Introduction to Pelvic PainImaging StrategiesAuthor Siripanth Nippita MS 4 Editor Ashley Davidoff MD copyright 2007
Pelvic pain is a common gynecological complaint and can be broadly classified as acute, cyclic, or chronic. Acute pelvic pain is intense, characterized by sudden onset, sharp rise, and relatively short course. It is often accompanied by nausea, vomiting, diaphoresis, fever or leukocytosis. Cyclic pain is associated with menses. Chronic pelvic pain persists for greater than six months? duration and, unlike acute pain, is not associated with autonomic reflex responses.
Clinical Considerations Pelvic inflammatory disease
Acute pain Ectopic pregnancy Adnexal torsion Leaking/ruptured ovarian cyst Pelvic inflammatory disease/tubo-ovarian abscess Degenerating uterine fibroid Endometriosis Postoperative/postpartum complications Ovarian vein thrombosis Endometritis (May also consider including appendicitis, diverticulitis, and bowel obstruction scenarios here)
Cyclical PainEndometriosis Adenomyosis Intrauterine device Chronic pain Endometriosis Adhesions Pelvic congestion/pelvic varices Ovarian remnant syndrome Uterine fibroids
Delays in diagnosing the cause of acute pelvic pain may increase morbidity and mortality, particularly for patients with ectopic pregnancy or adnexal torsion. In ectopic pregnancy, pain is caused by acute dilation of the fallopian tube. It may abate if the tube ruptures. As hemoperitoneum develops, the pain may become generalized over the abdomen and pelvis.
Pain secondary to adnexal torsion may be severe and constant, or intermittent. Associated vomiting is also common. Other non-gynecologic etiologies requiring emergent treatment include appendicitis, diverticulitis, and bowel obstruction. Leaking or ruptured ovarian cysts, endometriosis, degenerating fibroids, or pelvic inflammatory disease also cause acute pain.
Primary and secondary dysmenorrhea cause cyclic pain. Primary dysmenorrhea is menstrual pain without pelvic pathology, usually with onset around the time of menses and resolving within 48-72 hours. The diagnosis is made by confirming its cyclical nature and ruling out underlying causes such as pelvic inflammatory disease; uterine, cervical or vaginal abnormalities; endometriosis; and adenomyosis. Patients with primary dysmenorrhea have normal pelvic exams. Pain associated with secondary dysmenorrhea starts 1-2 weeks before menses and can persist for days after bleeding stops. Common causes include endometriosis, intrauterine devices, and adenomyosis (ingrowth of the endometrium into the uterine musculature).
The etiology of chronic pelvic pain may be gynecologic, GI-related, musculoskeletal, neurologic or urologic, or multi-factorial. Psychologic factors related to trauma or sexual abuse can also play a role. A detailed history and associated differential diagnosis are essential in choosing which imaging studies to undertake.
Imaging StrategiesIn general, ultrasonography is the first investigative study of choice if a gynecologic problem is suspected. It allows for good visualization of the pelvic organs, is relatively inexpensive, and does not expose the patient to ionizing radiation. The use of a transvaginal probe also obviates the need for a full bladder.
Other studies used in the evaluation of pelvic pain include sonohysterography. Sterile saline is injected into the uterine cavity, and transvaginal ultrasound is used to evaluate the endometrial cavity. Polyps, submucosal fibroids, and endometrial cancer may be delineated.
CT is of use in several clinical situations. It may be performed if ultrasound findings are equivocal, if the abnormality is beyond the field of a transvaginal probe, or if a non-gynecologic cause of pelvic pain is suspected. CT is particularly important in evaluating suspected pelvic abscesses or hematomas, postpartum complications, complications related to pelvic inflammatory disease, or to exclude bowel disease.
MRI allows for excellent visualization of soft tissue structures with multiplanar views. It is helpful for diagnosing endometriosis and determining the origins of adnexal masses. It is the best imaging modality to diagnose adenomyosis and distinguish it from uterine fibroids. It may also demonstrate pelvic varices/venous congestion, though there is scant data evaluating accuracy, sensitivity and specificity.
Hysterosalpingography (HSG) involves injecting radiopaque contrast through the cervix and using fluoroscopy to visualize the uterine cavity and fallopian tubes. It evaluates tubal patency and may delineate subtle distortions in the uterine cavity by polyps or other small masses. HSG is commonly used for infertility evaluation, and may also be considered for chronic pelvic pain.
References:
Bennett GL. Slywotzky CM. Giovanniello G. Gynecologic causes of acute pelvic pain: spectrum of CT findings. Radiographics. 22(4):785-801, 2002 Jul-Aug. Cody RF Jr, Ascher SM. Diagnostic value of radiological tests in chronic pelvic pain. Best Practice & Research in Clinical Obstetrics & Gynaecology. 14(3):433-66, 2000 Jun. Okaro E, Condous G. Diagnostic and therapeutic capabilities of ultrasound in the management of pelvic pain. Current Opinion in Obstetrics & Gynecology. 17(6):611-7, 2005 Dec. Okaro E. Valentin L. The role of ultrasound in the management of women with acute and chronic pelvic pain. Best Practice & Research in Clinical Obstetrics & Gynaecology. 18(1):105-23, 2004 Feb.
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