Tubo-ovarian Abscess

A tubo-ovarian abscess is a collection of pus involving the fallopian tube and ovary, usually the end stage of pelvic inflammatory disease.

• Organisms are polymicrobial: gonorrhoea, chlamydia, anaerobes, enteric Gram-negative bacilli and streptococci.
• Rupture causes peritonitis and sepsis and is a surgical emergency.
• Diagnosis and treatment must begin early to save fertility.

Lower abdominal pain, fever, vaginal discharge, nausea, vomiting, cervical motion tenderness and a tender adnexal mass.

• Tachycardia, peritonism, hypotension with rupture.
• Differential diagnosis: appendiceal abscess, ectopic pregnancy, ovarian torsion, endometrioma, diverticulitis, ovarian cancer, pelvic inflammatory disease without abscess.
• Complications: rupture, septic shock, peritonitis, tubal infertility, ectopic pregnancy, chronic pelvic pain and recurrent infection.

Diagnosis is clinical, confirmed by ultrasound or CT and supported by cultures.

• Pregnancy test; full blood count, C-reactive protein, blood cultures, urinalysis.
• Transvaginal and abdominal ultrasound: complex adnexal mass with thick walls, septa and internal echoes; CT scan with contrast where the diagnosis is unclear.
• Endocervical NAAT for gonorrhoea and chlamydia; high vaginal swab; HIV and syphilis tests.
• Culture of drained pus.

Give IV broad-spectrum antibiotics, drain large or unresponsive abscesses, and operate for rupture.

• Supportive: admission; IV fluids; analgesia; monitor temperature, pulse and blood pressure; remove an intrauterine device if there is no response in 48 to 72 hours.
• Pharmacological: ceftriaxone 1 g IV daily plus doxycycline 100 mg oral or IV 12-hourly plus metronidazole 500 mg IV 8-hourly. Alternative: clindamycin 900 mg IV 8-hourly plus gentamicin 5 mg/kg IV once daily (maximum 480 mg). After afebrile for 24 to 48 hours, change to doxycycline 100 mg oral 12-hourly plus metronidazole 400 mg oral 12-hourly to complete 14 days. Paracetamol 1 g IV or oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: image-guided or laparoscopic drainage for abscesses above 7 cm or for no improvement after 48 to 72 hours of antibiotics; laparotomy with drainage, salpingectomy or hysterectomy with bilateral salpingo-oophorectomy for rupture, shock or failed drainage.
• Special groups: in pregnancy give ceftriaxone 1 g IV daily plus metronidazole 500 mg IV 8-hourly plus azithromycin 500 mg IV daily, and avoid doxycycline. In HIV infection give the full regimen and review antiretroviral treatment with the HIV team. In renal impairment adjust gentamicin or use ceftriaxone.
• Red flags: shock, peritonitis, sudden worsening of pain (rupture), persistent fever after 72 hours, septic pelvic thrombophlebitis.
• Follow-up: ultrasound at 1 to 2 weeks; partner treatment; review at 4 weeks and 3 months; counsel on fertility.