Pyosalpinx is a fallopian tube that has become filled with pus, typically as a complication of a pelvic infection that has spread upward from the lower genital tract. It represents a more advanced stage of pelvic inflammatory disease (PID), where the infection has reached and obstructed the fallopian tube, trapping infected material inside. While treatable, pyosalpinx can cause significant pain and, if not addressed, may lead to lasting damage that affects fertility.
How Pyosalpinx Develops
The process starts with an infection in the lower genital tract, most commonly from sexually transmitted bacteria like chlamydia or gonorrhea. When left untreated, these bacteria travel upward through the cervix and uterus into the fallopian tubes, causing inflammation known as salpingitis. As the infection worsens, the tube walls swell and the fimbriated end (the open, finger-like end near the ovary) can seal shut, trapping pus inside.
Other bacteria can also be involved, including organisms that normally live in the vagina and gut. Anaerobic bacteria are particularly damaging, as they can directly destroy the inner lining and tissue of the fallopian tube. In many cases, multiple types of bacteria are present at once rather than a single culprit.
Several situations raise the risk of a mixed bacterial infection reaching the tubes: infections following a miscarriage or abortion, postpartum uterine infections, and certain procedures involving the uterus. IUD use was once considered a significant risk factor, but a large study of nearly 58,000 women who received IUDs found the overall risk of developing PID was only about 0.5%, regardless of whether women were screened for sexually transmitted infections before insertion.
What Pyosalpinx Feels Like
The symptoms overlap heavily with PID, since pyosalpinx is an extension of that same infection. The most common complaint is pain in the lower belly and pelvis, which can range from a dull ache to sharp, intense pain. You may also notice unusual vaginal discharge that smells foul, bleeding between periods, pain during sex, and a burning sensation when urinating. Fever and chills are common, particularly as the infection becomes more severe.
Severe cases can cause nausea, vomiting, and a high fever above 101°F (38.3°C). A pyosalpinx can also rupture, spilling infected material into the pelvic cavity, which is a medical emergency requiring immediate treatment.
How It’s Diagnosed
Pyosalpinx is usually identified through imaging, most often an ultrasound. On ultrasound, it appears as a dilated, tube-shaped structure with noticeably thickened walls and debris floating inside the fluid. Sometimes a visible line separates the pus from clearer fluid above it, similar to how sediment settles in a jar.
CT scans show a similar picture: a serpentine or tubular structure with thick, contrast-enhancing walls and cloudy internal fluid. MRI can be especially useful for ruling out other conditions. For example, a tube filled with blood (from endometriosis or ectopic pregnancy) looks different on MRI because blood products create distinct signal patterns that pus does not.
If the pus eventually gets reabsorbed by the body on its own, the tube can remain dilated but filled with clear, watery fluid instead. This is called hydrosalpinx, and it has a distinctive “cogwheel” appearance on imaging, with thickened folds visible in cross-section but thin, non-inflamed walls. Hydrosalpinx is essentially the aftermath of a resolved pyosalpinx, but the tube is still blocked and non-functional.
Treatment Options
The first line of treatment is antibiotics, typically a combination that covers a broad range of bacteria including sexually transmitted organisms and anaerobes. Since multiple types of bacteria are usually involved, a single antibiotic is rarely sufficient. Mild to moderate cases can sometimes be managed with oral antibiotics on an outpatient basis, while more severe infections require hospitalization and intravenous antibiotics.
If antibiotics alone don’t resolve the infection, or if the tube has become severely damaged, surgical intervention becomes necessary. The options depend on how much damage has occurred. When the tube is only mildly affected, a procedure called salpingostomy can open the blocked end and allow it to drain while preserving the tube. In cases of severe destruction, the tube may need to be partially or completely removed (salpingectomy). If both tubes are severely damaged, removal of both may be recommended.
Drainage of the abscess through a needle guided by ultrasound or CT is another option in some cases, particularly when a large collection of pus needs to be evacuated before antibiotics can work effectively.
Impact on Fertility
The biggest long-term concern with pyosalpinx is damage to the fallopian tubes. Even after the infection clears, the inner lining of the tube may be scarred or destroyed, and adhesions can form that keep the tube partially or fully blocked. This scarring can prevent an egg from traveling through the tube normally, which affects the ability to conceive naturally.
Tubal damage also increases the risk of ectopic pregnancy, where a fertilized egg implants inside the fallopian tube instead of reaching the uterus. This happens because scar tissue can slow the egg’s movement enough for implantation to occur in the wrong location.
For women who have had one or both tubes removed due to pyosalpinx, in vitro fertilization (IVF) bypasses the tubes entirely and remains a viable path to pregnancy. In fact, removing a severely damaged tube before IVF can actually improve success rates, because fluid from a blocked tube can leak into the uterus and interfere with embryo implantation.
Pyosalpinx vs. Hydrosalpinx
These two conditions are closely related but represent different stages. Pyosalpinx is the active infection, with pus trapped inside the tube, inflamed and thickened walls, and acute symptoms like pain and fever. Hydrosalpinx is what can happen afterward: the pus gets reabsorbed, the infection resolves, but the tube stays dilated and filled with clear fluid because the blockage remains.
Both conditions impair the function of the affected tube. The key difference is urgency. Pyosalpinx is an active, potentially dangerous infection that needs prompt treatment to prevent rupture and spread. Hydrosalpinx is a chronic condition that doesn’t carry the same immediate risk but still affects fertility and may require surgical management depending on your reproductive goals and age.