Definition

Pelvic Inflammatory Disease (PID) is an infection and inflammation of the upper female reproductive organs, including the uterus, fallopian tubes, and ovaries. This condition is primarily caused by sexually transmitted infections (STIs) such as chlamydia and gonorrhea.

Bacteria responsible for STIs travel upward to the uterus, leading to infection. However, in some rare cases, non-sexually transmitted infections can also cause this disease.

PID most commonly occurs in sexually active women aged 15–25 years. The exact number of cases is hard to determine, but in high-income countries, it is estimated that there are 10-20 cases per 1,000 women of reproductive age. The World Health Organization (WHO) states that sexually transmitted infections are among the top five diseases most commonly experienced by adults.

Causes

Approximately 85% of PID cases are caused by bacteria such as Neisseria gonorrhoeae (the cause of gonorrhea) and Chlamydia trachomatis (the cause of chlamydia). These bacteria are typically acquired through unprotected sexual intercourse. Around 10–20% of untreated chlamydia and gonorrhea infections will develop into PID.

Clinically, PID caused by gonorrhea tends to present with more severe symptoms compared to other causes. PID caused by chlamydia often does not show symptoms but can still lead to severe long-term complications.

Other microbes that can cause PID include:

• Mycoplasma genitalium
• Trichomonas vaginalis
• Herpes simplex virus 2 (HSV-2)
• Bacteria causing bacterial vaginosis (Gardnerella vaginalis, Peptostreptococcus, Bacteroides)
• Respiratory pathogens (Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus aureus)
• Intestinal bacteria (Escherichia coli, Bacteroides fragilis, group B Streptococcus)

These pathogens account for approximately 15% of PID cases. Additionally, people with HIV/AIDS are known to be at higher risk for PID. The occurrence is attributed to the correlation between HIV infection and a heightened prevalence of certain STIs, including chlamydia and Candida yeast infections, which may eventually progress to PID.

In other cases, bacteria may enter the reproductive organs when the protective mechanism of the cervix is disrupted. This can occur during menstruation, after childbirth, miscarriage, or abortion. Bacteria can also enter during the insertion of an intrauterine device (IUD) or other medical procedures involving the insertion of instruments into the uterus.

Risk Factor

Several risk factors for PID include:

• Being sexually active and under 25 years old
• Having multiple sexual partners
• Having sexual intercourse with someone who has multiple sexual partners.
• Having sex without using a condom.
• Regularly douching, which disrupts the balance of good and bad bacteria in the vagina, makes infection more likely.
• Having a history of PID or previous STIs. If you've had PID before, you're at higher risk of getting it again.
• Using an intrauterine device (IUD). The risk of PID is highest during the first three weeks after IUD insertion, though it is rare (9.6 cases per 1,000 insertions). If PID occurs, the IUD does not need to be removed unless symptoms persist after treatment.

Symptoms

You may not realize you have PID because it can cause mild symptoms or none at all. However, if symptoms are present, you might experience:

• Pain in the lower abdomen, which may vary in intensity from mild to severe. The pain is typically dull, throbbing, or cramping, occurs on both sides of the abdomen, and is continuous. It usually begins after the first day of the last menstrual period and worsens with movement, exercise, or intercourse
• Pelvic pain
• Foul-smelling vaginal discharge
• Bleeding after intercourse
• Fever >38°C, sometimes accompanied by chills
• Nausea and vomiting
• A burning sensation or pain when urinating
• Vaginal bleeding between periods

Not all symptoms may be present in cases of PID. Gonorrhea-related PID often causes more severe symptoms.

Diagnosis

There is no specific examination that can diagnose PID. The diagnosis is primarily clinical, meaning it is based on your symptoms, medical history, and physical examination.

Laboratory tests and imaging, such as ultrasound or CT scan, can help confirm the diagnosis. However, a negative result does not rule out PID, so your doctor may still treat you based on clinical characteristics.

