Describe the causes, clinical features, diagnosis, management and complications of pelvic Inflammatory Disease.

Low threshold for treatment — delay causes tubal damage.

Definition

Pelvic inflammatory disease (PID) is an acute infection and inflammation of the upper female genital tract — the endometrium (endometritis), fallopian tubes (salpingitis), ovaries (oophoritis) and pelvic peritoneum — usually resulting from ascending infection from the lower genital tract.

PID - Ascending Infection

Causative Organisms

Mostly sexually transmitted — Chlamydia trachomatis and Neisseria gonorrhoeae — usually becoming polymicrobial with anaerobes, Gram-negative bacteria and genital mycoplasmas; tuberculosis causes chronic PID.

Routes of Spread

Infection usually ascends from the cervix and vagina along the mucosa to the endometrium, tubes and ovaries, and onto the pelvic peritoneum; less often it spreads by the lymphatics (after delivery/abortion or with an IUCD) or by the blood-stream (tuberculosis).

Risk Factors

Multiple sexual partners and young age, a previous episode of PID, recent IUCD insertion or intra-uterine instrumentation (D&C, MTP, HSG), and the post-partum/post-abortal state.

Acute and Chronic PID

Acute PID presents with the florid features below; inadequately-treated infection leads to chronic PID — persistent pelvic pain, dyspareunia, menstrual disturbance, a hydrosalpinx/chronic tubo-ovarian mass and dense pelvic adhesions causing infertility.

Clinical Features

Lower abdominal/pelvic pain, fever, abnormal vaginal discharge, deep dyspareunia and abnormal bleeding; signs include lower-abdominal tenderness, cervical motion (excitation) tenderness and adnexal tenderness. Fitz-Hugh-Curtis syndrome (perihepatitis) causes right-upper-quadrant pain.

Investigations

• Endocervical/vaginal swabs and NAAT for chlamydia and gonorrhoea; a pregnancy test (to exclude ectopic).
• White-cell count, CRP/ESR; ultrasound/TVS to detect a tubo-ovarian abscess or pyosalpinx.
• Laparoscopy — the gold standard in doubtful or severe cases.

Management

• Broad-spectrum antibiotics covering chlamydia, gonococcus and anaerobes (e.g. Ceftriaxone + doxycycline + metronidazole), started empirically.
• Outpatient treatment for mild cases; admit for severe illness, pregnancy, a tubo-ovarian abscess, failure of oral therapy, or an uncertain diagnosis (then intravenous antibiotics).
• Treat the partner and advise abstinence; consider removing an IUCD if there is no response; drain a tubo-ovarian abscess if it does not resolve.

WHY PID Matters Long After the Infection Is Cured

The importance of pelvic inflammatory disease lies less in the acute illness than in why it leaves permanent damage even after the infection has been eradicated. The infection ascends from the cervix to the tubes, where the inflammation destroys the delicate ciliated epithelium and the fine architecture of the tubal lumen — and this tissue does not regenerate. The tube heals instead by fibrosis and scarring: the fimbriae become clubbed and adherent, the lumen becomes narrowed or blocked, and peritubal adhesions distort its relationship to the ovary. Three lifelong consequences follow. First, infertility — the tubes can no longer pick up or transport the ovum, and the risk rises steeply with each episode (roughly 12% after one attack, 25% after two, 50% after three). Second, ectopic pregnancy — a partially damaged tube may allow sperm through but cannot transport the fertilised ovum onward, so it implants where it lies (a six- to tenfold increased risk). Third, chronic pelvic pain and dyspareunia from adhesions. Understanding that the damage is structural and irreversible explains why the prompt, adequate treatment of even mild PID — and its prevention — matters so much, and why treatment must never wait for culture results.

WHY Treatment Is Empirical, Broad and Immediate

A crucial clinical principle is why PID is treated on suspicion, with broad-spectrum antibiotics, before any organism is identified. Three facts drive this. First, the diagnosis is clinical and imprecise: the classic signs (lower abdominal pain, cervical excitation and adnexal tenderness, with fever and discharge) are neither sensitive nor specific, and waiting for certainty means waiting while the tubes are destroyed. Second, the damage is time-dependent and irreversible — every hour of untreated inflammation adds to the scarring — so the cost of treating a woman who turns out not to have PID (a course of antibiotics) is trivially small compared with the cost of missing one (lifelong infertility). Hence the rule: a low threshold to treat. Third, the infection is characteristically polymicrobial — Chlamydia trachomatis and Neisseria gonorrhoeae ascending from the cervix, together with anaerobes and other vaginal flora — so no single agent will cover it; treatment must therefore be a combination (typically ceftriaxone plus doxycycline plus metronidazole). Finally, and often forgotten, the sexual partner must be treated simultaneously, or the woman is simply reinfected.

• PID = ascending infection of the upper genital tract (endometritis, salpingitis, tubo-ovarian abscess, peritonitis); usually polymicrobial — Chlamydia and gonococcus with anaerobes.
• Clinical: lower abdominal pain, cervical excitation and adnexal tenderness, fever, discharge; Fitz-Hugh-Curtis syndrome (perihepatitis) gives right upper quadrant pain.
• Treat empirically on suspicion — do not wait for cultures; the tubal damage is time-dependent and irreversible.
• Antibiotics: ceftriaxone + doxycycline + metronidazole; treat the partner too, or reinfection follows.
• Sequelae: infertility (risk rises with each episode), a 6–10-fold increase in ectopic pregnancy, chronic pelvic pain and dyspareunia.