Chapter 4. Pelvic Pain and IUD Position

Women’s Point of Care Ultrasound

Welcome to the Section on Pelvic Pain and IUD position. One of the primary reasons for performing a point of care ultrasound in women is to determine the source of pelvic pain. Pelvic pain is one of the most common reasons that women present to a provider or a hospital. Since some of the conditions causing acute pelvic pain can be life-threatening or cause significant morbidity, rapid detection and clinical decision-making (is critical. This chapter will review some of the common causes of pelvic pain detectable by point of care ultrasound. However, in the case of pelvic pain, it is even more important to have review or consultation by a sonographer, physician, or radiologist to confirm the diagnosis. To reiterate, The role of the clinician performing POCUS is to make a rapid assessment so the appropriate consult or referral can be made.

This chapter is NOT an exhaustive review of all indications for ultrasound evaluation for pelvic pain. It instead gives an overview of the most common conditions that can be assessed by a clinician using POCUS. The role of the clinician is to make rapid assessment for expedited care.

Objectives

By the completion of this Section the participant will be able to:

1.Describe the most common causes of female pelvic pain that can be evaluated by ultrasound

2.Recognize sonographic signs of pelvic abnormalities causing pelvic pain

3.Describe sonographic signs of an appropriately-placed IUD, as well as a malpositioned IUD

Acute pelvic pain

The conditions causing pelvic pain are divided into three general categories: Gynecologic, Obstetric, and Non-Gynecologic (bowel or bladder, for example). GYN conditions that can be evaluated by ultrasound will be described in this chapter.

Gynecologic causes:

1. Large or ruptured ovarian cysts – reviewed in the previous chapter

2. Ovarian torsion (twisting of the ovary)

3. PID – Pelvic inflammatory Disease (causing enlarged or dilated tubes)

4. Fibroids changing in size or with interruption of blood flow

5. Malpositioned IUD

Endometriosis. endometriosis is not diagnosed with ultraosund; but is presumed an ovarian endometrioma is seen

Obstetric causes – Discussed in greater detail in the First Trimester Course

1. Ectopic pregnancy

2. Threatened/spontaneous ab

Non-gynecologic causes:

Bowel
Bladder
Pelvic floor dysfunction

These typically require other forms of imaging (more advanced ultrasound or CT scans) or surgical investigation, and will not be presented in this course.

IMPORTANT NOTE: Every woman of childbearing age with pelvic pain MUST have pregnancy ruled out before assuming that pelvic pain is from another cause.

Figure 1. Summary of acute pelvic pain differential diagnosis list.

COMMON CAUSES OF PELVIC PAIN

Figure 1 lists the more common causes of pelvic pain. The conditions in this chapter detectable by ultrasound are:

1. Ovarian cyst

2. Dilated fallopian tube

NOTE: Adhesions, or scar tissue (along with endometriosis) cannot be visualized by ultrasound. Sometimes adhesions may be suspected if during a transvaginal ultrasound the ovaries and other organs do not “slide” or move when probed (sliding sign), or if probing those areas elicits pain.

Figure 2. Anatomic illustration of common causes of pelvic pain.

3. Ovarian torsion:

Ovarian torsion is one of the few gynecologic emergencies; it requires prompt attention, especially when it occurs during pregnancy.¹ Torsion can happen when any structure on a stalk becomes twisted on that stalk. Even a pedunculated fibroid can become torsed. If an ovary becomes torsed it is usually due to being enlarged, such as in the presence of a large cyst or mass.^2,3 Once that twisting occurs, the circulation to that ovary becomes diminished or completely cut off, and the ovary and surrounding tissue become ischemic and inflamed, causing intense pain. Women very often present with acute onset of intense pelvic pain that is on one side, and the pain is so intense it elicits nausea and vomiting. If the ovary is not rescued with a surgical intervention, she may lose function in that ovary.

An ultrasound may be helpful to investigate this. Classic sonographic signs are: little or no blood flow into the ovary, an enlarged ovary, follicles pushed to the periphery of the ovary, and fluid around the ovary or in the cul-de-sac (example in Figure 3). Even if these signs are not easily seen on ultrasound, the woman’s symptoms should be sufficient for you to consult or refer her for more advanced care.

