Investigations

The purpose of the investigations is to establish the underlying cause and to rule out the possibility of dual pathology accounting for the symptom. Routine infection screening such as complete blood count, inflammatory markers, urinalysis, or mid-stream urine for culture and sensitivity are performed at the initial stage.

Ultrasonography

Ultrasonography is a very useful investigation in women with CPP. It can detect many structural pelvic pathology such as uterine fi­broids, adenomyosis, ovarian cysts, and hydrosalpinx. However, pelvic ultrasonography may be normal in women with endomet­riosis or pelvic adhesions. The use of transvaginal ultrasonog­raphy to diagnose adenomyosis and pelvic congestion syndrome requires special expertise. The characteristic ultrasound features of adenomyosis are summarized in Box 44.2 (9). It is now recog­nized that transvaginal ultrasound has a sensitivity between 53% and 89% and a specificity of 50-99% in diagnosing adenomyosis (9). Doppler ultrasound may further help in distinguishing uterine

Box 44.2 Ultrasound features of adenomyosis

• Globularly enlarged uterus

• Asymmetrical myometrial thickening

• Poorly defined, irregular thickened junctional zone

• Linear striations

• Myometrial cysts (anechoic roundish area of 1-7 mm)

• Adenomyoma: ill-defined nodular heterogeneous myometrial mass

Source data from Dueholm M. Transvaginal ultrasound for diagnosis of adenomyosis: a review. Best Practice & Research Clinical Obstetrics and Gynaecology Vol. 20, No. 4, pp.

Levy G, Dehaene A, Laurent N, et al. An update on adenomyosis. Diagn Interv Imaging 2013;94:3-25.

Box 44.3 Indications for laparoscopy in women with chronic pelvic pain

• Past history or history suggestive of:

— endometriosis with moderate to severe dysmenorrhea, dyspareunia

— previous pelvic inflammatory disease

— previous pelvic or abdominal surgery

— ovarian remnant syndrome.

• Underlying cause of pain remains unexplained despite thorough investigation.

• Persistent pain despite medical treatment.

• Suspicion of adnexal mass or other pelvic pathology.

fibroids from adenomyosis: fibroids often have well-defined rim with few vessels entering the body of the mass while adenomyosis have vessels running perpendicularly into the adenomyoma (9). The use of three-dimensional ultrasound permits a better visualization of the junctional zone in the coronal view and so improves the diag­nostic accuracy of adenomyosis compared with two-dimensional ultrasound (21).

Transrectal ultrasonography is particularly useful in assessing le­sions in the rectovaginal septum and should be offered to women with symptoms and signs indicative of deep infiltrating endometri­osis. Hypoechoic thickening of the torus and uterosacral ligament are often found in deep infiltrating endometriosis (22).

Ultrasound soft markers such as ovarian mobility, probe ten­derness, and pouch of Douglas obliteration may help to assess the severity of endometriosis. These soft markers have been used to de­velop an ultrasound-based endometriosis staging system (UBESS) to help predict the level of complexity of laparoscopic surgery of endo­metriosis. The presence of soft markers on ultrasound improved the probability of positive findings on diagnostic laparoscopy from 58% to 73% and may help to identify women who may benefit from it (23).

Laparoscopy

Laparoscopy remains the gold standard for diagnosing the un­derlying cause of CPP. In one series, up to 40% of the indica­tions for laparoscopy performed by gynaecologists were CPP (3).

It is helpful to remember that the stage of endometriosis does not correlate with the severity of pain experienced by women. Many women with severe endometriosis may experience little pain; whereas some women with minimal or mild endometriosis may be troubled with severe pain.

Laparoscopy provides an opportunity not only for diagnosis but also treatment at the same setting. Moreover, laparoscopy itself has been shown to have a placebo effect and the reassurance of a negative laparoscopy may improve pain in 30% of the patients, independent of the severity of their disease (24).

However, laparoscopy is not without risks. The procedure is asso­ciated with deaths in approximately 3-8 in 100,O0O cases and injury to the bowel, bladder, or major blood vessels in 2 in 1000 cases (25). Not everyone presenting with CPP requires a laparoscopy. The de­cision to proceed with laparoscopy should be made after a careful, individualized assessment, depending partly on how likely there is to be pathology in the pelvis and partly on the response to expectant treatment. Box 44.3 highlights some of the situations when lapar­oscopy is suggested. In an earlier series, around 40% of the patients with CPP undergoing laparoscopy had negative findings and some of the positive findings may be coincidental and not necessary be the underlying cause of the CPP (3). A negative laparoscopy, however, may indicate that non-gynaecological causes of the CPP are more likely. A video recording or photographs should be taken during the laparoscopy, as they may be useful during explanation to the patient about her condition and in planning future treatment plans.

