Infectious Disease Book

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Chlamydia trachomatisAka: Chlamydia

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  1. Epidemiology: Very Prevalent
    1. Asymptomatic teenage female test positive: 5-10%
    2. Sexually active persons: 10%
    3. Chlamydia 6 to 10 times more common than Gonorrhea
    4. Incidence: 3-5 million cases/year
  2. Cause
    1. Chlamydia trachomatis (obligate intracellular organism)
  3. Symptoms: Women
    1. General
      1. Untreated infections may persist for months
      2. Usually asymptomatic
    2. Urethritis: Dysuria sterile-pyuria syndrome
      1. Persistent Dysuria and pyuria
      2. No frequency or urgency
      3. Negative Urine Culture
    3. Other symptoms
      1. Post-coital bleeding (Friable Cervix)
      2. Vaginal Discharge (no odor, mucus)
      3. Pelvic Pain (consider Pelvic Inflammatory Disease)
  4. Symptoms: Men
    1. Often symptomatic
    2. Urethritis
      1. Mild to moderate, clear or white urethral discharge
  5. Complications
    1. Pelvic Inflammatory Disease
    2. Infertility
    3. Preterm Labor
    4. Perinatal transmission to newborn
      1. Chlamydia Conjunctivitis
      2. Neonatal Chlamydia Pneumonia
    5. Epididymitis (men)
    6. Reiter's Syndrome (more common in men)
      1. Arthritis
      2. Conjunctivitis
      3. Urethritis
  6. Screening Indications
    1. Women
      1. Screen all women with mucopurulent Cervicitis
      2. Screen all sexually active women age 25 and younger
      3. Screen all pregnant women
    2. Men
      1. Urethritis in men (especially age <35 years)
  7. Labs: Differential Diagnosis
    1. Wet Prep
    2. Potassium Hydroxide exam
    3. CDC recommends concurrent Gonorrhea testing
    4. Consider other STD Testing (HIV, Hepatitis B, RPR)
  8. Labs: Diagnosis
    1. Chlamydia Culture
      1. Indication: required for medicolegal cases only
      2. Sensitivity: 60-80%
      3. Specificity: 100%
    2. Polymerase/Lipase chain reaction
      1. Sensitivity
        1. Cervix: >90%
        2. Male urethra: >95%
        3. Urine male and female: >90%
      2. Specificity: 94 to 99.5%
    3. Urinalysis Leukocyte Esterase test (men)
      1. High Test Sensitivity for Chlamydia
        1. Sensitivity for Chlamydia Infection: 46-100%
      2. Positive test: perform urine Chlamydia Antigen
    4. Gram Stain findings suggestive of Chlamydia
      1. Urethral discharge: WBCs >5/hpf (no Gonorrhea seen)
      2. First void urine: WBCs >10/hpf
    5. Everted inner lid swab for Chlamydia PCR (neonates)
  9. Management: Antibiotics
    1. First Choice
      1. Azithromycin 1 gram PO for 1 dose
      2. Doxycycline 100 mg PO bid for 7 days
    2. Alternatives
      1. Ofloxacin 300 mg PO bid for 7 days
      2. Erythromycin 500 mg PO qid for 7 days
      3. Erythromycin Ethylsuccinate (EES)
        1. Dose: 800 mg PO qid for 7 days
      4. Amoxicillin 500 mg PO tid for 7 days
      5. Clindamycin 450 mg PO qid for 14 days
    3. Persistant or recurrent urethritis despite treatment
      1. Metronidazole 2 grams orally for 1 dose and
      2. Erythromycin base 500 mg orally twice daily x7 days
    4. Pregnancy
      1. Azithromycin 1 gram PO as single dose
      2. Erythromycin OR EES as above for 7 days
      3. Amoxicillin 500 PO tid x7 days (Only 50% effective)
    5. Neonates (Conjunctivitis or Chlamydia Pneumonia)
      1. Erythromycin base 50 mg/kg PO divided qid for 14 days
      2. Second course needed in 20% of cases
  10. Management: General
    1. Refer all sexual contacts for treatment
    2. No intercourse for 7 days
    3. Rescreen for Chlamydia infection in 3-4 months
    4. Indications to retest after antibiotic completion
      1. Persistent symptoms
      2. Pregnancy
  11. Prevention: Annual screening guidelines
    1. All sexually active women under age 25 years
    2. All sexually active women with STD risks
  12. References
    1. (1998) MMWR Morb Mortal Wkly Rep 47:1
    2. (2002) MMWR Recomm Rep 51:1
    3. Miller (2006) Am Fam Physician 73:1411

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