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Pelvic Inflammatory Disease

Definitions and Key facts

Pelvic inflammatory disease, or PID, is a general term for infection in the upper genital tract (uterus, fallopian tubes and ovaries).


Endometritis implies involvement of the lining of the uterus, the endometrium and salpingitis refers to inflammation of the fallopian tubes.


Chronic PID is a long term sequela of acute or subacute infection.



  • Usually results from ascending infection from the cervix
  • Causes inflammation of the Fallopian tubes, uterus and ovaries
  • Is a common and potentially serious complication of some STIs.
  • May cause infertility, ectopic pregnancy, abscess formation and chronic pelvic pain.


      Aetiology and Epidemiology of PID

      The prevalence of PID is underreported, though is estimated at 1 - 3% of sexually active women. The incidence of PID is increasing. PID is most commonly caused by ascending infection from the vagina or endocervix, but can also occur from descending infection from organs such as the appendix.


      The microorganisms invade the columnar cells of the crypts of the cervix and can spread via lymphatics, veins, or may even travel on spermatozoa. The endometrium is first infected, and from here the infection may spread to the myometrium or to the fallopian tubes, causing acute or subacute salpingitis. Ovaries and the pelvic peritoneum may be involved in some cases.



      • PID can be caused by genital mycoplasmas, endogenous vaginal flora, aerobic streptococci, Mycobacterium tuberculosis, and STIs, typically Chlamydia trachomatis and Neisseria gonorrhoeae.
      • Chlamydia is the most common STI detected in the UK and gonorrohea cases are rising.
      • Other organisms that can cause PID are those associated with bacterial vaginosis, e.g. Gardnerella vaginalis, Mycoplasma hominis, Mobiluncus spp.


      Risk Factors for PID:  

      • Sexually transmitted infections, and their risk factors: multiple sexual partners, new sexual partner, young age (<25 years), lack of barrier contraception, lower socio-economic status. 
      • Insertion of new IUD (up to 3 weeks after insertion)
      • Termination of pregnancy
      • Postpartum endometritis


      Protective Factors

      • Use of barrier contraception
      • Use of Mirena IUS
      • Use of combined oral contraceptive pill


        Symptoms and Signs

        Investigations of PID

        No specific signs or lab tests are diagnostic. A full gynaecological history including sexual history should be taken. An abdominal examination should be carried out to assess sites of tenderness. Speculum and vaginal examination are necessary to assess adnexal masses, vaginal discharge and tenderness.


        Basic Tests

        • Pregnancy Test - PID may be confused with ectopic pregnancy
        • Cervical swabs - a positive swab for chlamydia or gonorrhoea can support the diagnosis of PID, but negative swabs do not exclude it.
        • Urinalysis - Necessary to exclude UTI
        • Bloods - ESR /CRP and white cell count may be raised in PID


        Other tests

        • Ultrasound scanning (transvaginal) may show ovarian cysts, thickened, fluid filled fallopian tubes, free fluid in the pelvis.
        • Endometrial biopsy may be able to give a definitive diagnosis.
        • Laproscopy is the best diagnostic test, and is the 'gold standard' but is invasive and not always available.

        Management of PID

        Analgesia as appropriate.


        Antibiotics. Treat as soon as PID is clinically suspected. Early treatment is likely to reduce risk of long term complications. Women should be admitted if there is diagnostic uncertainty, severe symptoms or signs, or if they fail to respond to oral therapy.

        • Outpatient regimen: 250mg ceftriaxone IM (one off dose), followed by doxycycline 100mg bd and metronidazole 400mg bd, 14 day course. Intravenous therapy for days 1-3 is recommended in women with severe clinical disease.


        Referral to GUM clinic. Consider referral for full STI screen, contact tracing and treatment of sexual partners.


        Contact tracing. C. trachomatis and N. gonorrhoeae are easily transmitted, though they may not show symptoms, especially in men. Advise patients to avoid  unprotected sexual contact until treated fully. All sexual partners within the last 6 months, (or the most recent if more than 6 months ago) should be screened. Sexual partners should be treated for chlamydial infection even if not identified on testing, but treatment for gonorrhoeal infection need only be given if N. gonorrhoeae found in patient or the partner.


        Review. Women with moderate or severe clinical findings should be reviewed after 2-3 days to ensure they are improving. Lack of response may require further investigations, IV antibiotics and/or surgical intervention.

        Complications of PID

        Subfertility: The risk is related to the number of episodes and their severity. Tubal infertility occurs in 10-12% of women after 1 episode of PID, 20-30% after two episodes and 50-60% after three episodes.


        Ectopic pregnancy: Risk is increased six to ten-fold.


        Chronic pelvic pain (>6months): in 18% of women. This is thought to be related to the number of episodes and severity and the extent of pelvic adhesions.


        Fitz-Hugh-Curtis Syndrome: In 5-15% of women with salpingitis, the infection spreads from the pelvis to the liver capsule, causing perihepatitis.


        Repeated infections: Relapse occurs in around one third.


        Pregnancy: PID is associated with increased risk of pre-term delivery and increased foetal and maternal morbidity.


        Neonate: Untreated infection of chlamydia or gonorrhoea risks ophthalmia neonatorum. Chlamydial transmission to the neonate can cause chlamydial pneumonitis.


        Pelvic inflammatory disease can also lead to:

        • Pyosalpinx - a pus filled fallopian tube, which can be seen in chronic infection.
        • Tubo-ovarian abscesses - involves both the ovary and the fallopian tube in a chronic abscess.
        • Hydrosalpinx - results from pyogenic salpingitis and produces large amounts of clear exudate with or without adhesions.
        • Chronic pelvic cellulitis -thickening and fibrosis of the connective tissues of the parametrium, distorting the position of the uterus, immobilising it and leading to deep pelvic ache, dyspareunia and backache.



        Consequences of PID. Salpingitis, ovarian cysts and adhesions.

        Prevention of PID

        Avoidance of risk:

        • Use of barrier contraception
        • Use of STI screening services
        • Nationwide Chlamydia screening programme
        • Offering of STI screen prior to IUD insertion

        Further Reading

        Drife, J., and Magowan, B., Clinical Obstetrics and Gynaecology, 2004. Elsevier Saunders Science.

        Oats, J., and Abraham, S., Fundamentals of Obstetrics and Gynaecology, 9th Edition (2010), Mosby Elsevier.

        Collins, S., Arulkumaran, S., Hayes, K., Jackson, S., and Impey, L., Oxford Handbook of Obstetrics and Gynaecology, 2nd Edition, 2008. Oxford University Press.

        Article by Patient UK:


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