involves a combination of approaches. The process begins with a thorough review of the individual’s medical history, focusing on symptoms like chronic pelvic pain and menstrual irregularities. A physical examination, including a pelvic exam, may reveal cysts or scar tissue, though these findings are not definitive for endometriosis.
Imaging techniques such as ultrasound and Magnetic Resonance Imaging (MRI) can help identify some forms of endometriosis, like ovarian cysts (endometriomas) or deep infiltrating lesions. These methods have limitations, as they may not detect superficial peritoneal implants. A definitive diagnosis of peritoneal endometriosis requires laparoscopic surgery.
During a laparoscopy, a surgeon makes small incisions in the abdomen and inserts a thin, lighted viewing tool called a laparoscope. This allows for a direct visual inspection of the pelvic organs and the peritoneum to identify endometrial-like lesions, scar tissue, and adhesions. If suspicious areas are found, tissue samples are taken for a biopsy. A pathologist then examines these samples under a microscope to confirm the presence of endometrial glands and stroma.
Treatment Approaches
Managing peritoneal endometriosis involves an approach tailored to the individual’s symptoms and goals.
Medical Management
Medical management includes pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs), to manage pain. Hormonal therapies reduce estrogen levels or suppress menstrual cycles, inhibiting the growth of endometrial-like tissue.
Hormonal options include:
Combined oral contraceptive pills, which prevent ovulation and thin the uterine lining, making periods lighter and less painful.
Progestins, available as pills, injections, or intrauterine devices, which thin the uterine lining and reduce or stop periods.
Gonadotropin-releasing hormone (GnRH) agonists, which temporarily induce a menopause-like state by suppressing ovarian estrogen production, leading to lesion regression and pain relief. These hormonal treatments are temporary, with effects reversing upon discontinuation.
Surgical Intervention
Surgical intervention is a primary treatment strategy, especially when medical management is insufficient or fertility is a concern. Laparoscopic surgery is the preferred method, allowing for the removal or destruction of endometrial implants and scar tissue. Two main surgical techniques are used:
Excision: Involves carefully cutting out the endometrial tissue, aiming to remove the entire lesion down to healthy tissue. This method is favored for deeper lesions and provides tissue for biopsy confirmation.
Ablation: Uses heat, electricity, or other energy sources to destroy the surface of the endometrial implants. While effective for superficial lesions, ablation may not fully address deeper, infiltrative endometriosis, as it only targets the visible surface.
Surgical removal of lesions can significantly reduce pain and may improve fertility outcomes. Supportive therapies like pelvic floor physical therapy, dietary changes emphasizing anti-inflammatory foods, and stress management techniques like yoga or mindfulness can complement medical and surgical treatments to manage symptoms and improve overall well-being.