Laparoscopic pain mapping

Patient-assisted laparoscopy has been attempted to improve iden­tification of potential sources for CPP. The procedure is performed under conscious sedation and local analgesia by probing and trac­tion of tissue to try and reproduce the patient's symptoms.

10. Local anaesthetics can be injected at tender sites and the response recorded. A prospective cohort study showed that overall 74% of pa­tients felt that their symptoms had improved after treatment based on findings at pain mapping (27). Further randomized controlled trials (RCTs) with long-term outcome are required to evaluate the role of laparoscopic pain mapping.

Hysteroscopy

Hysteroscopy has a limited role in the diagnosis of CPP. It per­mits direct visualization of the uterine cavity and may be useful in establishing the diagnosis of adenomyosis. Hysteroscopic findings of irregular endometrium with endometrial defects, hypervascularization, or strawberry pattern or cystic haemorrhagic lesions have been associated with adenomyosis (28). Hysteroscopy also enables visually guided myometrial biopsy for confirmation of the diagnosis.

Pelvic venography

Pelvic venography is the gold standard diagnostic test for pelvic congestion syndrome. It provides assessment of the anatomy of the pelvic veins and allows measurements of venous diameters, venous functions, and grading of the venous plexuses to be made. A scoring

system was devised to grade the severity of pelvic venous conges­tion; a score of 6 is considered diagnostic for pelvic congestion. This scoring system has a diagnostic sensitivity of 91% and specificity of 89% (29). Dihydroergotamine (DHE), a selective venoconstrictor, has been used previously to cause vasoconstriction of the pelvic vein to reduce pelvic congestion syndrome and has been postulated to have diagnostic and therapeutic value in a previous study.

Cystoscopy

Cystoscopy should be considered if the CPP is associated with urological symptoms. It is useful in diagnosing interstitial cystitis, bladder stones, granulomatous inflammation, and urological neo­plasms. After cystodistension, the bladder is inspected systemat­ically including the trigone and urethral openings. The degree of hyperaemia, trabeculation, and status of the mucosa are carefully examined. Hunners ulcers are classic features of interstitial cystitis. They are circular areas of reddened bladder mucosa with small ves­sels radiating toward a central pale scar. These ulcers may rupture during bladder distension causing haemorrhage. Treatment with fulguration with diathermy or laser, resection, or submucosal injec­tion with steroid can be performed during the time of cystoscopy. However, these ulcers represent the most severe form of interstitial cystitis and may only be found in 5-10% of the patients. Other sus­picious ulcers should always be biopsied to rule out malignancy. Glomerulations (petechial haemorrhages in bladder lining) after hydrodistension is no longer considered to be pathognomonic for interstitial cystitis and is of limited diagnostic value (31).

Others investigations

Computed tomography and MRI are occasionally required. It should be considered when ultrasonography is equivocal or not diagnostic. MRI can help delineate soft tissue better and may be useful in cases of suspected adenomyosis.

Box 44.4 MRI features of adenomyosis

• Globular enlarged uterus with smooth contour

• Asymmetrical myometrial thickening

• Thickening of the junctional zone, with a thickness of at least 12 mm

• Largest junctional zone thickness-to-total myometrium ratio greater than 40-50%

• An ill-defined area of low signal intensity in the myometrium on T2-weighted MRI

• Islands of ectopic endometrial tissue identified as punctate foci of high signal intensity on T1-weighted image

Source data from Dueholm M. Transvaginal ultrasound for diagnosis of adenomyosis: a review. Best Practice & Research Clinical Obstetrics and Gynaecology Vol. 20, No. 4, pp. 569-582,2006.

Levy G, Dehaene A, Laurent N, et al. An update on adenomyosis. Diagn Interv Imaging 2013;94:3-25.

in those patients who have metal implants in the body or those who are claustrophobic. Hormonal tests may sometimes be helpful, for example, the finding of low follicle-stimulating hormone level or high oestradiol level typically found in the premenopausal range is consistent with ovarian remnant syndrome in women who have undergone bilateral oophorectomy. Improvement of pain after in­jection of local anaesthetics to trigger points or scars may be useful in diagnosing myofascial pain syndrome or nerve entrapment conditions.