What to know about septic pelvic thrombophlebitis

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Septic pelvic thrombophlebitis is a blood clot that develops due to an infection and subsequent inflammation. The blood clot blocks one or more of the pelvic veins.

Different types of infections, including bacteria and fungi, may lead to the infection. Staphylococcus aureus is the most common organism that causes septic thrombophlebitis.

Doctors divide septic pelvic thrombophlebitis into two types: ovarian vein thrombophlebitis and deep septic pelvic thrombophlebitis. Both classifications share the same processes but occur in different veins. Septic pelvic thrombophlebitis can also develop in more than one vein.

In most cases, symptoms start 2–4 days after delivery. Experts consider the condition rare. A 2021 case report notes that septic pelvic thrombophlebitis occurs in about 1 in 3,000 deliveries. It develops in approximately 1 in 800 C-sections and 1 in 9,000 vaginal deliveries.

The condition can become life threatening. The mortality rate in patients that develop septic pelvic thrombophlebitis is about 4.4%.

The cause of septic pelvic thrombophlebitis is an infection that causes an inflammatory response, which leads to the formation of a blood clot. Doctors theorize that complications with delivery or surgery may lead to an infection and pus formation in the wall of the vein, triggering the condition.

Septic pelvic thrombophlebitis most commonly occurs as a complication after childbirth. It can also develop due to pelvic inflammatory disease, endometritis, and intra-abdominal infections.

Doctors do not completely understand why it may occur in some people after childbirth. However, a combination of factors appears to make it more likely to occur after delivery.

For example, pregnancy changes the plasma levels of clotting factors, which may increase the risk of a blood clot developing. In addition, conditions before or after childbirth, such as an infection of the amniotic fluid, may increase the risk.

Researchers have identified certain factors that increase a person’s chances of developing septic pelvic thrombophlebitis, such as:

• C-section delivery: Septic pelvic thrombophlebitis occurs most often after a C-section delivery than during vaginal births.
• Age: Women under 20 years of age appear to have an increased risk of the condition.
• Race: Septic pelvic thrombophlebitis occurs more often in non-Hispanic Black individuals.
• Preeclampsia: This term refers to high blood pressure that develops during pregnancy.
• Chorioamnionitis: This is an infection of the amniotic fluid and the placenta.
• Twins: Having twins also increases the chances of developing the condition.

Symptoms typically start a few days after childbirth. They may vary slightly depending on the affected vein and may include:

• fever, which may persist even with antibiotics
• lower abdominal pain on the side of the affected vein
• back pain
• abdominal tenderness
• increased respiratory rate

Symptoms can sometimes mimic other gynecological and obstetric conditions, such as endometritis, pelvic abscess, and wound infection after a C-section.

There is no definitive laboratory test to confirm a diagnosis of septic pelvic thrombophlebitis. Instead, doctors diagnose the condition through a combination of methods, such as:

• Symptom history and physical exam: The doctor may check for lower abdominal tenderness and fever.
• Blood cultures: In some cases, blood cultures test positive for an infection, and the white blood cell count is high.
• Imaging tests: Doctors may order certain imaging tests to view pictures of the pelvic area and veins. For example, a CT scan may help detect the enlargement of an ovarian vein and possibly the presence of a blood clot in the vein. In some cases, a doctor may order an ultrasound to rule out other conditions and diagnoses.

Prompt treatment helps improve the outcome of this condition. If a person does not receive a prompt diagnosis, it can lead to life threatening complications. Possible serious complications include severe sepsis and a pulmonary embolism, which is a blood clot that moves to the lungs.

Usually, treatment includes broad-spectrum antibiotics to treat the infection. However, a 2018 care report indicates healthcare professionals are unsure about how long someone needs to continue antibiotic therapy. Some may administer antibiotics until the patient improves and remains fever free for about 48–72 hours. Other healthcare practitioners may recommend antibiotic therapy until discharge or even longer.

Doctors may also administer an anticoagulant, or blood thinner, to break up the blood clot. The duration and type of medication may vary according to their clinical judgment. Commonly, they use heparin.

A treatment plan may also include supportive care, such as medication for pain and to make the person more comfortable. Careful monitoring is also vital to ensure the antibiotics are working and the clot formation does not worsen.

Septic pelvic thrombophlebitis is a rare condition that involves the development of a blood clot in the pelvic veins. This typically occurs due to an infection and subsequent inflammation. It is most commonly a postpartum complication, primarily after a C-section. Symptoms, such as fever and lower abdominal pain, usually start a few days after childbirth.

Treatment often includes antibiotics to eliminate the infection and blood thinner medications to break up the blood clot.