Pelvic inflammatory disease (PID)
Information for students
Definition
Causes
Statistics
Signs and symptoms
Transmission and risk factors
Consequences
Testing
Treatment
Prevention
PID refers to the acute clinical syndrome attributed to
the ascending spread of infection in women from the vagina and endocervix
to the endometrium (lining of the uterus), fallopian tubes, and/or
adjoining structures.
The ascent of infection has three stages:
- Infection of the cervix (cervicitis), which can lead
to
- Infection of the endometrium (endometritis) and
eventually to
- Infection of the fallopian tubes (salpingitis).
Symptoms are not always obvious, and because PID is
common among sexually active women, it is often known as the "silent
epidemic".
As already mentioned, PID can be caused by Chlamydia
trachomatis and Neisseria gonorrhoeae, and also by other infectious
agents.
Chlamydia is
responsible for about 50% of PID cases, and gonorrhoea
is the cause in 25% of cases. In young women
with lower genital tract chlamydial infection the risk of developing salpingitis
is one in 12, and one in 10
for women with gonorrhoea.
Non-gonococcal urethritis is the most common STD among
Australian men. Chlamydia has been found to be the infectious agent in up to 70% of
men with non-gonococcal urethritis, and in up to 80% of men with a related
syndrome, post-gonococcal urethritis.
Each year in Australia an estimated 10,000
women are treated for PID as in-patients in hospitals, but as many as 10
to 30 times that number may be treated as outpatients or suffer more
subtle forms of infection. It has also been estimated that chlamydia, the
major cause of PID, costs between $75 million and $150 million a year in
Australia.
There have been no Australian studies to estimate actual
prevalence, however it is known that in the USA PID affects an estimated 4
million women each year, with a yearly cost of $3 billion. One in five
women is hospitalised, and surgery is needed in one in 10 cases. There are
26,000 ectopic pregnancies each year in the USA as a result of
salpingitis, and 200,000 women are left infertile.
Symptoms can include:
- lower abdominal pain or tenderness
- menstrual disturbances
- dysuria (burning on urination)
- a change in smell, colour, or amount of vaginal
discharge
- deep pain during sexual intercourse
- fever
PID is usually caused by a sexually transmitted
infection, but gynaecological
surgical procedures such as abortion or the insertion of an intra-uterine
device (IUD) can cause the infectious agents to spread upwards from the cervix
and vagina. In Sweden it was found that 12% to 14% of all PID cases had
been caused by gynaecological procedures within 6 weeks of admission.
IUDs may increase the risk of PID because the string
attached to the device which extends down into the vagina acts as a wick
for infection, allowing bacteria to ascend more easily into the upper
genital tract. The relative risk of PID for sexually active young women
using IUDs is 1.5 (i.e. a risk of PID one-and-a-half times greater than
for young women not using IUDs). Those using barrier methods (i.e. condoms
and diaphragms) have a relative risk of PID of 0.6 (i.e. the chance that
they will acquire PID is about half that of those who do not use barrier
methods).
The use of oral contraception appears to have a
protective effect among sexually active young women with a relative risk
of 0.3 (one-third the risk of those who do not use oral contraception). It
is believed that the influence of progestogen on cervical secretions may
prevent the ascent of microbes, as it does for sperm. However, these data
were collected in the 1970s when higher dose pills were in use, and the
protective effect of the currently more commonly used low-dose pills is
not known.
PID can have devastating consequences. Salpingitis is
the most frequent long-term complication because it can cause scarring of
the tubes and infertility, making it impossible for the fertilised ovum to
pass through the tube to the uterus.
One episode of PID doubles the risk of tubal
infertility, and even a single attack can bring a seven fold increase in
the chances of ectopic pregnancy. It has been estimated that one attack of
PID carries a 20% risk of tubal blockage, rising to 30% after a second
episode and as high as 75% after three or more episodes.
On the basis of these results it has been estimated
that, of the theoretical group of women born in 1955, 15,000 per 100,000
would have had PID, and 2,000 per 100,000 would be infertile by their 30th
birthday.
If untreated, PID can lead to chronic pain and sometimes
severe disability.
Testing for the major causative organisms must be
undertaken. However, sometimes laparoscopy (investigation by minor
surgery) will be required to correctly diagnose PID.
Outpatient care may be sufficient for women with mild
symptoms, but hospitalisation is necessary for women with more severe
infection. Because PID can be caused by a variety of agents, drug
treatments should be used that are active against a broad range of
pathogens. Amoxycillin (penicillin) and doxycycline are usually
prescribed.
It is imperative that regular male partners are tested
for STDs and
treated if necessary. In men, symptoms can be mild or non-existent so they
may not present for testing or treatment.
- The use of condoms during penetrative sexual (vaginal
or anal) intercourse.
- The use of condoms if an IUD is in place.
- Sexual practices other than intercourse carry less
risk of transmitting the infections that cause PID.
- Where infection has occurred, it is important to
avoid sexual contact involving the genitals during the course of
treatment until a negative test result is obtained. This will aid
healing and prevent transmission.
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