Acute pelvic pain in the reproductive age group (including suspected PID and tubo-ovarian abscess)
ACR AC Acute Pelvic Pain in the Reproductive Age Group (2023 rev)The general entry point for acute pelvic pain in a premenopausal woman. Transabdominal plus transvaginal ultrasound with Doppler is the initial study for almost every version of this question; contrast-enhanced CT earns its place when the differential is genuinely broad or a tubo-ovarian abscess needs mapping for drainage.
Premenopausal woman with acute lower abdominal or pelvic pain, with or without fever, discharge and raised inflammatory markers. The differential spans gynaecological, obstetric, urinary and gastrointestinal causes.
Referenced decision support — confirm against your local protocol.
Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.
Accept as requested
Pelvic ultrasound — transabdominal and transvaginal
Ultrasound pelvis (transabdominal ± transvaginal)
What we'd amend, and why
- Combined transabdominal and transvaginal ultrasound with Doppler is the initial study when a gynaecological cause is plausible: it shows the adnexa at a resolution CT cannot approach, demonstrates a dilated tube, an abscess or a haemorrhagic cyst, and does it without radiation in a group who are young and often pregnant or trying to be. Doppler assessment of both ovaries is part of the examination, not an extra.
Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.
How was this decided?
- pathwayany — Premenopausal women
Decision support only. Local protocol takes precedence.
Worth asking the referrer (1)
None of these hold the request up. They sharpen the protocol or the plan that follows.
- What is the pregnancy test result?A positive test redirects the question to the ectopic pathway, where the urgency and the reporting emphasis are different.
Pathways
Big forks are separate pathways; the first whose conditions match is the one used.
Febrile or septic — suspected tubo-ovarian abscess
| Role | Study & protocol | Why this answers the question |
|---|---|---|
| First line | Ultrasound pelvis (transabdominal ± transvaginal) Pelvic ultrasound — transabdominal and transvaginal usually appropriate | Fever raises the tempo rather than changing the study. Transabdominal and transvaginal ultrasound with Doppler still leads, because it is the test that resolves a pyosalpinx, a tubo-ovarian abscess and a torted ovary in the adnexa, and because pelvic inflammatory disease is treated on clinical suspicion — the scan is looking for the complication, not for permission to give antibiotics. What the fever changes is that this is a same-attendance scan rather than a slot, and that both ovaries need a specific Doppler look, since torsion can be masked by an inflammatory picture. |
| Second line | CT Abdomen and Pelvis CT Abdomen and Pelvis — Portal Venous Phase | In a septic woman the contrast-enhanced CT follows on the same attendance rather than the next available list, and it has two specific jobs: to explain a sepsis the ultrasound has not accounted for — appendicitis, diverticulitis, a urinary source — and to map a known tubo-ovarian abscess against bowel and vessels for the interventional radiologist. Portal-venous enhancement is what separates the thick enhancing abscess wall from adjacent unopacified bowel, so an unenhanced study is not a substitute for this question. |
| Problem solving | MRI Pelvis (Gynaecological) MRI Pelvis — general gynaecological | Where ultrasound is equivocal and radiation is best avoided — a young or pregnant patient — MRI separates a tubo-ovarian abscess from an endometrioma, a degenerating fibroid or a malignant mass better than CT does. It is the slower route, so in a septic patient it is chosen deliberately rather than by default. |
- A complex adnexal mass is not a tubo-ovarian abscess by virtue of the fever alone, and an afebrile woman with normal markers is the group in whom that label is most often wrong — the fact cuts both ways and is worth stating on the report.
- If drainage is being considered, say so on the request: the relationship of the collection to bowel and vessels is a different reporting job from confirming that it exists.
Premenopausal women
Matches your inputsDefault| Role | Study & protocol | Why this answers the question |
|---|---|---|
| First line | Ultrasound pelvis (transabdominal ± transvaginal) Pelvic ultrasound — transabdominal and transvaginal usually appropriate | Combined transabdominal and transvaginal ultrasound with Doppler is the initial study when a gynaecological cause is plausible: it shows the adnexa at a resolution CT cannot approach, demonstrates a dilated tube, an abscess or a haemorrhagic cyst, and does it without radiation in a group who are young and often pregnant or trying to be. Doppler assessment of both ovaries is part of the examination, not an extra. |
| Second line | CT Abdomen and Pelvis CT Abdomen and Pelvis — Portal Venous Phase | Contrast-enhanced CT takes over when the differential is broad enough that appendicitis, diverticulitis or a urinary cause is as likely as a gynaecological one, when ultrasound is non-diagnostic in a septic patient, or when a known tubo-ovarian abscess needs mapping before drainage. Portal-venous enhancement is what separates the thick enhancing abscess wall from adjacent unopacified bowel. |
| Problem solving | MRI Pelvis (Gynaecological) MRI Pelvis — general gynaecological | Where ultrasound is equivocal and radiation is best avoided — a young or pregnant patient — MRI separates a tubo-ovarian abscess from an endometrioma, a degenerating fibroid or a malignant mass better than CT, on the strength of its soft-tissue contrast. |
Pitfalls
- Accepting a CT request for a young woman when the clinical story is gynaecological — it gives a lower yield for adnexal pathology and an avoidable gonadal dose.
- Reporting a normal pelvis without commenting on the appendix; right-sided pelvic pain in this group is appendicitis until the appendix is accounted for.
- Calling a complex adnexal mass a tubo-ovarian abscess in an afebrile woman with normal markers — an endometrioma, a haemorrhagic cyst and a malignancy all look like that.
- Forgetting that torsion can coexist with, and be masked by, an inflammatory picture; the ovaries need a specific look, not a passing mention.
- Sending a woman back for the ultrasound she has already had. Where the scan is done and non-diagnostic, the next study is the CT — repeating the failed step is a false correction, and it costs a septic patient the hours the CT would have saved.
Priors — what to pull first
- Compare with any recent pelvic ultrasound: a cyst that was there three months ago and is unchanged is unlikely to be the cause of today’s pain.
- A previous positive chlamydia or gonorrhoea result, or a recent instrumentation of the uterus, materially raises the likelihood of PID.
What makes a good request
- The pregnancy test result is the single most useful line on the request: it separates the ectopic pathway from everything else.
- Pelvic inflammatory disease is a clinical diagnosis treated on suspicion. Imaging is for complications — pyosalpinx, tubo-ovarian abscess — and for the alternative diagnoses, not for permission to treat.
- A tubo-ovarian abscess that is being considered for drainage needs its relationship to bowel and vessels defined, which is a different reporting job from confirming it exists.
- Say on the request when the ultrasound has already been done and was non-diagnostic. That single line moves the patient a rung along the pathway, and without it a CT request for a septic woman whose scan has already failed comes back "do the ultrasound first" — a correction the referrer is right to ignore, and the fastest way to train a department out of reading vetting advice.
Scoring this once it is done
The classification and risk tools this question ends in.
How these studies are acquired
Contrast, phases and timing for every study on the pathways above.
Confirm locally
- Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
- Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.
References
- ACR Appropriateness Criteria — Acute Pelvic Pain in the Reproductive Age Group: 2023 Update · ACR Appropriateness Criteria
- ACR Appropriateness Criteria — Postmenopausal Acute Pelvic Pain · ACR Appropriateness Criteria
- Cross-sectional imaging of pelvic inflammatory disease: diagnostic pearls and pitfalls on CT and MR · Primary literature
Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.