Pelvic inflammatory disease

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.

Pathophysiology

Organisms:

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).

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.   
3. Adnexal tenderness:
   • This is the most sensitive examination finding, but has extremely low sensitivity. 
4. Cervical motion tenderness

Investigations

Blood tests

• FBE
• CRP
• U&Es/ glucose.
• 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 pelvic pain and/ or abnormal bleeding.
  • PID is uncommon in pregnancy, but has significant implications if present.

Urine

To help rule out UTI as a differential diagnosis

PCR testing

Urine and/or swabs For:

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

Microbiology

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

Ultrasound

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).

Laparoscopy

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.

Management

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
    Plus
  • 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)
    Or
  • 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
    Plus
  • Gentamicin 4 to 6 mg/kg IV, daily (adjust dose for renal function)
    Or
  • Ceftriaxone 2 grams IV, daily
    Plus
  • Metronidazole 500 mg IV, 12-hourly.

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)
    Plus
  • Metronidazole 400 mg orally, 12 hourly for 14 days
    Plus
  • 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 of Azithromycin 1gram orally, 1 week later.
• For severe infection use:
  • Ceftriaxone 2 grams IV, daily (or cefotaxime 2 grams IV 8 hourly).
    Plus
  • Azithromycin 500 mg IV, daily
    Plus
  • Metronidazole 500 mg IV, 12-hourly

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

Complications

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.

Disposition

Most patients who have PID may be managed as outpatients.

Indications for Admission include:

• Clinically severe disease
• 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.

Follow-up:

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

---

References

FOAMed

• Nickson C. Pelvic Inflammatory Disease (PID). CCC
• Zhang G. Fitz-Hugh Curtis syndrome. LITFL

Publications