• Clinical science

Pelvic inflammatory disease


Pelvic inflammatory disease (PID) is caused by a bacterial infection that spreads beyond the cervix to infect the upper female reproductive tract, including the uterus, fallopian tubes, ovaries, and surrounding tissue. The most common pathogens that cause PID are Chlamydia and Gonococci. Symptoms may vary considerably; while some women are asymptomatic, others may complain of mild pressure pain and discharge or present with signs of systemic inflammation, such as fever and severe abdominal pain. Diagnosis is based on clinical findings and may be supported by ultrasound, PCR, and/or cultures of cervical and urethral discharges. Calculated parenteral antibiotic therapy is indicated in women with suspected PID. Most common complications include infertility, ectopic pregnancy, and chronic pelvic pain.


  • Lifetime prevalence: ∼ 4.5% in women of reproductive age (18–44 years) [1]
  • > 1 million women experience an episode of PID/year. [2]
  • PID is one of the most common causes of infertility. [1]

Epidemiological data refers to the US, unless otherwise specified.


Clinical features


Diagnosis is primarily based on clinical findings. Further diagnostic tests help confirm the diagnosis, especially in ambiguous cases.

PID may manifest with symptoms of appendicitis due to periappendicitis or perihepatitis. Symptoms may also mimic ectopic pregnancy.

PID should be suspected in young, sexually active women who present with lower abdominal pain and adnexal/cervical motion tenderness.

Differential diagnoses

Differential diagnosis of lower abdominal pain in women of reproductive age
Disorder Clinical features Diagnostic clues Therapy
Ectopic pregnancy
  • Cervical discharge
  • CMT
Kidney stones
  • Unilateral colicky flank pain
  • Pain may radiate to the lower abdomen and genital area.
  • Destruction or removal of stone
Ovarian cyst rupture
  • Sudden onset unilateral lower abdominal pain
  • Usually after physical activity (exercise, sexual intercourse)
  • Minimal vaginal bleeding (spotting) can occur.
Ovarian torsion

Cervicitis [11]

The differential diagnoses listed here are not exhaustive.


Empirical antibiotic therapy (also consider coinfections) [3][1]

It is better to overtreat rather than delay treatment if PID is suspected.


We list the most important complications. The selection is not exhaustive.