Acute pelvic pain is generally considered to be pain that is of less than about 3 months duration. Patients with acute pelvic pain can be categorized into patients with a positive versus those with a negative preganacy test (beta-human chorionic gonadotropin). The objectives of this talk are to: 1) provide a scheme to understand the causes of acute pelvic pain, 2) triage the diagnostic imaging workup using the clinical presentation and laboratory data, 3) achieve a tailored differential diagnosis useful to guide appropriate treatment in female patients presenting with acute pelvic pain
For the pregnant patient, the more common causes of acute pelvic pain include preterm labor, ectopic pregnancy, miscarriage, hemorrhagic corpus luteum cyst, degenerating leiomyoma, ovarian torsion, retroplacental hematoma or placental abruption, placenta increta/percreta/accreta, uterine rupture, ovarian hyperstimulation, and, less frequently, gestational trophoblastic disease.
Postpartum Causes:
In the postpartum patient, endometritis, septic thrombophlebitis, retained products of conception, pelvic abscess, bladder flap hematoma are to be considered.
Gynecologic Causes:
In non-pregnant patients, the list includes Mittelschmerz (midcycle ovulatory pain), hemorrhagic ovarian or corpus luteum cyst, ovarian torsion, endometriosis, gynecologic neoplasm, degenerating leiomyoma, adenomyosis, renal stone with obstructive uropathy, pelvic congestion syndrome, pelvic arteriovenous malformation, premenstrual syndrome, and pelvic floor relaxation (including cystocele, rectocele, enterocele, and uterine prolapse), and inguinal and other hernias.
Infectious and inflammatory causes:
Causes of acute pelvic pain with fever include: pelvic inflammatory disease, gastroenteritis, diverticulitis, inflammatory bowel disease, appendicitis, and urinary tract infection.
Vaginal Bleeding:
Acute pelvic pain with vaginal bleeding can result from ectopic pregnancy, miscarriage, retroplacental hematoma or placental abruption, placental malpresentation, placenta increta/percreta/accreta, retained products of conception, uterine rupture, gestational trophoblastic disease, leiomyomas with or without degeneration, adenomyosis, pelvic inflammatory disease, gynecologic neoplasm, and pelvic arteriovenous malformation.
The Imaging Workup:
Pelvic ultrasound (US) is the study of choice in the initial evaluation of pregnancy presenting with acute pelvic pain. US can characterize the presence, number and location of fetuses (intrauterine versus ectopic), presence of abnormal placentation, retroplacental hemorrhage or abruption, an endometrial or myometrial defect with uterine rupture.
In women presenting with acute pelvic pain without pregnancy, US is the first line modality for evaluation. US is widely available, noninvasive and has no ionizing radiation. It is essential that the clinical history, physical findings, hormonal status of the patient and laboratory data be correlated with the US findings to arrive at the best differential diagnosis. Not only the pregnancy test, but also the duration and pattern of the pain, date of the last menstrual cycle, association with vaginal bleeding, and findings of fever and leukocytosis must be correlated. The negative predictive value of pelvic US in patients with acute pelvic pain has been reported as high as 70 % (Harris et al) to 92% (Barloon et al).
The most common cause of acute pelvic pain in these patient is pelvic inflammatory disease. In florid cases, US can demonstrate the findings of tuboovarian complex, hydro and/or pyosalpinx, abscess, and associated findings of peritonitis. However, most cases are diagnosed clinically. If complicated by severe or confusing signs and symptoms, US can be performed, reserving computed tomography (CT) for cases that are refractory to medical therapy. CT or US can be used for planning treatment for abscess drainage percutaneously if needed.
Ovarian torsion can be a difficult diagnosis to make, but is manifested by an enlarged ovary with peripheral follicles. A cyst or mass as a lead point is found in most adult patients. A twisted vascular pedicle, uterine displacement to the affect side on CT or magnetic resonance imaging (MRI), thickening of the fallopian tube can be signs of ovarian torsion. Color and pulsed Doppler US evaluation reveals the ovary has occluded venous flow and varying degrees of impaired high resistance or occluded arterial inflow depending on the amount of “twist” or rotation of the vascular pedicle. Due to the risk of necrosis and gangrene of the ovary, ovarian torsion is a surgical emergency.
Physiologic cysts, whether luteal or follicular, commonly cause acute pelvic pain. These lesions are usually well evaluated by pelvic US and can be managed by short-term interval follow-up with repeat US in 2 or 3 months.
