Causes, classification and clinical features of chronic pelvic pain

It is said that being a woman is difficult, and life is even more difficult for women with chronic pelvic pain. The onset of chronic pelvic pain will have a great impact on women's bodies and will directly affect the quality of their lives. In particular, chronic pelvic pain caused by some gynecological diseases will bring more gynecological diseases to women. Therefore, women with chronic pelvic pain must receive timely treatment.

The harm of chronic pelvic pain can be said to be long-lasting. There are periodic pains, as well as unexplained abdominal pain, back pain and other problems. The following are some common sense questions about chronic pelvic pain, which I hope will be helpful to patients with chronic pelvic pain. .

Chronic pelvic pain refers to a group of diseases that occur in the female pelvis, abdomen, lumbosacral region or buttocks and last for more than 6 months, often causing functional disability or requiring drug or surgical treatment.

1. The causes of chronic pelvic pain are complex , including gynecological and non-gynecological causes. The main gynecological causes include endometriosis, pelvic adhesions, pelvic inflammation, pelvic venous congestion syndrome, adenomyosis, residual ovary syndrome, etc.; the main non-gynecological causes include interstitial cystitis, irritable bowel syndrome, abdominal wall and pelvic myofascial pain trigger points, fibromyalgia pain syndrome and pelvic floor pain syndrome.

2. The diagnosis of chronic pelvic pain mainly relies on medical history and physical examination , as well as necessary auxiliary examinations.

3. Chronic pelvic pain with clear causes can be treated according to the causes , with definite curative effects. Chronic pelvic pain with unknown causes or obvious symptoms but no obvious pathological changes, or obvious pathological changes but mild symptoms, is more difficult to treat. Currently, commonly used treatment methods include drug therapy (Chinese and Western medicine), psychotherapy, surgical treatment, and physical therapy.

Chronic pelvic pain (CPP) is a common disease in women and directly affects the quality of life of patients. The exact incidence of chronic pelvic pain is still unclear. Literature reports that 15% to 20% of women of childbearing age suffer from chronic pelvic pain for more than one year. The causes of chronic pelvic pain are not entirely gynecological and obstetric diseases, but also include diseases of other systems such as the urinary system, digestive system, skeletal muscles, and mental and nervous systems.

CPP can be the result of one or more factors, so the clinical manifestations are diverse and difficult to diagnose. In the United States, only about 10% of CPP patients visit obstetricians and gynecologists. According to statistics, 80% of CPP patients are diagnosed with endometriosis and receive corresponding treatment during their first visit. Among them, 54% of patients still have pain after treatment, and 18% of patients choose hysterectomy due to unbearable pain or recurrent pain. However, 5% to 26% of patients still have pelvic pain after hysterectomy. Therefore, the diagnosis and treatment of chronic pelvic pain is a hot and difficult issue in the field of obstetrics and gynecology.

I. Definition

Pain is an unpleasant sensory or emotional experience caused by actual or potential tissue damage. Pain is a subjective feeling. Many patients complain of pain but lack evidence of tissue damage and pathological support. This type of pain may be related to neuropsychiatric factors. There is currently no unified and accurate definition of chronic pelvic pain. In the field of gynecology, most scholars consider pain duration of more than 6 months as a necessary condition for diagnosing chronic pelvic pain. In fact, a complete definition of chronic pelvic pain should at least include the following points: the characteristics, location and severity of the pain. The most commonly used definition of chronic pelvic pain in the domestic obstetrics and gynecology community is: non-cyclical pain in the lower abdomen or pelvis that lasts for at least 6 months and is ineffective against non-opioid analgesics. According to this definition, the lower abdomen and pelvis are the sites of pain, but many scholars also classify vulvar pain into the study of chronic pelvic pain. The definition of chronic pelvic pain recommended by ACOG (2004) is: non-cyclical pain in the pelvis, anterior abdominal wall (periumbilical or subumbilical), lumbosacral region, or buttocks, lasting for more than 6 months, often causing functional disability or requiring drug or surgical treatment. The absence of positive findings during physical examination cannot rule out the severity of the patient's pain, and normal examination results cannot rule out the presence of pathological changes in the pelvis.

