Tubo-Ovarian Abscess
A tubo-ovarian abscess is a walled-off collection of pus involving the fallopian tube and ovary, usually developing as a complication of pelvic inflammatory disease. Infection ascending from the cervix inflames the tube, and as the inflammation progresses the tube and ovary become matted together into a single inflammatory mass containing pus. It is a serious condition: untreated, it can rupture and cause life-threatening infection throughout the abdomen, and even when treated successfully it commonly leaves scarring that affects fertility. Most cases respond to intravenous antibiotics, often combined with image-guided drainage, and surgery is needed less often than it once was.
What is it?
The upper female genital tract—the uterine cavity, fallopian tubes, and ovaries—is normally free of bacteria, protected by the cervix and its mucus. Pelvic inflammatory disease occurs when organisms ascend past this barrier and infect these structures.
A tubo-ovarian abscess is the most serious local complication of that process. As infection inflames the fallopian tube, the tube becomes swollen and its open end may seal shut, trapping infected material inside. Pus accumulates, the inflamed tube adheres to the adjacent ovary, and surrounding structures including bowel and omentum become stuck to the mass as the body attempts to wall off the infection. The result is a single inflammatory complex in which the tube and ovary can no longer be distinguished from one another.
Understanding this sequence explains several features of the condition. It explains why the abscess is typically an ill-defined complex mass rather than a simple cavity. It explains why the ovary is involved even though infection began in the tube. And it explains why scarring and adhesions are such common long-term consequences—the walling-off process that contains the infection also permanently distorts the anatomy.
The organisms involved are usually multiple. Chlamydia trachomatis and Neisseria gonorrhoeae are the classic initiating organisms in sexually transmitted pelvic inflammatory disease, but by the time an abscess has formed, the contents typically also contain bacteria from the vaginal and bowel flora, particularly anaerobes such as Bacteroides and Peptostreptococcus, along with E. coli and streptococci. This polymicrobial character is why treatment requires broad-spectrum antibiotics with reliable anaerobic cover rather than treatment directed only at chlamydia or gonorrhoea. Notably, cultures taken from abscesses frequently grow no chlamydia or gonorrhoea at all, even when those organisms initiated the process, because the later bacteria have overtaken them.
Most cases follow ascending sexually transmitted infection, and risk factors reflect this: multiple sexual partners, a new partner, inconsistent barrier contraception, younger age, and a previous episode of pelvic inflammatory disease, which substantially increases the risk of another.
Intrauterine devices deserve a specific and accurate comment, because the association is frequently overstated. Risk of pelvic infection is increased in the first few weeks after insertion, reflecting the introduction of organisms at the time of the procedure. Beyond that early window, an intrauterine device does not meaningfully increase the risk of pelvic inflammatory disease. Women with a device who develop symptoms should be assessed, but having one is not in itself a reason to avoid this method of contraception.
A minority of abscesses arise without sexually transmitted infection. Appendicitis, diverticulitis, inflammatory bowel disease, and previous pelvic or abdominal surgery can all lead to abscess formation involving the adnexa. Recent uterine instrumentation, including termination of pregnancy, endometrial sampling, and hysteroscopy, carries a small risk.
Abscesses in postmenopausal women warrant particular caution. They are uncommon in this group, and when they occur, an underlying malignancy—of the ovary, tube, uterus, or bowel—is present in a meaningful proportion. Investigation for cancer is therefore appropriate rather than assuming a purely infective process, and this is an important exception to the usual approach.
Actinomyces infection is an uncommon cause, associated with prolonged intrauterine device use, and characteristically produces a dense, infiltrating inflammatory mass that can closely mimic cancer on imaging.
The presentation develops over days rather than hours in most cases.
Lower abdominal and pelvic pain is the dominant symptom, usually affecting both sides but sometimes predominantly one. It is typically constant, worsening, and severe enough to limit normal activity.
Fever and chills are common but not universal, and a normal temperature does not exclude the diagnosis—a point worth knowing, since absence of fever sometimes leads to the condition being considered less likely than it is.
Abnormal vaginal discharge, often purulent, is frequent. Abnormal bleeding—between periods, heavier periods, or bleeding after intercourse—occurs in many women. Deep pain during intercourse is characteristic of pelvic inflammatory disease generally.
Nausea, vomiting, and urinary symptoms are common and can direct attention toward gastrointestinal or urinary causes.
On examination there is marked lower abdominal tenderness, often with guarding, and pelvic examination reveals significant tenderness on moving the cervix and on palpating the adnexa, with a mass sometimes palpable.
Right upper abdominal pain can occur in a minority, reflecting inflammation of the liver capsule and surrounding tissue—a phenomenon known as Fitz-Hugh-Curtis syndrome. It can be prominent enough that the presentation is mistaken for gallbladder disease.
Rupture is the most feared complication and is a surgical emergency. It presents with sudden worsening and generalisation of pain, a rigid abdomen, high fever with rigors, rapid heart rate, falling blood pressure, and confusion. This is peritonitis with sepsis, and it carries significant mortality without prompt treatment.
Diagnosis combines clinical assessment, imaging, and laboratory testing.
Transvaginal ultrasound is the first-line test and is often sufficient. Characteristic findings include a complex adnexal mass with thick irregular walls, multiple internal compartments, low-level internal echoes representing pus and debris, fluid-debris levels, free fluid in the pelvis, marked increase in blood flow within the inflamed walls, and loss of the normal distinction between tube and ovary. A dilated fluid-filled tube with incomplete internal folds, sometimes described as a cogwheel appearance, is characteristic of tubal involvement.
