Pelvic inflammatory disease (PID) is a broad term that encompasses a spectrum of infection and inflammation of the upper female genital tract, resulting in a range of abnormalities.
The highest incidence is seen among sexually-active women in their teens, with 75% cases being under 25 years of age. In the United States, approximately 1 million females are thought to be afflicted with PID per year, and nearly 275,000 of them are believed to be hospitalised 7.
More common presentations include acute pelvic pain (of variable intensity), cervical motion tenderness, vaginal discharge, fever, dyspareunia, and leukocytosis. Right upper quadrant pain from perihepatitis in Fitz-Hugh-Curtis syndrome is possible.
PID is defined as an acute clinical syndrome associated with ascending spread of micro-organisms, unrelated to pregnancy or surgery. The infection generally ascends from the vagina or cervix to the endometrium (endometritis), then to the fallopian tubes (salpingitis), and then to and/or contiguous structures (tubo-ovarian abscess).
It can result from a number of causative organisms:
- less common
PID is usually bilateral, except when it is caused by the direct extension of an adjacent inflammatory process such as appendiceal, diverticular, or post-surgical abscesses.
Imaging features are often non-specific but are disproportionate to what may be apparent from symptoms. If imaged early (e.g. during the cervicitis stage), there may be no finding. If imaged very late, there may be an adnexal mass-like region with surrounding inflammatory change, and the fallopian tube and ovary may not be able to be distinguished.
Other associated findings include 7:
- soft tissue stranding and infiltration of pelvic floor fascial planes
- thickening of uterosacral ligaments
Ultrasound often only demonstrates ascitic fluid in the peritoneal cavity or non-specific thickening and increased vascularity of the endometrium 8.
In the most severe cases, ultrasound may show adnexal masses with a heterogeneous echo-pattern.
Some sonographic signs associated with tubal inflammation include:
- thickened/dilated fallopian tubes
- incomplete septa in the tube
- increased vascularity around the tube
- echogenic fluid in the tube (pyosalpinx)
- thickening of the uterosacral ligaments
- complex free fluid in the pouch of Douglas (cul-de-sac)
- pelvic fat stranding or haziness
- indistinct uterine border
- fallopian tube thickening of >5 mm with enhancing wall
- reactive lymphadenopathy
- lymph nodes in the para-aortic and paracaval regions often become prominent due to infection draining in to lymphatics along the course of the gonadal veins
May show an ill-defined adnexal mass containing fluid with various signal intensities:
- T1+C (Gd): wall and surrounding tissues may enhance
Treatment and prognosis
In the absence of complications, pelvic inflammatory disease is often treated conservatively with education, antibiotics, and partner tracing.
- tubo-ovarian abscess
- ovarian vein thrombosis
- adhesion formation with resultant bowel obstruction
- Fitz-Hugh-Curtis syndrome
fallopian tube carcinoma
- consider in a patient without risk factors for PID and/or a patient in whom a course of antibiotics did not resolve the PID
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Ultrasound - gynaecology
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- pelvic inflammatory disease
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