Classification of chronic pelvic pain

There are many classifications of chronic pelvic pain, which can be divided into gynecological and non-gynecological causes based on the cause. According to the pathogenesis, it is divided into 1. Pain caused by inflammation (including pain caused by biological and chemical inflammation), 2. Pain caused by vascular lesions (including vasospasm, vascular stenosis occlusion and embolism, etc.), 3. Pain caused by immune diseases, 4. Pain caused by endocrine diseases, 5. Pain caused by metabolic diseases (including bone pain caused by calcium and phosphorus metabolism disorders), 6. Pain caused by abnormal nerve function, and 7. Pain caused by psychogenic diseases. Classification by manifestation: 1. Localized pain; 2. Radiating pain; 3. Referred pain, etc. Currently, etiological classification is widely used.

Clinical features of chronic pelvic pain

The clinical manifestations of chronic pelvic pain caused by different causes are described below.

(I) Gynecological causes

Gynecological diseases that can cause chronic pelvic pain mainly include endometriosis, pelvic and abdominal adhesions, chronic pelvic inflammatory disease, pelvic venous congestion syndrome and pelvic benign and malignant tumors.

1. Endometriosis: It is the most common cause of chronic pelvic pain. It is reported that approximately 79% of patients with endometriosis have different types of pelvic pain, including dysmenorrhea and dyspareunia. Approximately 74% to 83% of patients with chronic pelvic pain have been shown to have endometriosis. Because the clinical symptoms of pelvic pain in patients are atypical, or there are severe pain symptoms but no clear pathological examination results to support it, the specific correlation between endometriosis and CPP is still unclear. The study found that more than half of patients with CPP symptoms were diagnosed with endometriosis. Severe dysmenorrhea is related to repeated microbleeding in the ectopic implant lesions and the resulting adhesion lesions. Pathophysiological and histological studies have found that deep infiltrating endometriotic lesions lead to the appearance of severe CPP symptoms. Analysis of the cause may be related to the compression and infiltration of the subperitoneal pelvic endometriotic lesions on the nerves. The pain caused by the presence of endometriotic lesions often occurs in specific anatomical locations (such as the uterosacral ligaments and the rectouterine peritoneum), leading to deep dyspareunia, defecation pain, and pelvic organ dysfunction. Studies have shown that the nutritional support of sensory and sympathetic nerves in patients with endometriosis is related to the development of ectopic lesions. The percentage of severe pain associated with deep endometrial implants in areas with dense nerve plexuses (particularly the uterosacral region) is much higher than that associated with pain associated with other types of implants. A positive study showed that the trophic effect of sensory and autonomic nerves on ectopic implants and the potential changes in estradiol levels regulate the functional activities of the central nervous system.

Dysmenorrhea is the primary symptom of endometriosis. The typical manifestation is secondary dysmenorrhea that gradually worsens. The dysmenorrhea often occurs in the lower abdomen, lumbosacral region, or lumbo-anal region. The symptoms weaken or disappear after menstruation. When the lesion is more serious, symptoms such as heaviness and pain in the lower abdomen and lumbosacral area may occur during the non-menstrual period, and worsen during menstruation. Due to the different locations of endometriosis, the mechanisms that cause pain are also different. Pelvic endometriosis is mainly caused by repeated endometrial bleeding, which leads to edema of surrounding tissues and inflammatory reactions, causing pain; endometriosis in the myometrium causes congestion and swelling of the myometrium due to bleeding and blood retention, and increased tension of the uterine serosa, causing pain. Most researchers believe that the occurrence and severity of CPP symptoms have no significant correlation with the stage of endometriosis.

2. Pelvic and abdominal adhesions: Adhesions are adjacent tissues and organs adhered together by fibrous tissue and cause structural abnormalities. Pelvic pain caused by adhesions accounts for about one-third of chronic pelvic pain. Adhesions can be caused by pelvic inflammatory disease, endometriosis, and after pelvic gynecological surgery. About 25% of patients with chronic pelvic pain are diagnosed with abdominal or pelvic adhesions by laparoscopy. However, there is still controversy about the relationship between adhesions and chronic pelvic pain. The mechanism of pain caused by adhesions may be related to structural changes that restrict the normal activities and functions of the pelvic cavity and organs. When using laparoscopy to locate pain, it was found that simply touching the adhesion band rarely causes pain, but pain will occur when the adhesion band is pulled to create tension. Other studies have shown that some adhesions contain nerve tissue. The range and density of adhesions do not show a constant proportional relationship with the severity of pelvic pain. The characteristics of the adhesion band are related to the pain: when the adhesions are thickened, have obvious blood vessels, or even when the blood vessels are congested and dilated, it is more likely to cause pain. The pain is characterized by non-cyclical pain, chronic, persistent dull pain. Depending on the location of adhesion, it may manifest as abdominal pain, umbilical pain, lower abdominal pain or pain above the sacrum.

