II. Epidemiology

  1. Most common Sexually Transmitted Infection in the United States
  2. Incidence: 2.8 million cases/year in U.S. as of 2010
  3. Asymptomatic teenage female test positive: 5-10%
  4. Sexually active persons: 10%
  5. Chlamydia infection is 6 to 10 times more common than Gonorrhea

III. Cause

  1. Chlamydia trachomatis (obligate intracellular organism)

IV. 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. Cervicitis
      1. Presents as post-coital bleeding (Friable Cervix)
      2. Mucopurulent discharge from Cervix
    2. Vaginitis
      1. Vaginal Discharge (no odor, mucus)
    3. Pelvic Pain
      1. Consider Pelvic Inflammatory Disease

V. Symptoms: Men

  1. Asymptomatic in up to 98% of men
  2. Epididymitis
  3. Urethritis
    1. Mild to moderate, clear or white Urethral discharge

VI. Labs: 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)

VII. Labs: Differential Diagnosis

  1. Vaginitis evaluation
    1. Wet Prep
    2. Potassium Hydroxide exam
  2. Sexually Transmitted Disease testing
    1. Gonorrhea (CDC recommends)
    2. STD Blood Testing (strongly consider)
      1. HIV Test (recommended in all patients with Chlamydia)
      2. Hepatitis B (HepBsAg)
      3. Syphilis (RPR)

VIII. Labs: Diagnosis

  1. Chlamydia Polymerase Chain Reaction DNA Probe (preferred)
    1. Same swab can be sent for Gonorrhea DNA testing
      1. Swab source can be endocervical, Urethral, vaginal, pharyngeal or rectal
      2. Dirty urine (no cleansing prior) can be tested as well (first morning void is preferred)
    2. Test Sensitivity
      1. Cervix: >90%
      2. Male Urethra: >95%
      3. Urine male and female: >90%
    3. Test Specificity: 94 to 99.5%
    4. Avoid Chlamydia Rapid Point-Of-Care Test (Test Sensitivity <58%)
  2. Chlamydia Culture
    1. Indication: required for medicolegal cases only
    2. Test Sensitivity: 60-80%
    3. Test Specificity: 100%
  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)

X. Management: General

  1. Refer all sexual contacts within prior 60 days for treatment
  2. No intercourse until both partners have been fully treated and for 7 days after
  3. Strongly consider concurrent empiric treatment for Gonorrhea (especially in Emergency Department)
    1. Ceftriaxone 500 mg IM/IV for 1 dose (1 gram IM/IV if weight > 150 kg, dose increased in 2020) AND
    2. Azithromycin or Doxycyline (see below)
    3. At minimum, test for Gonorrhea
  4. Rescreen for new Chlamydia infection in 3-4 months (re-infection is common)
    1. Test of cure is recommended only in pregnancy and if symptoms persist
      1. Re-test all pregnant women 3-4 weeks after treatment
  5. Consider other causes of STI in refractory symptoms despite treatment
    1. See differential diagnosis as above
    2. Mycoplasma Genitalium is responsible for 30% of Non-Gonococcal Urethritis

XI. Management: Antibiotics

  1. See Chlamydia Conjunctivitis (includes Trachoma, Inclusion Conjunctivitis)
  2. See Lymphogranuloma venereum
  3. First-line agents for uncomplicated genitourinary infections in non-pregnant patients
    1. Azithromycin 1 gram orally for 1 dose OR
    2. Doxycycline 100 mg orally twice daily for 7 days (preferred)
  4. Alternative agents for uncomplicated genitourinary infections in non-pregnant patients
    1. Ofloxacin 300 mg orally twice daily (or 600 mg once daily) for 7 days or
    2. Levofloxacin (Levaquin) 500 mg orally daily for 7 days or
    3. Erythromycin 500 mg orally four times daily for 7 days or
    4. Erythromycin EthylSuccinate (EES) 800 mg orally four times daily for 7 days or
  5. Pregnancy
    1. Azithromycin 1 gram orally once as single dose or
    2. Erythromycin OR EES as above for 7 days or
    3. Amoxicillin 500 mg orally three times daily for 7 days (Only 50% effective)
  6. Neonates (Neonatal Conjunctivitis or Chlamydia Pneumonia)
    1. Erythromycin Base or EES 50 mg/kg orally divided four times daily for 14 days
    2. Second course needed in 20% of cases
  7. 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
  8. Chronic Reactive Arthritis (Reiter Syndrome)
    1. Rifampin 300 mg once daily for 6 months AND
    2. One of the following:
      1. Doxycycline 100 mg orally twice daily for 6 months or
      2. Azithromycin 500 mg orally daily for 5 days and then 500 mg twice weekly for 6 months

XII. 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
  7. Fitz-Hugh-Curtis Syndrome (rare)
    1. Perihepatitis Syndrome presents with right upper quadrant pain
  8. Extra-genital infections
    1. Chlamydia Conjunctivitis
    2. Pharyngitis (oral sex)
      1. Gonorrhea is more common orally
    3. Anal infection (Receptive anal intercourse)
      1. Rectal Chlamydia may be resistant to Azithromycin (Doxycycline is preferred)

XIII. Prevention: Annual screening guidelines

  1. All sexually active women under age 25 years
  2. All sexually active women with STD risks
  3. Consider in sexually active men under age 25 years or with STD risks

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