Treat early, treat well are the watch words for this condition.

Pelvic inflammatory disease (PID) – inflammation of the upper genital tract – may include cervicitis, endometritis, salpingitis, tubo-ovarian abscess and pelvic peritonitis. PID usually occurs from ascending micro-organisms from the vagina and cervix, although a causative organism is not always isolated.¹ PID may result from a sexually transmitted infection, infection post-gynaecological procedure, postnatally or, rarely, from haematological spread.² Early diagnosis and treatment reduces the risk of long-term sequelae, including chronic pelvic pain and tubal factor infertility.

Epidemiology

PID is not a notifiable condition and no national surveillance or reporting requirements exist. Estimates of PID incidence are limited and are largely based on hospital admission data, which only include complicated cases. Studies suggest most PID is treated in general practice and ambulatory settings.² Recent research indicates hospitalisation for PID has decreased over the last two decades, which may be associated with increased chlamydia screening and treatment in outpatient settings.²

Pathogenesis

Sexually transmitted organisms, particularly Chlamydia trachomatis and Neisseria gonorrhoeae account for the majority of PID infections, however PID is usually polymicrobial with other vaginal flora, including Gardnerella vaginalis, Haemophilus influenzae, enteric gram-negative rods and Streptococcus agalactiae implicated.¹ Additionally, Mycoplasma genitalium, cytomegalovirus (CMV), and Ureaplasma urealyticum have been associated with some cases of PID.¹ Ascending infection occurs when microbes spread along mucosal surfaces from the vagina and cervix through to the endometrial cavity, fallopian tubes and into the abdominal cavity. During post-infection repair processes, ingrowing fibroblasts cause scarring and tubal function impairment that may cause irreversible infertility.³ While women may tolerate a range of symptoms for some months before seeking care, tubal infection and scarring can occur early, with inflammation occurring within hours for gonorrhoea and days for chlamydia.³

Risk factors for PID:

• young sexually active women;
• multiple partners or partner change;
• unprotected sex; and
• previous PID.⁴

Diagnosis

PID symptoms can be mild and it can be easy to overlook infection as a cause of pelvic pain, menstrual change or pain with intercourse.

Women may attribute fluctuating symptoms to gastrointestinal difficulties, a change in hormonal contraception or the particular dynamics of intercourse with a new partner. Certainty of diagnosis can be frustrating for both patient and clinician: clinical symptoms and signs of PID lack sensitivity and specificity1, and diagnostic rates for PID differ significantly between clinicians in specialist settings caring for similarly at-risk patients.⁵

Prompt antibiotic treatment is safe and effective. Given the risk of long-term sequelae, Australian and international clinical guidelines suggest clinicians maintain a high index of suspicion for diagnosis of PID, and a low threshold for treatment.^1,2,6

‘A diagnosis of PID, and empirical antibiotic treatment, should be considered and usually offered in any young (under 25) sexually active woman who has recent onset, bilateral lower abdominal pain associated with local tenderness on bimanual vaginal examination, in whom pregnancy has been excluded.’⁶

PID symptoms can vary significantly in both presence and severity. Key symptoms are:

• lower abdominal/pelvic pain;
• abnormal vaginal discharge;
• deep dyspareunia; and
• menstrual changes, including irregular bleeding, postcoital bleeding and increasing dysmenorrhoea/menhorrhagia.^1,3,6

Addressing each of these manifestations, including enquiry about change over recent months, can help a woman describe her symptoms and assist in diagnosis. While the absence of one or more of these symptoms does not preclude diagnosis, the accurate documentation of symptoms before treatment provides the basis for review of treatment efficacy.

Signs of PID include the following:

• tenderness to palpation in the lower abdominal or pelvic region;
• abnormal cervical discharge;
• uterine, adnexal or cervical motion tenderness on bimanual examination; and
• fever >38°C in acute or severe PID.^1,3,6

Again, the absence of one or more of these signs should not preclude a presumptive diagnosis of PID. If bimanual examination is declined, or is otherwise inappropriate, it is worth revisiting the history and in the absence of a plausible alternative diagnosis; a presumptive diagnosis of PID may still be warranted.

Perihepatitis, or Fitz-Hugh-Curtis syndrome, may complicate PID and presents as sharp, pleuritic right upper quadrant pain, with reproductive tract symptoms of varying severity.⁷

Laparoscopy is the ‘gold standard’ for diagnosing PID; however, endometritis and subtle fallopian tube inflammation may be missed during this procedure, and high cost, limited availability and impracticality of laparoscopy in mild cases of PID means that diagnosis is almost always based on history and clinical examination findings.¹ 

Given the role of sexually transmitted organisms in PID pathogenesis, young women presenting with a parent or carer benefit from the opportunity for private discussion of sexual activity at some point in their consultation; noting also that there are case reports of PID in young women who are not yet sexually active.⁸

Investigations

Pregnancy should be excluded in all women of reproductive age with lower pelvic pain.⁶ On speculum examination, endocervical swabs should be collected for chlamydia and gonorrhoea PCR (multiplex PCR according to local protocols) as well as microscopy, culture and sensitivity.⁶ Consider concurrent syphilis and HIV testing.

