Approach to acute pelvic pain (GYN): Clinical sciences

Acute pelvic pain is defined as pain that arises from the pelvic organs and structures and has been present for less than 3 months. It’s a common gynecologic problem that may require urgent evaluation and treatment, as in cases of ruptured ectopic pregnancy or adnexal torsion. Other, usually less urgent, gynecologic causes of acute pelvic pain include early pregnancy loss, primary dysmenorrhea, endometriosis, adnexal masses, and pelvic inflammatory disease.

Acute pelvic pain also can be secondary to intimate partner violence or assault. Finally, it may arise from non-gynecologic sources, such as the gastrointestinal tract, urinary tract, or musculoskeletal system.

When assessing a patient with acute pelvic pain, the first step is to assess their CABCDE to determine if they’re stable or unstable. If the patient is unstable, control hemorrhage; stabilize airway, breathing, and circulation; obtain IV access; and monitor vital signs. Then, perform a focused history and physical exam, obtain an hCG to assess for pregnancy, and get a pelvic ultrasound. A rapid bedside ultrasound might be necessary to avoid a delay in treatment.

Now, if the hCG test is positive, consider an ectopic pregnancy. The history may reveal syncope and vaginal bleeding, and physical exam might be positive for hypotension and tachycardia, as well as abdominal tenderness with rebound pain or guarding. If the ultrasound indicates an absence of an intrauterine pregnancy and possible free fluid or adnexal mass, consider a ruptured ectopic pregnancy. Proceed with an operative laparoscopy to confirm your diagnosis and stabilize the patient.

Alright, if the hCG test is negative, consider another gynecologic emergency, adnexal torsion, although keep in mind this may also occur during pregnancy. This is most commonly due to the presence of an ovarian cyst, and occurs when an enlarged adnexa, consisting of the ovary, fallopian tube, and supporting ligaments, twists upon itself and stops blood flow to the ovary and tube. The patient may report sudden onset of pelvic or abdominal pain, fever, nausea, and vomiting. Physical examination will demonstrate abdominal tenderness with rebound pain or guarding, and possibly a pelvic mass.

The ultrasound will show an enlarged adnexa, typically larger than 5 centimeters in size, and may demonstrate absent Doppler flow in the ovarian vessels, as well as the whirlpool sign that reflects the twisted arterial and venous flow representing the twisted pedicle of the adnexa. These findings are consistent with adnexal torsion. Proceed with an operative laparoscopy for diagnosis and rapid intervention in order to preserve ovarian function and fertility.

Now that we discussed the unstable patient, let’s talk about stable ones.

The first step here is to perform a focused history and physical exam, and obtain an hCG to assess for pregnancy. If hCG is positive, evaluate for causes of acute pain that are related to pregnancy.

Let’s start with ectopic pregnancy. The history usually reveals unilateral pelvic pain, and possibly vaginal bleeding. The patient may report a history suggestive of fallopian tube injury, such as prior pelvic inflammatory disease, tubal surgery, or ectopic pregnancy. Physical exam may reveal abdominal or pelvic tenderness, or an adnexal mass with tenderness.

If you see this, consider an ectopic pregnancy and obtain a quantitative hCG and a pelvic ultrasound. If the hCG is greater than 3,500 and the ultrasound demonstrates no evidence of an intrauterine pregnancy, with or without an adnexal mass, the diagnosis is ectopic pregnancy.

Here’s a high-yield fact! If the hCG is 3,500 or more, the ultrasound should reveal evidence of an intrauterine pregnancy. At that hCG level, the absence of intrauterine findings is diagnostic of an ectopic pregnancy.

However, if the hCG is less than 3,500, you might be dealing with a miscarriage or even a normal early pregnancy, so be sure to follow the patient closely with serial hCG levels and ultrasounds.

Next, consider early pregnancy loss. In this case, the patient is more likely to report midline pelvic pain and possibly cramping and vaginal bleeding. The physical exam may or may not reveal an open cervical os with bleeding and passage of tissue. Consider an early pregnancy loss and obtain a pelvic ultrasound. If it shows evidence of a nonviable intrauterine pregnancy, the diagnosis is early pregnancy loss.

Here’s a clinical pearl! A nonviable pregnancy can appear on ultrasound in a variety of ways, such as having a crown-rump length of 7 mm or greater with no cardiac activity, or a mean gestational sac diameter measuring 25 mm with no embryo.

Now that we discussed acute pelvic pain in pregnancy, let’s move on to patients with a negative hCG test, starting with primary dysmenorrhea. These patients report cyclic pelvic pain that began 6 to 12 months after menarche and may also experience cyclic nausea, vomiting, diarrhea, headaches, and muscle cramps. The physical exam might be positive for mild abdominal or pelvic tenderness, as well as a normal uterus and no adnexal masses. The cyclic nature of the symptoms and the absence of pelvic pathology is the key to the diagnosis of primary dysmenorrhea.