Infectious Disease · Sexually Transmitted Infections
The facts most likely to be tested
Chlamydia trachomatis is the most common bacterial sexually transmitted infection in the United States and is frequently asymptomatic in both men and women.
Nucleic acid amplification testing (NAAT) is the gold standard diagnostic test for urogenital chlamydial infections using first-catch urine or vaginal swabs.
Doxycycline (100 mg twice daily for 7 days) is the first-line treatment for uncomplicated urogenital chlamydia in non-pregnant adults.
Azithromycin (1 g orally in a single dose) is the preferred treatment for chlamydia in pregnant patients to avoid the teratogenic effects of tetracyclines.
Lymphogranuloma venereum (LGV), caused by serovars L1-L3, presents with a painless genital ulcer followed by painful, matted inguinal lymphadenopathy known as buboes.
Fitz-Hugh-Curtis syndrome is a rare complication of pelvic inflammatory disease (PID) characterized by perihepatitis and 'violin-string' adhesions on the liver capsule.
Neonatal conjunctivitis caused by Chlamydia trachomatis typically presents 5-14 days after birth and is treated with systemic oral erythromycin.
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A 22-year-old female presents to the clinic for a routine check-up. She reports no symptoms but mentions she has a new sexual partner and does not consistently use barrier protection. On physical exam, there is no cervical motion tenderness or adnexal masses. A cervical swab is collected for NAAT. Two days later, the laboratory reports a positive result for Chlamydia trachomatis.
What is the most appropriate management for this patient's sexual partner?
Expedited partner therapy (EPT) or referral for presumptive treatment
This tests the requirement for partner notification and treatment to prevent reinfection, which is a core component of managing sexually transmitted infections.
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Etiology / Epidemiology
Most common bacterial STI in the US; highest incidence in sexually active adults <25 years old.
Clinical Manifestations
Often asymptomatic; classic presentation includes mucopurulent cervicitis and Fitz-Hugh-Curtis syndrome.
Diagnosis
Nucleic acid amplification test (NAAT) is the gold standard; use first-catch urine or swab.
Treatment
Doxycycline is the first-line treatment; avoid in pregnancy.
Prognosis
Untreated infection leads to pelvic inflammatory disease (PID) and infertility.
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Epidemiology & Etiology
Caused by the obligate intracellular bacterium Chlamydia trachomatis (serotypes D-K). It is the most frequently reported notifiable disease in the United States. Primary risk factors include multiple sexual partners, inconsistent condom use, and a history of prior STIs.
Pertinent Anatomy
Infection primarily targets the columnar epithelium of the endocervix, urethra, and rectum. In neonates, the organism can infect the conjunctiva and respiratory tract during passage through the birth canal.
Pathophysiology
The organism exists as an elementary body (infectious) and a reticulate body (replicative). It induces a pro-inflammatory cytokine response leading to tissue damage and scarring. Chronic inflammation results in the characteristic tubal scarring associated with ectopic pregnancy and infertility.
Clinical Manifestations
Most patients are asymptomatic, but women may present with post-coital bleeding or mucopurulent cervicitis. Men typically present with urethritis (dysuria, clear/cloudy discharge). Red flags include pelvic pain (PID) or Fitz-Hugh-Curtis syndrome (perihepatitis), which presents as RUQ pain mimicking gallbladder disease.
Diagnosis
The Nucleic acid amplification test (NAAT) is the gold standard for diagnosis due to high sensitivity and specificity. Specimens are collected via vaginal swab or first-catch urine in men. Screening is recommended annually for all sexually active women <25 years old.
Treatment
Doxycycline (100 mg BID for 7 days) is the first-line treatment for non-pregnant adults. In pregnancy, Azithromycin (1g single dose) is the preferred agent. Contraindications for Doxycycline include pregnancy due to potential for fetal tooth discoloration and bone growth inhibition.
Prognosis
Untreated infection carries a high risk of pelvic inflammatory disease (PID), which occurs in 10-15% of untreated cases. Long-term sequelae include tubal factor infertility and ectopic pregnancy. Patients must be counseled on partner notification and abstinence until treatment is completed.
Differential Diagnosis
Gonorrhea: typically presents with more purulent discharge
Trichomoniasis: presents with strawberry cervix and frothy discharge
Bacterial Vaginosis: presents with clue cells and fishy odor
Herpes Simplex: presents with painful vesicles and ulcerations
PID: presents with cervical motion tenderness