Chlamydia — Non-gonococcal

Sexually transmitted infection caused by the bacterium Chlamydia trachomatis

Aetiology

Chlamydia trachomatis is:
  • Gram-negative–like (but lacks peptidoglycan)
  • Obligate intracellular
  • Cannot synthesize its own ATP (“energy parasite”)
Chlamydia has a unique biphasic life cycle:
Form
Characteristics
Role
Elementary body (EB)
Infectious, extracellular
Transmission
Reticulate body (RB)
Non-infectious, intracellular
Replication
This intracellular lifecycle explains:
  • Chronicity
  • Subclinical infection
  • Immune evasion

Pathophysiology

  1. Attachment of EB to columnar epithelial cells
  1. Endocytosis into host cell
  1. Transformation into RB
  1. Intracellular replication
  1. Host inflammatory response
  1. Cell rupture → tissue damage

Key Pathophysiologic Mechanisms

  • Cell-mediated immunity
  • Chronic inflammation → fibrosis
  • Ascending infection in genital tract

Clinical presentation

Women

  • 70-80% of women asymptomatic
Symptoms
  • Dysuria
  • Abnormal vaginal discharge
  • Intermenstrual or postcoital bleeding
  • Deep dyspareunia
  • Lower abdominal pain
Signs
  • Cervicitis +/- contact bleeding
  • Mucopurulent endocervical discharge
  • Pelvic tenderness
  • Cervical excitation

Men

  • 50% of men are asymptomatic
Symptoms
  • Urethritis
    • Dysuria
    • Urethral discharge
  • Epididymo-orchitis
    • Testicular pain
Signs
  • Epididymal tenderness
  • Mucoid or clear urethral discharge

Investigations

  • NAAT
    • Women: vulvo-vaginal swab (first choice), endocervical swab or first catch urine sample
    • Men: first catch urine sample (first choice) or urethral swab

Management

  • First line - doxycycline 100mg BID for 1 week
  • Second line - azithromycin 1G SD followed by 500mg daily for 2 days
  • Contact tracing

Complications

  • PID, ectopic pregnancy, tubal damage
  • Reactive arthritis
  • Conjunctivitis
  • Fitz Hugh-Curtis