Clinical History
A pre-menarche previously healthy 12 year-old girl presented with pain, nausea and vomiting. Pain was initially referred to the left flank, with positive Murphy sign, and several hours later to the left pelvic region with progressive signs of peritoneal irritation. Laboratory data was unremarkable.
Imaging Findings
Abdominal/renal US: hypoperfusion of the lower pole of a morphologic normal left kidney on color Doppler (CDS) was seen (fig.1). Additionally, a left adnexial fusiform dilated structure with incomplete septations related to distended fallopian tube and minimal Douglas pouch free fluid were present (fig.2). There were no other abdominal or pelvic abnormalities.
Pelvic US (fig.3, 4) several hours later: increased dilatation of the left fallopian tube, apparently twisted towards itself and with a thickened wall, and moderated amount of free fluid was noted. The left ovary was only slightly enlarged. On CDS adnexial vascularization was preserved. Left kidney abnormalities remained stable.
The initial suspicion of acute pyelonephritis was set apart, and an acute pelvic disorder was the main concern. Despite a relatively normal ovary, isolated adnexial torsion was suggested and due to progressive clinical worsening she was submitted to urgent surgery. The diagnosis of isolated fallopian tube torsion was confirmed intraoperatively (fig.5).
Discussion
Fallopian tube torsion most often occurs in association with ovarian torsion. Isolated fallopian tube torsion is an exceedingly rare entity occurring in 1:1.5 million female. Usually affects adolescents and young women, and it’s rarely seen in post-menopause. Risk factors for isolated fallopian tube torsion include both intrinsic and extrinsic factors, such as long or congested mesosalpinx, tubal hipermotility, pelvic inflammatory disease, tubal ligation, tubal or non-tubal gynecological neoplasms, pelvic adhesions, and trauma [1-4].
Right fallopian tube torsion is more common, presumably due to a relative fixation of the left tube in the hemipelvis by the sigmoid colon and mesentery [2].
A sequential mechanism of action has been proposed invoking mechanical obstruction of adnexal veins and lymphatics, leading to pelvic congestion and edema, enlargement of the fimbrial end, and subsequent partial to complete torsion of the involved tube.
Presenting symptoms include acute onset of pelvic pain, either crampy or constant and dull. Pain may radiate to the groin or thigh and may be accompanied by nausea, vomiting, and peritoneal signs. Laboratory tests may show normal or slightly elevated inflammatory parameters [2].
US is the initial imaging modality in acute pelvic pain [5]. In torsion, the fallopian tube is dilated, may have thickened echogenic walls and internal debris, and twisted configuration with tapered ends (as the CT “beak sign”) [2]. As with other tubal diseases, identification of a normal ovary is helpful for confirming the tubal origin of a cystic mass [1]. Similar to ovarian torsion, Doppler findings can be misleading due to the dual arterial supply of the fallopian tubes and the ovaries [4]. Secondary signs include intraperitoneal free fluid, peritubular fat hyperechogenicity and regional ileus [1].
On an emergency setting, CT may be helpful for excluding other pathologies (particularly to exclude appendicitis if right sided) when the diagnosis cannot be made with US.
Although rare, it is important to recognize this entity in the presence of hydrosalpinx with a sonographically normal ovary in a patient with acute pain, as a delayed diagnosis and treatment may result in increased morbidity [1].
In our case, the initial presentation and Doppler abnormalities on the left kidney gave rise to some diagnostic confusion. At follow-up DDS, kidney vascularization improved (fig.6) and we thought it to be related with venous compromise from the left ovarian vein congestion. To our knowledge, this association hasn’t been described in the literature.
Differential Diagnosis List
Isolated tubal torsion
ovarian torsion
rupture of the ovarian follicle or cyst
ectopic pregnancy
inflammatory pelvic disease