Figure 3. Description and images of ovarian torsion. Images 1-2

4. Salpingitis or PID (Pelvic Inflammatory Disease)

Women with salpingitis, or inflamed tubes, often have a slow onset of symptoms, feel generally ill, and may have a fever. They also may present with increased vaginal discharge, or other symptoms of sexually transmitted infection, such as enlarged inguinal nodes.

Use of ultrasound can allow you to see if the tube or tubes are enlarged and determine if infection may be the cause.

Figure 4. Description and illustration of salpingitis or PID.

PID³

When performing the ultrasound, look for an elongated structure that appears fluid filled. It can often appear crimped, like a “link sausage”. You may see it as a circular cystic structure, but when you rotate on it, it then elongates. If it does not elongate when rotating the probe, it may not be the tube, but rather an ovarian cyst or blood vessel. To determine that the tubular structure is not a blood vessel, turn on color flow; absence of blood flow indicates that it is the tube and not a blood vessel.

Hydrosalpinx contains clear, serous fluid dilating the tube.

Pyosalpinx demonstrates more internal echoes, indicating pus in the fluid. Pyosalpinx is a common finding in salpingitis, or infection of the tube associated with PID

These are both demonstrated in Figure 5 below.

The uterus may also exhibit changes in PID, such as enlargement, thickening of the endometrium, fluid in the endometrium, and blurring of the endometrial/myometrial junction. This is in response to endometritis, which can precede salpingitis.²

Figure 5. Images demonstrating fluid-filled dilated fallopian tubes and the different echogenicity of clear fluid versus pyogenic material (pus). Images 3-4

Fibroids

Fibroids may cause pain or cramping in some women, while others are asymptomatic.

Fibroids may become unstable due to the influence of fluctuating hormones::

1. Can increase in size

2. Can decrease in size

3. Can degenerate, becoming ischemic and causing pain (described in Figure 6 below)

Ultrasound findings of unstable fibroids:

1. Structure and location consistent with fibroid

2. Internal mixed echogenicity

3. Possible decrease in blood flow

Figure 6. Description and image of degenerating fibroids. Image 5

Malpositioned IUD

Many women use an Intrauterine Device (IUD) for contraception very successfully

IUD complications most often arise from forces within the uterus itself; a small percentage are from problems with insertion.⁴

Complications women may experience:

1. Complete expulsion of the IUD

2. Perforation of the IUD through the uterine wall

3. Partial perforation or embedding into the uterine wall

4. Displacement of the IUD

5. Rotation of the IUD

6. Migration toward the cervix

One study of over 1000 IUD insertions reported an incidence of 16.6% malposition, with 8.8% requiring removal.⁵ It is reasonable to assume that in a population of women with a high usage rate of IUDs, that there would be a greater need for POCUS evaluation of IUD placement.

Figure 7. Description of malpositioned IUD

Identification of IUD^2,3

Although the use of ultrasound for routine IUD placement is not a standard practice, there are several reasons to use it before, during, and after IUD placement.

Ultrasound can be useful prior to IUD placement in identifying structural abnormalities felt on pelvic exam, helping to make the decision whether IUD placement is feasible, or may be difficult. For example, inserting an IUD into an acutely retroflexed uterus requires some extra care and skill. In addition, it is not possible on pelvic exam to know if a submucosal fibroid could be present, obstructing access to the upper endometrial canal.

POCUS assessment of the uterine cavity can be done for the following:

1. difficult insertion

2. IUD string not seen on clinical exam

If an IUD is not seen on a POCUS in a woman with a known IUD, a complete pelvic ultrasound and/or abdominal imaging is necessary to determine if the IUD has either been expelled, or if the IUD has perforated into the abdomen.

Figure 8. Tips for imaging an IUD and coronal image of IUD in the endometrium. Image 6

The IUD is easily recognized when using an ultrasound, but more easily recognized with a transvaginal ultrasound.

In a long view, the IUD should be seen in the mid to upper endometrial cavity, central to the cavity, in a vertical position tandem to the endometrium

The top of the IUD should ideally be within 5 mm of the inner fundus of the endometrial cavity

In a transverse view, you should see the wings or arms of the IUD extend outwardly toward the cornua, symmetrical and in relatively the same plane.

An IUD is considered malpositioned if it is situated in the cervix or lower uterine segment, if it is twisted or rotated, if the arms are not equally extended, if part of it is imbedded in the endometrium, or if it appears to have partially or completely perforated through the myometrium.

