Pelvic inflammatory disease (PID) is a clinical syndrome in women resulting from infection of the usually sterile upper genital tract. PID is an important condition to recognise and treat, as significant complications such as infertility or ectopic pregnancy may ensue.

The diagnosis encompasses the following entities, either in isolation or combination:

  • ●          Endometritis, (including postpartum)
  • ●          Salpingitis
  • ●          Tubo-ovarian abscess
  • ●          Pelvic cellulitis/ peritonitis
  • ●          Chorioamnionitis and intra-amniotic syndrome

PID presents in two principle forms:

  • Sexually acquired:
    • Note that some terminology reserves the term PID exclusively for sexually acquired infection.
  • Non-sexually acquired:
    • Often secondary to gynaecological surgery or complications of pregnancy.

PID is an important condition to recognise and treat, as significant complications such as infertility or ectopic pregnancy may ensue.



Sexually acquired:

  • ●          N. gonorhoeae.
  • ●          C. trachomatis, (now the most common STD cause of PID in Australia).
  • ●          Mycoplasma genitalium.

Non-sexually acquired:

  • ●          Polymicrobial with both aerobic and anaerobic organisms.

Note that, even with sexually transmitted infections the resultant upper tract infection is usually polymicrobial with mixed STD pathogens and endogenous flora, and hence empirical treatment will need to be broad-spectrum and include cover for anaerobic pathogens. 1

Risk factors:

There are two predominant predisposing factors:

  • 1.         Sexually transmitted disease, (STD)
  • 2.         Mechanical disruption of the cervical barrier, including:
  • ●          Childbirth
  • ●          Instrumentation:
  •             ♥          IUDs
  •             ♥          Termination of pregnancy
  •             ♥          Dilation and curettage.
  •             ♥          Septic abortions (secondary to non-medical/ non-aseptic attempts at                                   pregnancy termination).


There is a high incidence of significant sequelae in untreated PID, including:

  • ●          Chronic infection with chronic pelvic pain.
  • ●          Infertility, the risk of this increases with the number of episodes of PID.
  • ●          Increased risk of ectopic pregnancy.
  • ●          Fitz-Hugh Curtis syndrome:
  • ♥          Rarely patients may present with RUQ pain, due to Fitz-Hugh Curtis syndrome, although this is usually an incidental finding in patients with PID.
  • ♥          It is due to a perihepatitis and a focal peritonitis secondary to the spread of inflammatory peritoneal fluid to the sub-phrenic and sub-diaphragmatic spaces.
  • ♥          Other causes of biliary tract disease will need to be excluded before this diagnosis is made.

Clinical Features

The diagnosis of PID is imprecise. It is usually based on a combination of:

  • ●          Known risk factors
  • ●          The clinical presentation
  • ●          Investigations

Important point of history:

  • 1.         Abdominal or pelvic pain.
  • 2.         Assess for risk factors:
  • ●          Sexual activity
  • ●          Recent childbirth
  • ●          Recent instrumentation.
  • 3.         Abnormal vaginal discharge.
  • 4.         Dyspareneunia

Important point of examination:

  • 1.         Fever:
  • ●          This may indicate more severe disease, but its absence does not exclude PID.
  • 2.         PV examination:
  •             Mucopurulent discharge:
  • ●          The presence of muco/purulent discharge (or the presence of WBCs on      microscopy), is a sensitive marker for PID.
  •             If the discharge appears normal and there are no WBCs seen on a wet slide            preparation, then PID is a less likely diagnosis.   
  •             Adnexal tenderness:
  • ●          This is the most sensitive examination finding, but has extremely low sensitivity. 
  • 3.         Cervical motion tenderness (cervical “excitation”).
  • ●          There is tenderness on cervical “rocking” toward the side of the pathology.


Blood tests:

  • 1.         FBE
  • 2.         CRP
  • 3.         U&Es/ glucose.
  • 4.         Beta HCG
  • ●          The possibility of ectopic pregnancy must always be considered in the        differential diagnosis of any female of child bearing age who presents with       pelvis pain and/ or abnormal bleeding.
  • ●          PID is uncommon in pregnancy, but has significant implications if present.


To help rule out UTI as a differential diagnosis

PCR testing:

Urine and/or swabs For:

  • ●          N. gonorhoeae
  • ●          C. trachomatis.
  • ●          M. genitalium (if available).


