Pelvic Inflammatory Disease

Pathophysiology

Pelvic inflammatory disease refers to an infective inflammation of the endometrium, uterus, fallopian tubes (salpingitis), ovaries and peritoneum. It is caused by the spread of bacterial infection from the vagina or cervix to the upper genital tract.

Chlamydia trachomatis and Neisseria gonorrhoea are responsible for approximately 25% of cases, with other bacteria such as Streptococcus, bacteriodes and anaerobes also implicated.

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Fig 1
Pelvic inflammatory disease refers to infection of the upper female genital tract.

Risk Factors

The risk factors for pelvic inflammatory disease include:

• Sexually active
• Aged under 15-24
• Recent partner change
• Intercourse without barrier contraceptive protection
• History of STIs
• Personal history of pelvic inflammatory disease

Pelvic inflammatory disease can also occur via instrumentation of the cervix – inadvertently introducing bacteria into the female reproductive tract. Such procedures include gynaecological surgery, termination of pregnancy, and insertion of an intrauterine contraceptive device.

Clinical Features

The signs and symptoms of pelvic inflammatory disease are elicited from the medical and sexual history, and a gynaecological examination. Whilst it can be asymptomatic, symptoms include:

• Lower abdominal pain
• Deep dyspareunia (painful sexual intercourse)
• Menstrual abnormalities (e.g menorrhagia, dysmenorrhoea or intermenstrual bleeding)
• Post-coital bleeding
• Dysuria (painful urination)
• Abnormal vaginal discharge (especially if purulent or with an unpleasant odour)

In advanced cases, women can experience severe lower abdominal pain, fever (>38° C), and nausea and vomiting.

On vaginal examination, there may be tenderness of uterus/adnexae or cervical excitation (on bimanual palpation). There may be a palpable mass in the lower abdomen, with an abnormal vaginal discharge noted.

By TeachMeSeries Ltd (2026)

Fig 2
Mucopurulent cervical discharge, a feature of pelvic inflammatory disease.

Differential Diagnosis

The differential diagnoses for pelvic inflammatory disease include:

• Ectopic pregnancy (a pregnancy test is mandatory to exclude this).
• Ruptured ovarian cyst
• Endometriosis
• Urinary tract infection

Investigations

The initial investigations in suspected pelvic inflammatory disease involves identifying the infective organism.

Endocervical swabs should be taken to test for gonorrhea and chlamydia, and a high vaginal swab for trichomonas vaginalis and bacterial vaginosis. In the UK, testing is via nucleic acid amplification (NAAT). Negative swabs do not exclude the diagnosis.

Further investigations include:

• Full STI screen – (HIV, syphilis, gonorrhoea and Chlamydia as a minimum) should be offered to all women with PID.
• Urine dipstick +/- MSU – to exclude urinary tract infection.
• Pregnancy test – to exclude pregnancy.
• Transvaginal ultrasound scan – if there is severe disease or diagnostic uncertainty.
• Laparoscopy –  used to observe gross inflammatory changes, and to obtain a peritoneal biopsy. This is indicated only in severe cases where there is diagnostic uncertainty.

By TeachMeSeries Ltd (2026)

Fig 3
Neisseria gonorrhoea can also be identified on microscopy, with a diplococci shape.

Management

The mainstay in the management of pelvic inflammatory disease is antibiotic therapy.

Treatment is a 14-day course of broad spectrum antibiotics with good anaerobic coverage. This should be commenced immediately, before the results of swabs are available. Options include:

• Doxycycline, ceftriaxone and metronidazole
• Ofloxacin and metronidazole

Analgesics such as paracetamol should be considered. The patient should be advised to rest, and avoid sexual intercourse until the antibiotic course is complete and partner(s) are treated. All sexual partners from the last 6 months should be tested and treated to prevent recurrence and spread of infection.

There are some situations in which women should be admitted to hospital:

• If pregnant and especially if there is a risk of ectopic pregnancy.
• Severe symptoms: nausea, vomiting, high fever.
• Signs of pelvic peritonitis.
• Unresponsive to oral antibiotics, need for IV therapy.
• Need for emergency surgery or suspicion of alternative diagnosis.

Complications

Delaying treatment or having repeated episodes of pelvic inflammatory disease (recurrent PID) can increase risks of serious and long term complications:

• Ectopic pregnancy – due to narrowing and scarring of the fallopian tubes
• Infertility – affects 1 in 10 women with PID.
• Tubo-ovarian abscess
• Chronic pelvic pain
• Fitz-Hugh Curtis syndrome – perihepatitis that typically causes right upper quadrant pain

By TeachMeSeries Ltd (2026)

Fig 4
Perihepatic adhesions observed on laparoscopy – a complication of PID.