Gastroenteritis, diverticulitis, appendicitis, septic thrombophlebitis, pyelonephritis and urinary tract infection may mimic obstetric and gynecologic emergencies. These conditions may be evaluated by pelvic US, followed by CT or MRI for problem solving and for acute presentation with fever, leukocytosis, right lower quadrant pain, and hematuria. CT is particularly valuable to evaluate suspected abscess or hematoma, pelvic inflammatory disease, postpartum complications, and suspected bowel disease. CT or MRI can be used in cases with equivocal US findings, cases with the abnormality extending beyond the field of view on transvaginal US, or for further tissue characterization with complex lesions. Noncontrast helical CT is the study of choice for suspected urinary tract stones.
MRI is a useful problem solving technique as an adjunct to initial US for acute gynecologic disease. MR has high tissue contrast, excellent resolution, multiplanar imaging capabilities, and lacks ionizing radiation. MR provides tissue characterization for endometriosis, hemorrhagic cysts, dermoid cysts, ovarian torsion, arteriovenous malformation, degenerating fibroids, and placenta increta/percreta/acreta. Comprehensive MR imaging requires use of chemical shift imaging or fat suppression, and understanding of tissue signatures by correlating the T1 weighted and T2 weighted scans for detection and characterization of these conditions.
Conclusions:
Patients with acute pelvic pain may have characteristic findings on US, CT, and MRI that permit specific diagnosis of their conditions. Becoming familiar with these patterns on cross sectional imaging empowers the radiologist to identify the cause of the pain and aid the referring clinicians to institute prompt and appropriate treatment for these important and sometimes life-threatening conditions.
Suggested Reading:
1. van Breda Vriesman AC, Puylaert JBCM, Mimics of appendicitis: alternative nonsurgical diagnosis with sonography and CT. Am J Roentgenol 86: 1103 – 1112, 2006
2. Birchard KR, Brown MA, Hylsop WB, et al, MRI of acute abdominal and pelvic pain in pregnant patients. Am J Roentgenol 184: 452 – 458, 2005
3. Kuligowska E, Deeds L, Kang L, Pelvic pain: overlooked and underdiagnosed gynecologic conditions. RadioGraphics 25:3 – 20, 2005
4. Siddall KA, Rubens DJ, Multidetector CT of the female pelvis. Radiol Clin N Am 43:1097 – 1118, 2005
5. Okaro E, Valentin L, The role of ultrasound in the management of women with acute and chronic pelvic pain. Best Practices & Research in Clinical Obstetrics and Gynecology 18:105 – 123, 2004
6. Gottleib RH, La TC, Erturk EN, et al, CT in detecting urinary tract calculi: influence on patient imaging and clinical outcomes”, Radiology 225:441-449, 2002
7. Rha SE, Byun JY, Jung SE, et al, CT and MR imaging features of adnexal torsion. RadioGraphics 22:283-294, 2002.
8. Bennett GL, Slywotzky CM, Giovanniello G, Gynecologic causes of acute pelvic pain: spectrum of CT findings. RadioGraphics 22:785-801, 2002.
9. Kamel IR, Goldberg SN, Keogan MT, et al, Right lower quadrant pain and suspected appendicitis: nonfocused appendiceal CT – review of 100 cases. Radiology 217:159-163, 2000.
10. Harris RD, Holtzman SR, Poppe AM, Clinical outcome in female patients with pelvic pain and normal pelvic US findings. Radiology 216:440-443, 2000.
11. Urban BA, Fishman EK, Tailored helical CT evaluation of acute abdomen. RadioGraphics 20:725-749, 2000.
11. Dohke M, Watanabe Y, Okumura A, et al, Comprehensive MR imaging of acute gynecologic diseases. RadioGraphics 20:1551-1566, 2000.
12. Kaakaji Y, Nghiem HV, Winter TC, Sonography of obstetric and gynecologic emergencies: Part I, Obstetric Emergencies. Am J Roentgenol 174:641-649, 2000.
13. Kaakaji Y, Nghiem HV, Winter TC, Sonography of obstetric and gynecologic emergencies: Part II, Gynecologic Emergencies. Am J Roentgenol 174:651-656, 2000.
14. Rosen MP, Sands DZ, Longmaid HE, et al, Impact of abdominal CT on the management of patients presenting to the emergency department with acute abdominal pain. Am J Roentgenol 174: 1391 – 1396, 2000
15. Damani N, Wilson SR, Nongynecologic applications of transvaginal US. RadioGraphics 19:S179-200, 1999.
16. Barloon TJ, Brown BP, Abu-Yousef MM, et al. Predictive value of normal endovaginal sonography in excluding disease of the female genital organs and adnexa. J Ultrasound Med 13:395-398, 1994.
