Epidemiology

Globally, accurately determining the true burden of PID is challenging due to the high proportion of asymptomatic or misdiagnosed cases. In sub-Saharan Africa, PID is a significant yet under-recognized public health concern, contributing to infertility, ectopic pregnancy, chronic pelvic pain, and adverse pregnancy outcomes. Recent global analyses from 1990 to 2019 indicate that Western and Central sub-Saharan Africa have some of the highest age-standardized prevalence rates (ASPR) of PID among reproductive-aged women. For example, in 2019, Western sub-Saharan Africa had an ASPR of approximately 116 per 100,000 women. Chlamydia trachomatis is a key driver of PID, with a pooled prevalence of about 7.8% among reproductive-age women in sub-Saharan Africa.

Pathology, Pathogenesis, and Microbiology

PID develops when microorganisms ascend from the lower to the upper genital tract. Acute, clinically diagnosed PID is generally caused by spontaneous ascension of microbes from the cervix or vagina to the endometrium, fallopian tubes, and adjacent structures.

• Sexually transmitted pathogens: Chlamydia trachomatis and Neisseria gonorrhoeae are classical agents, but now account for fewer than half of PID cases.
• Emerging pathogens: Mycoplasma genitalium is increasingly recognized for its association with cervicitis, endometritis, and salpingitis, though its full role is still being studied.
• Polymicrobial infections: Anaerobes and facultative bacteria linked to bacterial vaginosis (such as Gardnerella vaginalis, Atopobium vaginae, Mobiluncus, and Prevotella) are also implicated. Enteric organisms like E. coli and respiratory pathogens like Haemophilus influenzae may sometimes be involved.

The inflammation caused by PID leads to fibrinous or suppurative damage along the fallopian tubes, resulting in scarring, adhesions, and loss of ciliated cells. These structural changes are responsible for complications such as infertility, ectopic pregnancy, and chronic pelvic pain.

Risk Factors

• Sexual behavior: Having multiple sexual partners, new partners, or a history of sexually transmitted infections increases risk.
• Age: Women under 25 years are at greater risk, partly due to biological susceptibility and cervical ectopy.
• Contraception: Use of intrauterine devices (IUDs) is associated with a transiently increased risk in the first month after insertion, but the risk is low subsequently if STI screening is done.
• Reproductive factors: Early onset of sexual activity and douching have been associated with increased risk, though evidence for douching is inconclusive.
• Medical procedures: Gynecological procedures that disrupt the cervical barrier, such as curettage, endometrial biopsy, or hysteroscopy, can facilitate ascending infections.
• Immune status: Women living with HIV or with genetic factors affecting innate immunity may be more susceptible.

Symptoms and Clinical Findings

The most common symptom of PID is lower abdominal or pelvic pain, usually bilateral and worsened by movement or intercourse. Other symptoms include abnormal vaginal discharge, intermenstrual or postcoital bleeding, dyspareunia, dysuria, and occasionally fever or nausea.

On pelvic examination, diagnostic hallmarks include cervical motion tenderness, uterine tenderness, or adnexal tenderness. Adnexal tenderness is considered the most sensitive physical examination finding. Mucopurulent cervical discharge and cervical friability may also be noted.

Differential Diagnosis

Diagnosing PID can be challenging due to symptom overlapping with other gynecologic and surgical emergencies. Ectopic pregnancy, appendicitis, and ovarian torsion must always be considered. Consequently, a pregnancy test is mandatory for every woman of reproductive age presenting with abdominal pain. Other differential diagnoses include urinary tract infection, endometriosis, and adnexal tumors.

Investigations

No single test can confirm PID, so clinicians should maintain a high index of suspicion in sexually active women of reproductive age presenting with lower abdominal pain. Nucleic acid amplification testing (NAAT) for Chlamydia trachomatis and Neisseria gonorrhoeae is recommended where available, along with microscopy of vaginal secretions for leukocytes or bacterial vaginosis. Imaging techniques such as transvaginal ultrasonography or MRI can reveal fluid-filled or thickened fallopian tubes, tubal hyperemia, or tubo-ovarian abscesses. Laparoscopy with culture of endometrial aspirate remains the gold standard for diagnosis but is rarely used in routine practice due to its invasiveness.

Treatment

Prompt empiric therapy is essential, as the risk of overtreatment with antibiotics is less than the risk of long-term sequelae from untreated PID. Thus, CDC and other guidelines recommend empirical treatment once samples are collected. Broad-spectrum coverage of likely pathogens is necessary. Most women can be managed as outpatients with a first-line regimen of ceftriaxone 500 mg intramuscularly as a single dose, plus doxycycline 100 mg orally twice daily for 14 days, combined with metronidazole 500 mg orally twice daily for 14 days. Most patients are successfully treated with this approach.

Oral quinolones are not indicated for PID treatment except where there is a low prevalence of gonorrhea. Oral moxifloxacin may be used for PID not responding to standard treatment and potentially due to Mycoplasma genitalium. Amoxiclav is not indicated for PID. Other treatment aspects include contact tracing, treating all current sexual contacts or sexual partners within the last 60 days, advising abstinence during treatment, ensuring antibiotics are administered for up to 14 days, counseling for compliance, and promoting mutual fidelity.

Hospital admission is required for severe illness, pregnancy, inability to tolerate oral medications, or suspected tubo-ovarian abscess. Inpatient regimens typically consist of parenteral third-generation cephalosporins with doxycycline, with or without metronidazole, with conversion to oral therapy within 24 hours of symptom improvement.

Follow-Up

Clinical improvement is expected within 72 hours. If symptoms persist, hospitalization or laparoscopy should be considered. Women treated for chlamydia or gonorrhea should be retested after three months to check for reinfection.

Prevention and Control

Preventing and promptly treating sexually transmitted infections is the most effective strategy to reduce PID incidence. Public health measures include counseling for sexual abstinence, screening sexually active women under 25, consistent condom use, prompt treatment of partners, and mutual fidelity. These interventions reduce PID recurrence and long-term complications such as infertility and chronic pelvic pain.

Pelvic inflammatory disease remains a major cause of infertility, chronic pelvic pain, and ectopic pregnancy globally. In sub-Saharan Africa, PID is often diagnosed clinically due to limited resources. The nonspecific nature of symptoms requires clinicians to maintain a low threshold for diagnosis and begin empiric treatment promptly. Early recognition, broad-spectrum antibiotics, partner treatment, and preventive measures such as STI screening and condom use are essential in reducing the burden of PID.

Reflection

In clinical practice, it is evident that many physicians outside gynecology are reluctant to perform speculum examinations, although this step is crucial for diagnosing PID and identifying other possible conditions. For some women, this examination may be their only encounter with a dedicated healthcare provider. Additionally, some practitioners treat PID for only 5–7 days or use Augmentin, which is not recommended. Adhering to established guidelines and maintaining a high level of suspicion can ensure timely treatment and help preserve fertility. Raising awareness among patients and healthcare workers, especially in resource-limited settings, is vital for improving outcomes.