Pyosalpinx is a condition in which the fallopian tube is filled with pus secondary to acute or chronic inflammation. It leads to constitutional symptoms like fever with chills as well as acute or recurrent lower quadrant pelvic pain which can mimic appendicitis if located on the right side.
Pyosalpinx is a gynecological condition in which the fallopian tube becomes distended with pus following acute or chronic inflammation or pelvic inflammatory disease. Although the commonest cause of a pyosalpinx is sexually transmitted infection with N. gonorrhea or C. trachomatis, it can also be caused by enteric bacteria   and mycobacterium tuberculosis . Besides sexual intercourse, it can follow abortions, childbirth, pelvic surgeries, placement of intrauterine contraceptive devices, and intra-abdominal infections . Pre-pubertal girls with congenital genitourinary malformations  and Hirschsprung disease  have been reported to develop pyosalpinx without a prior history of sexual activity.
The patients are usually in the reproductive age group and present in acute cases with lower abdominal pain, fever, nausea, and vomiting. Occasionally, patients present with symptoms of acute abdomen due to rupture of the pyosalpinx with paralytic ileus, bowel obstruction or peritonitis . Acute appendicitis secondary to a gangrenous pyosalpinx has also been reported   and can present a diagnostic dilemma. Chronic cases may present with recurrent lower abdominal pain, low-grade fever, malaise, non-specific urinary symptoms, secondary infertility or ectopic pregnancies .
Based on the clinical presentation, the workup in patients with pyosalpinx must be rapid in the emergency room and gradual in chronic cases. But in all patients, the workup begins with a detailed history and physical examination. Menstrual and sexual history are vital to detect the etiology while physical examination will reveal a tender adnexal mass in a febrile patient. A wet mount preparation for trichomoniasis   and cervical cultures for gonorrhea and chlamydia must be obtained during the pelvic examination.
A pregnancy test is mandatory in all patients to rule out pregnancy, especially as ectopic pregnancy can mimic the presentation of a pyosalpinx. A complete blood count will reveal leukocytosis with elevated erythrocyte sedimentation rate and C-reactive protein levels. Other tests ordered include urinalysis, serology for syphilis, human immunodeficiency virus (HIV) and hepatitis B.
The radiological mainstay of the workup is ultrasonography. Findings include distended fallopian tubes with >5mm thickness, multiple ovarian cysts, endometrial borders which are indistinct and free fluid in the pelvis especially in acute cases . On transvaginal ultrasonography, a pyosalpinx can be differentiated from a hydrosalpinx due to its higher protein content giving rise to low echo levels  . On magnetic resonance imaging (MRI), an hydrosalpinx and a pyosalpinx can appear identical   although the pyosalpinx tends to have thickened walls  with hyperenhancement surrounded by inflammation.
The gold standard for diagnosis of a pyosalpinx is laparoscopy as it is more specific and sensitive than the clinical criteria and is a means to drain the pus for microbiological assessment and culture.