3. Pelvic inflammatory disease (PID): Acute pelvic inflammatory disease is the most common cause of pelvic pain. Including endometritis, adnexitis, pelvic connective tissue inflammation and pelvic peritonitis. About 18% to 35% of patients with acute pelvic inflammatory disease will develop chronic pelvic pain. Incomplete treatment of acute PID may lead to chronic pelvic inflammatory disease, hydrosalpinx and ovarian hydrops, pelvic adhesions, etc. Chronic pelvic inflammatory disease accounts for approximately 23% to 30% of chronic pelvic pain. The probability of PID causing chronic pelvic pain is 20%, while the probability of PID causing chronic pelvic pain more than three times is 67%. The mechanism by which pelvic inflammatory disease causes chronic pelvic pain may be related to the stimulation of inflammatory mediators, which leads to abnormal morphology and structure of the fallopian tubes, ovaries and pelvic cavity. The characteristics of chronic pelvic pain caused by pelvic inflammation are: persistent dull pain in the lower abdomen, heaviness and soreness in the lumbar region, which worsens during menstruation, after cold and fatigue. There may also be increased vaginal discharge, menorrhagia or vaginal bleeding.

4. Pelvic varicositiles and pelvic congestion syndrome (PCS): Due to the expansion of the pelvic venous plexus and blood stasis, the uterus and adnexal area will swell, congestion, and connective tissue hyperplasia. It is often manifested as dull pain or a feeling of heaviness in the lower abdomen, low back pain, extreme fatigue, dyspareunia, dysmenorrhea due to congestion, excessive leucorrhea, swelling and pain in the vulva and vagina or urethral symptoms, anal pain and autonomic nervous system dysfunction. The characteristic is that the pain is aggravated by prolonged standing or activity and relieved by bed rest. Deep dyspareunia is a common symptom in PCS patients, with an incidence rate of 71% to 78%.

Pelvic venous congestion is more common in women of childbearing age, with an average age of 33 years old. It may be related to active ovarian function, abundant blood supply, and defects in the elasticity or structure of the blood vessel wall, resulting in blood stasis and vasodilation. During pelvic venography, dilation of pelvic veins such as the ovaries and uterus can be seen, and the contrast agent is evacuated slowly.

B-mode ultrasound can demonstrate pelvic venous dilatation and congestion, but its sensitivity is not as high as pelvic venography. Laparoscopy can effectively diagnose pelvic venous congestion. However, due to the large differences in the diameters of pelvic veins and the lack of a definite value, the objectivity of laparoscopic diagnosis is limited.

5. Adenomyosis: The typical symptoms of adenomyosis are dysmenorrhea, lower abdominal pain and abnormal uterine bleeding. It starts with progressive dysmenorrhea and dyspareunia, which may gradually develop into non-cyclical pelvic pain. Gynecological examination revealed that the uterus was spherical and enlarged, generally not exceeding the size of 14 weeks of pregnancy, with a hard texture and tenderness.

6. Residual ovary syndrome: Residual ovary syndrome refers to a syndrome caused by a small amount of functional ovarian tissue remaining after hysterectomy and bilateral oophorectomy. The characteristics of pelvic pain are cyclical or frequent pain. Most of the time, it is dull pain, non-radiating pain in the lower abdomen or lumbar ribs or pain during sexual intercourse. A few are sharp knife-like pains. It can also manifest as difficult-to-explain irritable bowel syndrome or frequent and urgent urination.

7. Others: Fallopian tube contraception can cause pelvic adhesions, fallopian tube inflammation, and pelvic venous congestion syndrome, leading to pelvic pain. Artificial abortion causes adhesions of the cervix or uterine cavity, resulting in periodic pain and decreased menstruation; common infections after abortion include endometritis, adnexitis, and pelvic inflammatory disease, which can develop into chronic inflammation and cause pain if not thoroughly treated. An intrauterine device in the pelvis or abdomen can cause chronic pelvic pain.

Chronic pelvic pain can be said to be the most common gynecological disease that is most harmful to women's bodies. Here we hope that our article will be helpful to those female friends who are experiencing chronic pelvic pain, and at the same time remind all female friends to learn to take care of themselves in daily life.