Pelvic Inflammatory Disease

Core

What is Pelvic Inflammatory Disease?

Pelvic inflammatory disease (PID) is a condition caused by the spread of infection from the lower reproductive tract to the upper reproductive tract of the female. This means that the symptoms depend on level of infection and present in a predictable manner as infection spreads.

Initially the vaginal infection spreads to the cervix. This causes inflammation and tenderness causing symptoms such as deep dyspareunia (painful intercourse) and possible post-coital bleeding. It can also lead to cervical discharge, which can cause changes in vaginal discharge.

The infection can then spread into the uterus, causing menstrual irregularity (intermenstrual bleeding) as well as heavy and painful periods.

If the infection spreads into the Fallopian tubes, it causes salpingitis (inflammation), leading to abdominal pain. This inflammation can damage the fallopian tubes by causing stricture formation and reduced function of cilia that normally waft the ovum towards the uterus. This can lead to infertility and an increased risk of tubal ectopic pregnancy. If the infection is contained there is a risk of developing tubo-ovarian abscesses.

As the ends of the fallopian tubes are open into the peritoneal cavity there is a path for infection to extend out of the Fallopian tube and into the peritoneal cavity. This can cause intra-abdominal complications such as peritonitis, perihepatitis (known as Fitz-Hugh-Curtis Syndrome) and sigmoiditis.

Causes

Pelvic inflammatory disease most commonly develops as a consequence of an untreated or missed sexually transmitted infection (STI). The risk of missing STIs in women is relatively high, as many STIs are asymptomatic in women. This means that both participation in partner notification programmes and engaging with sexual health clinics after having unprotected sexual intercourse (UPSI) is key to detect infection.

• Chlamydia trachomatis (chlamydia infection) is the most common STI cause.
• Neisseria gonorrhoeae (gonorrhoea infection).
• Not all cases are due to STIs as normal vaginal flora can also be responsible.
• In the remaining cases, there is no causative organism, and this is known as pathogen-negative PID.

Risk Factors

Risk factors for PID are mainly in two groups:

1. Factors that increase the likelihood of contracting an initial infection:
   
   1. Young age
   2. Recent change in sexual partners
   3. History of multiple sexual partners
   4. Young age at first intercourse
2. Factors that increase the chances of an existing vaginal infection ascending to the upper reproductive tract:
   
   1. Termination of pregnancy
   2. Insertion of intrauterine device (IUD) or intrauterine system (IUS), particularly in the weeks following insertion
   3. Hysterosalpingography (imaging of the womb and Fallopian tubes using contrast and X-rays)
   4. In vitro fertilisation (IVF) or intrauterine insemination

Presentation

PID can present with any, all or none of the following symptoms:

• Pelvic or lower abdominal pain, commonly bilateral.
• Deep dyspareunia (pain on deep penetration of the vagina).
• Abnormal vaginal bleeding (inter-menstrual, post-coital or breakthrough bleeding) - secondary to cervicitis or endometritis.
• Abnormal vaginal or cervical discharge.
• Due to the possible involvement of the Fallopian tubes, PID can also present with reduced fertility. This is because the inflammation can lead to stricture formation, or ciliary dysfunction (meaning the egg is not effectively wafted towards the uterus).

Most women have only mild symptoms meaning the condition can easily be missed.

Examination and Investigations

In any woman presenting with possible PID, it is important to perform an abdominal and a vaginal examination. This may demonstrate lower abdominal tenderness, cervical motion tenderness (pain on manual pressure on the cervix), or uterine tenderness (pain on bimanual examination).

There are a number of important investigations that need to take place to diagnose PID. However, a clinical diagnosis without the results of these tests can be made.

• Pregnancy Test - this will help to exclude ectopic pregnancy, which may be causing similar symptoms.
• STI Screen - vaginal or endocervical swabs with NAAT for chlamydia and gonorrhoea to help identify if an infection is present (which would make PID more likely). It is important to remember though that not all PID is caused by an STI, so negative swabs do not rule out PID.
• Examination for the presence of pus on a smear of vaginal cells - the presence of pus may support a diagnosis, but its absence does not exclude PID.
• Blood Tests - the following blood tests can be used to support a possible diagnosis of PID, but having positive results does not necessarily indicate PID as they may be positive for other reasons:
  
  • C-reactive Protein (CRP)
  • Leucocyte count

Treatment

The most important things to think about when treating PID are analgesia (pain relief), antibiotics to treat the infection, and contact tracing (this only applies if the cause of PID has been identified as an STI).

Prevention

Primary Prevention - prevention of STI contraction, e.g. sex and relationships education in schools, use of barrier contraception.

Secondary Prevention - screening for STIs when asymptomatic.

Tertiary Prevention - prevention of the complications of PID through swift diagnosis and treatment, and treating any partners to avoid reinfection.

Edited by: Dr. Ben Appleby

Reviewed by: Dr. Thomas Burnell

Quiz

Preview the Pelvic Inflammatory Disease quiz