Your doctor will ask about your symptoms. PID is often suspected in women under 25 who are menstruating, have multiple sexual partners, do not use contraception, and live in areas with high rates of STIs. Clearly describe your symptoms and risk factors.

Your doctor will also ask about the duration of your pain. PID pain usually lasts less than 7 days. If it lasts longer than 3 weeks, your doctor may consider other diagnoses.

To support the diagnosis, your doctor may perform a physical examination, including an external and internal genital exam and a bimanual examination. An internal genital exam may involve using a speculum, an instrument inserted into the vagina to widen it so the cervix can be clearly seen.

In PID, there may be discharge from the cervix. The bimanual examination involves inserting two fingers into the vagina while the other hand presses on the lower abdomen to detect pain from pressure on the uterus, cervix, and ovaries.

Other tests may include:

• Blood tests
• A pregnancy test to rule out ectopic pregnancy, which can also cause pelvic pain
• Testing for gonorrhea and chlamydia, with samples taken from the cervix via swab or from urine, then examined in a laboratory. A bacterial culture may also be performed
• Urine tests to rule out a urinary tract infection, which can cause pelvic pain
• Ultrasound (USG)

In some cases, your doctor may also perform:

• Endometrial biopsy, which involves taking and examining a sample from the endometrium (the inner layer of the uterus)
• Laparoscopy, where a small incision is made in the abdomen and a special instrument is used to directly view the reproductive organs
• Culdocentesis is a rarely performed procedure where a needle is inserted into the back of the vagina to collect fluid from the pelvic cavity for laboratory examination

Management

PID can be treated, but treatment will not repair any damage already caused by the infection. Therefore, the longer you delay seeking medical help, the greater your risk of developing complications from the disease.

Your doctor may prescribe antibiotics to treat PID. Even if your symptoms improve, you should finish the entire course of antibiotics prescribed by your doctor. Make sure your sexual partner also undergoes STI testing and is treated if the test is positive. You and your partner should avoid sexual intercourse until treatment is completed.

However, if there is no improvement after treatment, you show severe symptoms, or you have an abscess in the pelvic cavity, you may need to be hospitalized. In rare cases, surgery may be required to treat the infection. Surgery may be needed if an abscess has ruptured or if your doctor believes an abscess is about to rupture, requiring surgery to clean and stop the spread of the infection.

Complications

Untreated PID can lead to scarring and abscess formation, causing permanent damage to the reproductive organs.

Complications can include:

• Ectopic pregnancy. PID is a leading cause of ectopic pregnancy.
• Infertility. Damage to the reproductive organs can cause infertility. The more times you have PID, the higher your chances of infertility.
• Chronic pelvic pain. PID can cause pelvic pain that lasts for months or years.
• Tubo-ovarian abscess. Pus-filled abscesses can form in your reproductive organs, typically in the fallopian tubes and ovaries but also in the uterus. If untreated, these abscesses can lead to life-threatening infections.

Prevention

You can prevent PID by following these steps:

• Practice safe sex. Use condoms every time you have sex, limit your number of sexual partners, and ask your partner about their sexual history.
• Discuss contraception with your doctor. Many contraceptive methods do not protect against STIs. If you use birth control pills or an IUD, you should still use condoms during sex to avoid STIs.
• Get tested. If you are at high risk, regular STI screening is recommended. Early detection and treatment of infections such as chlamydia, gonorrhea, and syphilis can prevent complications, including PID. If you have PID, ask your partner to get tested as well to stop the spread.
• Avoid douching. Washing your vagina with water or chemical mixtures can disrupt the balance of bacteria in your vagina, making you more susceptible to STIs.

When to See a Doctor?

Seek medical attention immediately if you experience:

• Severe pain in the lower abdomen or pelvis
• Nausea and vomiting
• Fever >38°C
• Foul-smelling vaginal discharge

Even if your symptoms are mild, see a doctor to avoid complications. You should also seek treatment if you have symptoms of an STI, such as foul-smelling vaginal discharge, pain when urinating, and vaginal bleeding between periods. Early treatment of STIs can prevent PID.

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