Investigations
1st investigations to order
pregnancy test
Test
If positive, critical alternatives such as ectopic pregnancy should be considered.
Regardless of result, torsion must still be considered, as torsion can occur in pregnancy.
Result
negative or positive
urinalysis
Test
If positive for red blood cells, white blood cells, or nitrates, an alternative diagnosis, such as renal colic or urinary tract infection, should be considered.
Result
negative
FBC
group and save
Test
Order a group and save sample in case the patient needs surgery.
Result
blood group
sickle cell test
Test
Order a sickle cell test in case the patient needs surgery.
Result
presence or absence of sickle cell trait
C-reactive protein (CRP)
transvaginal ultrasound
Test
Request an urgent ultrasound scan for any patient with suspected ovarian torsion.[2][40][39]
Findings depend on duration of symptoms; degree of torsion and whether torsion is intermittent or chronic; whether a mass is present; or whether the fallopian tube is twisted along with the ovary.
Thickening of the fallopian tube may be noted as a fusiform or tubular structure.[39][43] Ovary may be enlarged, with prominent heterogeneous central stroma and small peripheral follicles.
Rarely, the fallopian tube alone may be twisted (without the ovary).
Not considered appropriate in children or in women who have not been sexually active; abdominal or transrectal ultrasound is recommended (see below).[25]
Result
enlarged ovary; solid, cystic, or complex adnexal mass, which is typically tender on pressure with the ultrasound probe; the whirlpool sign (which appears as twisting of the thickened vascular pedicle of the enlarged ovary) and free fluid in the pelvis
abdominal or transrectal ultrasound
Test
Appropriate for children with suspicion of ovarian torsion or other patients where transvaginal ultrasound (TVUS) is inappropriate, including those who have not been sexually active or who have vaginal stenosis; use whichever gives the best view.
Full bladder needed for abdominal scan, which may be challenging in children in an emergency situation.
Result
solid, cystic, or complex adnexal mass
Doppler flow
Test
May be used to assess blood flow to the ovary. However, loss of arterial perfusion is a late event in ovarian torsion. A degree of venous outflow restriction is more common.
One review found that evaluating ovarian vascular flow using Doppler slightly improved the diagnostic accuracy of ultrasound but this was not statistically significant.[40]
Result
Normal or abnormal Doppler signals in ovarian vessels
PCR, nucleic acid amplification test, or cervical culture
Test
If positive for Neisseria gonorrhoeae and/or Chlamydia trachomatis, an alternative diagnosis such as pelvic inflammatory disease should be considered. British Association for Sexual Health & HIV: PID guidelines 2019 Opens in new window
Result
negative
surgical visualisation
Test
Direct visualisation of torsion is the definitive diagnostic tool, with high clinical suspicion of torsion.[1] Also allows for treatment.
Result
confirms diagnosis
Investigations to consider
CT abdomen/pelvis
Test
Order if expert ultrasound is not immediately available or if the results are inconclusive. However, CT has less diagnostic value than transvaginal ultrasound, increasing time and cost of evaluation.[32][40]
Avoid in pregnancy if possible.
Result
may show fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, low-volume ascites, and uterine deviation towards the twisted side
MRI abdomen/pelvis
Test
Order if ultrasound is inconclusive. However, MRI has less diagnostic value than transvaginal ultrasound, increasing time and cost of evaluation.[32][40]
Result
may show fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, low-volume ascites, and uterine deviation towards the twisted side
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