Is there a role for imaging at the time of PID diagnosis? Transvaginal ultrasound has been shown to detect dilated tubes, thickening of the tubal wall and tubal fluid in mild PID, and it may be useful to assess the extent of damage in severe PID, when tuboovarian abscess, enlarged fallopian tubes and ovaries and excess fluid are present.³ Transvaginal power Doppler sonography can detect all of the above, as well as hyperemia in women with acute PID, which is largely absent in women who do not have acute inflammation.³ Although a useful tool to support diagnosis, empiric treatment of PID should not be delayed pending ultrasound nor withheld in view of normal ultrasound findings.

However, early pelvic ultrasound can be helpful if symptoms are atypical of PID and/or if there is right upper quadrant pain suggestive of Fitz-Hugh Curtis syndrome. Pelvic ultrasound is also indicated to evaluate symptoms that persist after PID treatment.

Differential diagnosis

The differential diagnosis of pelvic pain in women of reproductive age can include:

• ectopic pregnancy;
• appendicitis (usually associated with migration of pain, unilateral abdominal tenderness, and nausea and vomiting⁹);
• endometriosis;
• ovarian cyst;
• urinary tract infection; and
• functional pain.⁴

Management

Prompt treatment is necessary to decrease the risk of long-term complications, which include ectopic pregnancy, infertility and chronic pelvic pain.² Broad-spectrum antibiotic treatment is necessary to cover sexually transmitted infections and aerobic and anaerobic bacteria.

Outpatient treatment of PID is appropriate for women with mild to moderate PID.⁶ Admission should be considered when a surgical emergency cannot be excluded, in clinically severe disease and when symptoms worsen despite treatment.⁶

Current Australian recommendations for treatment for mild to moderate sexually acquired PID are:

• metronidazole 400mg orally, twice a day for 14 daysplus
• azithromycin 1g orally as a single dose plus either
• azithromycin 1g as a single dose one week lateror
• doxycycline 100mg orally, twice a day for 14 days and, in patients in whom gonorrhoea is potentially a causative organism,
• ceftriaxone 500mg IM or IV, as a single dose.¹⁰

If a woman has an intrauterine device (IUD) in situ, PID treatment should still follow recommended regimes. Removal of the IUD needs to be balanced against the risk of pregnancy. Removal may improve short-term outcomes and should be considered if there is no clinical response within 72 hours of commencing treatment or if the woman requests removal.¹¹

Patient information

Two weeks of oral antibiotic treatment can be challenging. An understanding of the rationale for both the diagnosis of PID and prolonged broad-spectrum antibiotic treatment can ease concern and support adherence.

Patient information should also include:

• treatment side effects;
• recommendation not to have sex until treatment is completed
  and partner(s) have also been treated;
• possibility of long-term complications of PID; and
• episodes of PID increase the risk of infertility, can be reduced by concurrent treatment of current partner(s), condom use with new partners and partner testing prior to unprotected sex.⁶

Contact tracing and partner treatment

All current and recent male sexual partners of women with suspected sexually acquired PID should be empirically treated with azithromycin 1g orally for chlamydia infection, with treatment for gonorrhoea dependant on regional prevalence, regardless of whether they are symptomatic or not.^3,12

Follow up

Early review at 72 hours is recommended for moderate to severe clinical presentation; clinical symptoms and signs should show substantial improvement. Persistent symptoms suggest the need for further investigation, parenteral therapy or surgical intervention.⁶

Review at two-to-four weeks is useful to assess symptom resolution, check partners have been treated, repeat pregnancy testing if needed, and to discuss again PID and reduction of risk of further episodes.⁶ A diagnosis of PID can be distressing and questions about the impact of infection on fertility can also be addressed.

If chlamydia or gonorrhoea infection is confirmed, further testing is recommended at three months to exclude reinfection.¹

Summary

Clinical assessment remains the cornerstone of PID diagnosis. Maintaining a high index of suspicion for infection as the cause of pelvic pain and associated symptoms in women with risk factors supports early treatment. Scheduled follow up provides a safety net to ensure further investigation of persistent symptoms and signs; just as importantly, follow up provides an opportunity to check patient understanding, answer questions and to discuss prevention of further episodes of PID.