Gonorrhoea

Overview – Gonorrhoea

Gonorrhoea is a common sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. It affects both men and women, primarily targeting mucous membranes of the urethra, cervix, rectum, pharynx, and conjunctiva. Gonorrhoea presents with a wide range of symptoms or may be entirely asymptomatic, especially in women, increasing the risk of untreated complications such as pelvic inflammatory disease (PID) and infertility. Rapid diagnosis and syndromic management are crucial to control spread and avoid sequelae.

Definition

Gonorrhoea is a bacterial STI caused by Neisseria gonorrhoeae, a gram-negative diplococcus that infects mucous membranes during sexual contact or childbirth.

Aetiology

• Neisseria gonorrhoeae
• Gram-negative, aerobic diplococci
• Fastidious and virulent pathogen

Transmission

• Horizontal: Direct sexual contact (vaginal, anal, oral)
• Vertical: From mother to newborn during vaginal delivery
  • Note: Not transplacental (unlike syphilis or hepatitis B)

Morphology / Pathophysiology

Pathogenesis

• Pili: Adheres to urethral epithelium → resists flushing
• Endotoxin: Induces inflammation
• IgA Protease: Destroys host mucosal immunity

Morphology

• Macroscopic: Inflamed urethra, thick milky-white discharge
• Microscopic: Intracellular gram-negative diplococci within neutrophils on Gram stain

Clinical Features

• Onset: Symptoms appear within 1 week of exposure
• Men:
  • Acute gonococcal urethritis
  • Dysuria
  • Thick, purulent penile discharge
• Women:
  • Gonococcal cervicitis (may be asymptomatic)
  • Vaginal discharge
  • Can progress to PID (Pelvic Inflammatory Disease)

Investigations

Clinical Diagnosis

• Gonococcal urethritis:
  • Thick, milky discharge
  • Gram stain → gram-negative diplococci
• Non-gonococcal urethritis (e.g. chlamydia):
  • Thin, watery discharge
  • No organisms seen on Gram stain

Laboratory

• PCR testing:
  • 1st catch urine sample (unisex)
  • Endocervical swab (women)
  • Urethral swab (men)
  • Throat swabs (men and women)

Management

• First-line:
  • Stat dose IM Ceftriaxone
  • Plus stat dose PO Azithromycin
• Alternative:
  • Doxycycline 100 mg BD for 7 days (especially in co-infections)

Complications

• Females:
  • Pelvic Inflammatory Disease (PID) → infertility
• Males:
  • Urethral strictures
  • Epididymitis, prostatitis
• Both sexes:
  • Disseminated gonococcal infection (e.g. arthritis, endocarditis)
  • Ophthalmic infections, including neonatal conjunctivitis

Differential Diagnosis

• Chlamydia trachomatis infection (most common cause of non-gonococcal urethritis)
• Trichomoniasis
• Candidiasis
• Herpes simplex virus
• Bacterial vaginosis (in females)
• Urinary tract infection (UTI)

Summary – Gonorrhoea

Gonorrhoea is a sexually transmitted bacterial infection caused by Neisseria gonorrhoeae, which primarily affects the urethra and cervix. It presents with purulent discharge and dysuria, though many infections, especially in women, may be asymptomatic. Early diagnosis using PCR and Gram staining, followed by combination antibiotic therapy, is essential to prevent complications such as PID, infertility, and disseminated infection. For a broader context, see our Reproductive Health Overview page.