Pelvic inflammatory disease

Pelvic inflammatory disease (PID) is an infection of the female reproductive organs. It’s usually passed from the vagina or the cervix to the upper genital tract, where it can affect the uterus, fallopian tubes, ovaries, or the lower abdomen (NHS, 2022; Royal College of Obstetricians and Gynaecologists (RCOG), 2022).

Although PID is common the exact incidence rates are unknown. Figures suggest that in the UK, around one in 50 sexually active women develops PID every year, with those aged between 15 and 24 most commonly affected (NHS Leeds, 2022).

Many people do not experience any obvious symptoms, but among those who do, the most common symptom is pain in the abdomen, which can vary from mild to severe and may spread down to the legs (LTH Trust, 2022).

Other symptoms are usually mild. They include:

• pain or discomfort during sex, often experienced deep in the pelvic area
• pain when urinating
• abnormal bleeding (after sex, in between periods, heavier periods)
• pain during menstruation
• unusual vaginal discharge (yellow or green-coloured, offensive smelling)
• high temperature
• lower back pain
• nausea and vomiting (Harding, 2018).

Symptoms can develop slowly over time – for example, patients might notice mild pelvic pain that is not overly bothersome but persists for a few weeks. Some people develop symptoms very quickly and can get quite ill within a few days.

According to the National Institute for Health and Clinical Excellence, pelvic inflammatory disease is almost always caused by a sexually transmitted infection, with chlamydia responsible for up to 35% of cases (NICE, 2022a). Other sexually transmitted inections that can often cause PID are gonorrhoea and Mycoplasma genitalium, sometimes called M-gen.

Pelvic inflammatory disease is not always the result of a sexually transmitted infection. The vagina contains unharmful bacteria that do not themselves cause any problems, but sometimes these bacteria can travel through the cervix to the upper female reproductive organs, where they can cause infection.

That can happen unprompted and spontaneously, or as a result of some kind of interruption to the cervix’s barrier, for example if an instrument is passed into the uterus during a medical procedure such as:

• childbirth
• hysterosalpingography (HSG), an x-ray examining the inside of the uterus and fallopian tubes
• insertion of an intrauterine contraceptive device

It is important that pelvic inflammatory disease is identified and treated early to avoid complications. There is no single test to diagnose PID, so diagnosis is made on the basis of the presence of symptoms and by taking a clinical and sexual history.

A number of tests can be carried out, including (Harding, 2018; NICE 2022b):

• internal vaginal/pelvic examination
• abdominal examination to check for tenderness and pain
• swabs of the cervix and urethra
• blood and urine tests (negative swabs do not necessarily rule out PID)
• screening for STIs including chlamydia, gonorrhoea, M-gen, HIV and syphilis
• pregnancy test to check for ectopic pregnancy
• laparoscopy (not routinely – in severe cases, where problems persist despite treatment, or to rule out other causes of symptoms, such as appendicitis).

Most cases of pelvic inflammatory disease can be successfully treated with a course of antibiotics, usually for around 2 weeks. If PID is suspected, treatment is often initiated immediately in anticipation of any test results to prevent complications.

There are a few different antibiotics that may be prescribed to cover a number of possible bacteria that could be the cause of PID. Often, a single dose of one antibiotic is given by intramuscular injection, followed by a course of one or two other oral antibiotics (Harding, 2018; NICE, 2022c).

Patients can also take over-the-counter painkillers as needed to treat pain and discomfort.

In certain cases of suspected PID, the person should be urgently admitted to hospital. This includes if the patient is or could be pregnant, as it’s important to promptly diagnose or rule out complication like ectopic pregnancy.

People with suspected PID who have acute symptoms, such as a

As a first step (and if appropriate) the patient should be referred to a genitourinary medicine or sexual health clinic for sexual health screening, advice and contact tracing. If pelvic inflammatory disease is confirmed, any current and recent sexual partners – within the last 6 months – should be traced and managed (NICE, 2022c).

Importantly, remind patients that the source of PID is not always a sexually transmitted infection, and it can develop in long-term, monogamous sexual relationships. It is less likely to recur in cases where both partners are treated at the same time as each other (NHS, 2022b).

Patients can prevent or minimise the risk of reinfection by completing their prescribed course of treatment and practising safe sex.

References

Harding, M. Pelvic Inflammatory Disease. 2018. https://patient.info/womens-health/pelvic-pain-in-women/pelvic-inflammatory-disease#nav-0 (accessed 23 May 2022)

Leeds Teaching Hospitals NHS Trust. 2022. https://www.leedsth.nhs.uk/a-z-of-services/acute-gynaecology-services/common-conditions/pelvic-inflammatory-disease/ (accessed 23 May 2022)

NHS. Overview – Pelvic inflammatory disease. 2022a. https://www.nhs.uk/conditions/pelvic-inflammatory-disease-pid/ (accessed 23 May 2022)

NHS. Treatment – Pelvic inflammatory disease. 2022b. https://www.nhs.uk/conditions/pelvic-inflammatory-disease-pid/treatment/ (accessed 23 May 2022)

NHS. Complications – Pelvic inflammatory disease. 2022c. https://www.nhs.uk/conditions/pelvic-inflammatory-disease-pid/complications/ (accessed 23 May 2022)

National Institute for Health and Care Excellence. Pelvic inflammatory disease: summary (CKS) 2022a. https://cks.nice.org.uk/topics/pelvic-inflammatory-disease/ (accessed 23 May 2022)

National Institute for Health and Care Excellence. Pelvic inflammatory disease: What investigations are advised in a woman with suspected pelvic inflammatory disease? (CKS) 2022b. https://cks.nice.org.uk/topics/pelvic-inflammatory-disease/diagnosis/investigations/ (accessed 23 May 2022)

National Institute for Health and Care Excellence. Pelvic inflammatory disease: Scenario: Management of pelvic inflammatory disease. (CKS) 2022c. https://cks.nice.org.uk/topics/pelvic-inflammatory-disease/management/management/ (accessed 23 May 2022)

Royal College of Obstetricians and Gynaecologists. 2022. https://www.rcog.org.uk/for-the-public/browse-all-patient-information-leaflets/acute-pelvic-inflammatory-disease-pid-tests-and-treatment-patient-information-leaflet/ (accessed 23 May 2022)