Cervical cultures for N. gonorhoeae or C. trachomatis, (useful for antibiotic sensitivity testing, which PCR testing will not be able to assess).


Ultrasound may detect suggestive but non-specific features of PID such as free fluid in the Pouch of Douglas.

It is more useful in more severe disease, where it can detect significant complications such as  tubo-ovarian abscess.

It is also useful to help rule out other causes of pelvic pain such as complicated ovarian cysts, (torsion or hemorrhage).


This has traditionally been taken as the ultimate the gold standard investigation.

It has a specificity that approaches 100 %, however, it cannot diagnose early/ milder disease and so sensitivity is only around 50- 80 %. 

It is useful in unwell patients, when diagnosis is uncertain or in the setting of acute, recurrent or chronic abdominal pain of uncertain diagnosis.


  • 1.         Analgesia: Simple oral analgesia is usually sufficient, occasionally titrated opioid may be       require for more severe cases.
  • 2.         Foreign material. It is vital that any IUCD or retained products of conception be removed as                 soon as possible.
  • 3.         Antibiotics:

Non-sexually acquired pelvic inflammatory disease: 1

For mild to moderate infection, use:

●          Amoxycillin + clavulanate 875 + 125 mg orally, 12-hourly for 14 days


●          Doxycycline 100 mg orally, 12-hourly for 14 days

Plus either:

●          Azithromycin 1 g orally, as a single dose 1 week later (azithromycin should be      used in pregnancy or breastfeeding)


●          Doxycycline 100 mg orally, 12-hourly for 14 days.

For severe disease (related to pregnancy/ surgery and unlikely to be sexually acquired):

●          Amoxy/ampicillin 2 grams IV, 6-hourly


          Gentamicin 4 to 6 mg/kg IV, daily (adjust dose for renal function)


●          Ceftriaxone 2 grams IV, daily


●          Metronidazole 500 mg IV, 12-hourly.

Continue until there is substantial clinical improvement, then use oral amoxicillin + clavulanate plus doxycycline (as for mild to moderate infection above) to complete at least 2 weeks of treatment.

Sexually acquired pelvic inflammatory disease:

Early empirical treatment of sexually acquired pelvic inflammatory disease is important because it reduces complications such as infertility.

Infection is usually initiated by Chlamydia trachomatis and/or Neisseria gonorrhoeae, and possibly Mycoplasma genitalium, although other organisms from the endogenous vaginal flora may subsequently be involved.

Sexual partners should be examined, investigated and treated empirically.

For mild to moderate infection, use:

          Ceftriaxone 500 mg IM or IV, as a single dose (for gonorrhoea)


          Metronidazole 400 mg orally, 12 hourly for 14 days


          Azithromycin 1gram orally, as a single dose

Plus either:

          Doxycycline 100 mg orally, 12 hourly for 14 days

Or (for women who are pregnant or patients suspected to be non-adherent to doxycycline):

          An additional dose ofAzithromycin 1gram orally, 1 week later.

For severe infection use:

●          Ceftriaxone 2 grams IV, daily (or cefotaxime 2 grams IV 8 hourly).


●          Azithromycin 500 mg IV, daily


●          Metronidazole 500 mg IV, 12-hourly

For full antibiotic prescribing details, and alternative regimes, see latest edition of the Antibiotic Therapeutic Guidelines.


Most patients who have PID may be managed as outpatients.

Indications for Admission include:

●          Clinically severe disease:

♥          Intractable pain

♥          Complications such as abscess formation, peritonitis, septicemia.

●          Diagnosis uncertain and when other urgent surgical conditions, such as appendicitis or      ectopic pregnancy need to be ruled out.

●          Significant co-morbidity such as pregnancy or diabetes.

●          Oral antibiotics not appropriate because of vomiting or unpredictable compliance. This     is important especially in adolescents where consequences may be significant.


●          Any patient discharged on oral medication, should be reviewed within 24 – 48 hours to     assess the response to therapy.




Fellowship Notes

Dr Lucy J Yarwood LITFL author

MSc, MBChB University of Manchester. Currently doctoring in sunny Western Australia, aspiring obstetrician and gynaecologist

Dr Jessica Hiller LITFL Author

Doctor at Sir Charles Gairdner Hospital in Western Australia. Graduated from Curtin University in 2023 with a Bachelor of Medicine, Bachelor of Surgery. I am passionate about Obstetrics and Gynaecology, with a special interest in rural health care.

Physician in training. German translator and lover of medical history.

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