15 Oct 2026 · Case #040
Ovarian torsion
This page works the case through in full, answer included. If you would rather reason it out yourself: Play this case
Diagnosis
Ovarian torsion
First-line treatment
Urgent laparoscopic detorsion
How the diagnosis is reached
Sudden, severe, one-sided pelvic pain with vomiting and an adnexal mass is ovarian torsion until proven otherwise, and the first job is to remove the diagnosis that kills fastest: a negative pregnancy test takes ectopic off the table. The rest of the immediate differential falls away on the same page, since an entirely clean dipstick argues against renal colic and urinary infection, and the absence of cervical motion tenderness argues against pelvic inflammatory disease. What sets this up is the cyst. An ovary carrying a lesion above about 5 cm has a lead point, enough weight to let it twist on its pedicle, and torsion in a completely normal ovary is uncommon in adults. The ultrasound findings follow directly from the mechanics: venous and lymphatic drainage is choked off before arterial inflow, so the ovary becomes engorged and oedematous, swelling from a normal 3 cm to 8 cm, and the expanding stroma shoves the follicles out to the rim. The whirlpool sign of the coiled pedicle is the most specific finding of all. The trap worth remembering is the Doppler: the ovary has a dual blood supply from both the ovarian and uterine arteries, and torsion is often intermittent, so flow is frequently still present. Preserved Doppler flow does not exclude torsion, and a reassuring scan must never delay theatre when the clinical picture reads like this one. Theatre is where this is both confirmed and treated: the ovary is untwisted laparoscopically and kept. The instinct to remove a dusky, blue-black ovary should be resisted, because colour on the table predicts later function very poorly and the great majority recover once perfusion returns; oophorectomy is for an ovary that is frankly necrotic, or for postmenopausal women. The 6 cm cyst that started this comes out at the same operation or at an interval, so it cannot do it again, and ovariopexy is considered where torsion recurs. Time is the variable that really matters, since prolonged ischaemia, not the twist itself, is what turns a salvageable ovary into a lost one.
Key clinical clues
- Sudden severe unilateral pelvic pain with vomiting and a restless, unsettled patient
- A known 6 cm ovarian cyst providing the lead point for the ovary to twist on
- A negative pregnancy test, removing ectopic pregnancy from the differential
- An enlarged oedematous ovary with its follicles displaced to the periphery
- A whirlpool sign in the twisted pedicle, remembering that preserved flow would not exclude it
The case in full
Presenting complaint
Patient history
A 26-year-old woman has had sudden, severe right-sided pelvic pain for five hours. It began abruptly while she was at the gym, has come in waves since, and she has vomited several times.
Background
Patient history
Her last period was two weeks ago and her cycle has always been regular. She uses condoms for contraception. An ultrasound last year showed a 6 cm cyst on the right ovary that was being monitored.
Examination and observations
Physical examination
She is restless and cannot find a comfortable position. There is marked right iliac fossa tenderness with guarding, and a tender mass is felt on bimanual examination. There is no cervical motion tenderness.
| Parameter | Value | Reference |
|---|---|---|
| Temperature | 37.4 °CRef 36.1–37.5 | 36.1–37.5 |
| Heart rate | 104 bpmRef 60–100 | 60–100 |
| Blood pressure | 118/70 mmHg | – |
| Respiratory rate | 18 /minRef 12–20 | 12–20 |
Bedside tests and bloods
Laboratory results
A pregnancy test and bloods are sent.
| Parameter | Value | Reference |
|---|---|---|
| Urine hCG | NegativeRef Negative | Negative |
| White cell count | 12.8 ×10⁹/LRef 4.0–11.0 | 4.0–11.0 |
| CRP | 22 mg/LRef <5 | <5 |
| Haemoglobin | 132 g/LRef 115–165 | 115–165 |
| Lactate | 1.6 mmol/LRef <2.0 | <2.0 |
| Urine dipstick | No blood, nitrites or leucocytesRef Negative | Negative |
Pelvic ultrasound
Imaging
Transvaginal ultrasound shows an enlarged, oedematous right ovary of 8 cm displaced towards the midline, with its follicles pushed out to the periphery. The known 6 cm cyst is still present, with a small volume of free fluid.
Doppler and progress
Imaging
Colour Doppler shows a twisted vascular pedicle with a whirlpool appearance and reduced arterial flow on the right. The left ovary and both tubes look normal. She continues to vomit and the pain has not settled with morphine.