CT of the abdomen and pelvis with contrast is widely used, particularly where the diagnosis is uncertain or an abdominal source is possible. It defines the size and extent of the collection, identifies appendicitis, diverticulitis, or other sources, detects free gas or fluid suggesting rupture, and provides the road map for drainage.
MRI offers excellent soft tissue characterisation and is preferred in pregnancy and in younger women where radiation is a concern.
Blood tests typically show a raised white cell count and elevated inflammatory markers, though normal results do not exclude the diagnosis.
Testing for chlamydia and gonorrhoea is essential, alongside broader sexually transmitted infection screening including HIV and syphilis. Cultures from any drained material guide antibiotic choice.
A pregnancy test is mandatory in every case, since ectopic pregnancy is a critical alternative diagnosis with an entirely different management pathway.
The differential includes ectopic pregnancy, ovarian torsion, ruptured ovarian cyst, appendicitis, diverticulitis, endometriosis with an endometrioma, and ovarian cancer—which can closely resemble an abscess on imaging, particularly in older women.
Important to Know
Tubo-ovarian abscess requires prompt hospital treatment, and the great majority of women respond well. Care is coordinated by gynaecologists, with interventional radiology, infectious disease, and sexual health services involved.
Intravenous broad-spectrum antibiotics are the foundation of treatment, chosen to cover gram-negative organisms, streptococci, and anaerobes, which is essential given the polymicrobial nature of these infections. A substantial majority of abscesses—commonly reported at around 70 percent or more—resolve with antibiotics alone. Treatment typically continues intravenously until there is clear clinical improvement, followed by an extended oral course.
Image-guided drainage has changed management considerably and is now used earlier rather than as a last resort. An interventional radiologist places a needle or catheter into the collection under ultrasound or CT guidance, accessing it through the abdominal wall, the vagina, or the rectum depending on position. It is minimally invasive, can usually be performed under sedation, and substantially improves resolution rates while shortening hospital stay. It is generally considered for larger abscesses—thresholds around 7 centimetres are commonly cited—and for women not improving within 48 to 72 hours of antibiotics.
Surgery is now needed less often than historically. It is indicated for rupture or suspected rupture, for failure of antibiotics and drainage, for haemodynamic instability, and where the diagnosis is uncertain and malignancy is a possibility. Laparoscopy is preferred where feasible. Fertility-preserving surgery—draining and washing out rather than removing tube and ovary—is the aim in women of reproductive age, though extensive disease sometimes makes removal necessary.
An intrauterine device present at the time of diagnosis is generally removed once antibiotics have been started, allowing the antibiotic to take effect first.
Partner notification and treatment are essential and are not optional. Untreated partners lead to reinfection, and repeated episodes compound tubal damage. Sexual health services provide this and can manage notification confidentially where that is a concern.
The long-term consequences of tubo-ovarian abscess are substantial and deserve honest discussion rather than being left unmentioned.
Fertility is commonly affected. The scarring and adhesions that form as the body walls off infection distort or block the fallopian tubes, and tubal factor infertility is a recognised consequence. The risk rises with each episode of pelvic inflammatory disease, and having had an abscess specifically carries a higher risk than uncomplicated infection. Women who have had an abscess and later have difficulty conceiving should be assessed early rather than waiting the usual interval, and in vitro fertilisation bypasses damaged tubes effectively where they are blocked.
Ectopic pregnancy risk is increased several-fold, because a partially damaged tube may allow sperm through but not permit the fertilised egg to travel back to the uterus. Any woman with a history of pelvic infection who has a positive pregnancy test with pain or bleeding needs early assessment to establish where the pregnancy is located.
Chronic pelvic pain affects a significant proportion, arising from adhesions and from the changes that persistent inflammation produces in pain processing. This is a real and often under-recognised consequence, and it deserves active management rather than dismissal.
Recurrence is possible, particularly with reinfection.
Prevention is achievable and is worth emphasising. Consistent condom use prevents the sexually transmitted infections that cause most cases. Screening for chlamydia in younger sexually active women identifies and treats infection before it ascends, and has been shown to reduce rates of pelvic inflammatory disease. Prompt treatment of any diagnosed pelvic infection, completing the full antibiotic course, and ensuring partners are treated all prevent progression to abscess.
A broader point about pelvic inflammatory disease is relevant here. Because its symptoms can be mild, it is frequently untreated or treated late, and the damage accumulates silently. A low threshold for testing and treating suspected pelvic infection is deliberate clinical policy, since the consequences of missing it are considerably worse than the cost of treating empirically.
Care is coordinated by gynaecology with interventional radiology, sexual health, and fertility services as needed. Imaging, laboratory results, and clinical findings are interpreted together, with particular attention in postmenopausal women to the possibility of underlying malignancy.
Patient education plays an important role. Understanding that this is a complication of infection rather than a failure of hygiene, that most cases resolve without surgery, that partner treatment prevents recurrence, that fertility may be affected and warrants early assessment if conception proves difficult, and which symptoms signal rupture all contribute to appropriate care.
Red flag symptoms include sudden worsening or spreading of abdominal pain; a rigid, board-like, or exquisitely tender abdomen; high fever with shaking chills; rapid heart rate, low blood pressure, dizziness, or fainting; confusion or drowsiness; persistent vomiting with inability to keep down fluids; and failure to improve after 48 to 72 hours of treatment. These indicate possible rupture and sepsis and require immediate emergency assessment. Any woman with pelvic pain and a positive pregnancy test requires urgent evaluation to exclude ectopic pregnancy.