What is the most common cause of a tubo-ovarian abscess?

From the Guidelines

The most common cause of a tubo-ovarian abscess is pelvic inflammatory disease (PID), which is typically caused by an ascending polymicrobial infection from the lower genital tract, often involving sexually transmitted pathogens such as Neisseria gonorrhoeae or Chlamydia trachomatis, as well as normal vaginal and intestinal flora. This infection can lead to the formation of a tubo-ovarian abscess, which is a serious complication of PID. According to the 2017 guidelines for the management of intra-abdominal infections 1, PID is an infection of the upper part of the female reproductive genital tract, including the uterus, fallopian tubes, and adjacent pelvic structures, and may spread to the abdomen causing peritonitis.

The causes of PID and subsequent tubo-ovarian abscess formation are multifactorial, and include:

• Sexually transmitted organisms, such as Neisseria gonorrhoeae and Chlamydia trachomatis 1
• Microorganisms that comprise the vaginal flora, such as anaerobes, G. vaginalis, Haemophilus influenzae, enteric Gram-negative rods, and Streptococcus agalactiae 1
• Genital tract mycoplasmas, most importantly Mycoplasma genitalium 1
• Other factors, such as multiple sexual partners, history of PID, intrauterine device use, and recent gynecological procedures, which can increase the risk of developing PID and tubo-ovarian abscess.

Treatment of tubo-ovarian abscess typically involves broad-spectrum antibiotics, and may require surgical drainage or intervention in cases where antibiotic therapy is not sufficient 1. Prompt treatment is essential to prevent complications such as infertility, chronic pelvic pain, and ectopic pregnancy.

From the Research

Possible Causes of Tubo-Ovarian Abscess

• The most common cause of a tubo-ovarian abscess (TOA) is associated with pelvic inflammatory disease (PID) 2, 3, 4, 5, 6.
• PID is often caused by sexually transmitted diseases, such as Chlamydia trachomatis and Neisseria gonorrhoeae 4, 6.
• However, TOA can also occur in non-sexually active females, often due to anaerobic gut flora 5.
• Other risk factors for TOA include:
  • Intrauterine devices 2
  • Uterine procedures 2
  • Multiple sexual partners 2
  • Diabetes mellitus 2
  • Immunocompromised states 2
• Gastrointestinal sources can also be associated with TOA, particularly in cases where bowel compromise or perforation is suspected 3.

Microbial Causes

• The microbial causes of TOA are often polymicrobial, involving a combination of aerobic and anaerobic bacteria 4, 6.
• Common pathogens isolated from TOA include:
  • Escherichia Coli 3
  • Chlamydia trachomatis 4, 6
  • Neisseria gonorrhoeae 4, 6
  • Anaerobic gut flora 5