Figure 9. Identification of an IUD, ideal location, and types of malposition.

IUD Position -sagittal plane

The image in Figure 10. is a representation of how the arms of the uterus are identified in the transverse view using a transvaginal ultrasound.

Figure 10. Image of a correctly positioned IUD in a sagittal view of the uterus. Image 7

IUD Position - transverse plane

Figure 11 is a representation of how the arms of the uterus are identified in the transverse view using a transvaginal ultrasound

Figure 11. Illustration and images of identifying IUD position in the transerse view. Images 8-9

The IUD should be visualized in both the long or sagittal view, and the transverse view. This identifies position of the shaft and the extended arms.

The left image in Figure 12 below demonstrates the IUD is in the upper/mid uterus, parallel to the long axis of the uterus.

There is a bright echo along the shaft of the IUD, with a shadow behind it. This means that the sound has reflected directly back to the transducer, and that very little sound penetrated through the IUD. Sometimes it is the shadow that helps us to recognize the position of the IUD even more so than seeing the actual shaft.

The right image is a transverse view, showing that the arms are extended symmetrically at the fundus; this IUD is appropriately placed.

Figure 12. Illustration and images of IUD in ideal location and position. Images 10-11

Figure 13 is another long view of the uterus showing a good positioning of the IUD. Keep in mind that the strings can also be reflective, so they may appear as a bright line. However, they are too thin to cast a shadow. The presence of the shadow is then helpful to distinguish between the IUD and the string.

Figure 13. Image of an IUD identified in the sagittal view of the uterus, demonstrating echogenicity of the strings. Image 12

Identification of IUD - malposition

Examples of malpositioned IUDs are shown in Figure 14..

In the left image of Figure 14, the shaft of the IUD is in the middle of the uterine cavity, and the top is not near the fundus.

In the image on the right, you can see the IUD is more in the cervix than in the endometrium.

This position usually causes pelvic pain for the woman, since it is impinging into a sensitive area.

Figure 14. Image of sagittal views of uterus; left image showing the IUD in the mid uterus instead of at the fundus, right image showing the IUD impinging on the cervical canal. Images 13-14

Figure 15 shows an image is one where the IUD has rotated. One of the arms is pointed straight forward toward the anterior wall of the uterus, instead of pointing laterally into the cornua.

This means that the arm is no longer in the endometrium – it is imbedded in the anterior myometrium.

Figure 15. Image of sagittal view of the uterus demonstrating the IUD rotated so that the arm is extended anteriorly instead of laterally, and is embedded into the anterior myometrium. Image 15

Below in Figure 16 are 2D and 3D images of an IUD that is both low in the uterus (in the lower uterine segment) and twisted, as shown in the 3D image (circled).

Figure 16. Images of an IUD migrated downward into the cervical canal, confirmed by a 3D rendering. Images 16-18

Figure 17 is an enlargement of the 3-D image seen in Figure 16. The IUD itself is in the lower part of the uterus and impinging on the cervix. The arms are not extended outward – instead they are folded downward, causing them to embed into the sidewalls of the uterus (myometrium).

Figure 17. Enlargement of 3D rendering of IUD migrated into cervical canal with arms embedding into lower uterine segment. Image 17.

Summary - GYN IV Pelvic pain…

•Pelvic pain is one of the most common causes of women seeking medical care

•Pelvic pain has numerous etiologies, but many can be evaluated with ultrasound

• Ovarian Cysts

• Pelvic Inflammatory Disease

• Uterine Fibroids (leiomyoma)

• Ovarian Torsion

•Many women use an intrauterine device for contraception. However, there can be complications with IUD placement that can be evaluated by ultrasound. Symptoms of IUD expulsion or malposition include:

• Inability to feel or see IUD strings

• Pelvic pain

• Feeling the IUD extrude from the cervix

YOU MAY NOW TAKE THE QUIZ AND MOVE TO THE NEXT CHAPTER. YOU WILL NOT BE ABLE TO OPEN THE NEXT CHAPTER UNTIL YOU COMPLETE AND PASS THE QUIZ WITH 100%. YOU WILL HAVE AS MANY TRIES AS YOU NEED TO GET ALL THE ANSWERS CORRECT!

Women's Point-of-Care Ultrasound: Gynecology

Chapter 4. GYN IV. Pelvic Pain and IUD Position