Sexually Transmitted Infections

Includes parts of CUAJ 2019 Penile Lesions Review

Epidemiology

• Most common bacterial STI in the US (descending order):
  1. Chlamydia
  2. Gonorrhea
• Risk factors:
  • Number of lifetime sex partners
  • Unprotected sex without use of a condom
  • Risky sex partners
  • Effect of alcohol or drugs on sexual decision making
• Centers for Disease Control and Prevention Screening Recommendations
  • Females
    • Annual chlamydia screening for all sexually active women age ≤ 25, as well as for women with risk factors such as new or multiple sex partners.
    • Annual gonorrhea screening for at-risk sexually active women, including women with new or multiple sex partners, or women who are living in areas with high rates of disease.
    • Syphilis, HIV, and chlamydia screening for all pregnant women, and gonorrhea screening for at-risk pregnant women starting early in pregnancy, with repeat testing as needed.
  • Males
    • At least once-per-year screening for syphilis, chlamydia, gonorrhea, and HIV for all sexually active gay, bisexual, and other men who have sex with men (MSM).
    • Men who have multiple or anonymous partners should be screened more frequently for STIs, at 3- to 6-month intervals. More frequent screening is also recommended for MSM who use illicit drugs, particularly methamphetamine, or whose sex partners use them.
• Reportable diseases in every US state (5):
  1. Chlamydia
  2. Gonorrhea
  3. Syphilis
  4. Chancroid
  5. HIV/AIDS

Urethritis

• Urethritis, or urethral inflammation, can be the result of STIs.
• Classified as gonococcal vs. non-gonococcal
  • Gonococcal Urethritis
    • Caused by Neisseria gonorrhoeae, a gram-negative diplococcus
      • An oxidase positive culture on Thayer-Martin medium is diagnostic of Neisseria gonorrhea
    • Incubation period: 3-14 days
  • Non-gonococcal urethritis (NGU)
    • Caused by organisms other than Neisseria gonorrhoeae
      • Chlamydia trachomatis accounts for 15-40% of cases of NGU, with less common causes including Mycoplasma genitalium, Trichomonas vaginalis, adenoviruses, and herpes simplex virus type 1 (HSV-1)
    • Chlamydia
      • Gram-negative
      • Incubation period: 3-14 days (same as gonorrhea)
    • Mycoplasma genitalium
      • Mycoplasmas lack a cell wall and cannot be Gram stained.
      • Can become intracellular, which can establish a chronic infection and aid in avoidance of both immune response and antibiotics
      • Risk factors in men are young age, sexual intercourse in the past month, and a sex partner with a recent history of STI diagnosis or treatment
    • Ureaplasma
      • The evidence for Ureaplasma as a causative agent in NGU is conflicting
    • Trichomonas vaginalis
      • Flagellated parasite that exclusively infects the urinary tract
      • Common vaginal pathogen but also can cause urethritis in men
• Natural History
  • Gonorrhea
    • Complications in females: pelvic inflammatory disease (PID), tubal scarring, infertility, ectopic pregnancy, and chronic pelvic pain
    • Can increase the risk of contracting and transmitting HIV
    • Disseminated gonorrhea is rare today but can produce arthritis, dermatitis, meningitis, and endocarditis.
  • Chlamydia
    • The major health risk of untreated chlamydial infections in men is transmission to their female partners resulting in PID
    • Complications in males include epididymitis and Reiter syndrome (conjunctivitis, urethritis, and reactive arthritis)
    • Ascending chlamydial infection in females can result in scarring of the fallopian tubes, PID, risk for ectopic pregnancy, pelvic pain, and infertility
• Diagnosis and Evaluation
  • History and Physical Exam
    • History
      • Symptoms of urethritis include urethral discharge, pruritus, and dysuria
      • Gonorrhea
        • Campbell’s: Men will usually have symptoms that cause them to seek treatment soon enough to prevent transmission to others. This could include urethritis, epididymitis, proctitis or prostatitis.
          • CUAJ Penile Lesions Review 2019: In men, it is most often asymptomatic, but symptoms can include dysuria or mucopurulent discharge. [but multiple sources including Public Health Ontario and UptoDate say gonorrhea is symptomatic in most men)
        • Women are frequently asymptomatic.
      • Chlamydia
        • Symptoms in males include dysuria, urethral discharge, and epididymitis
          • [UptoDate] up to 42% of men with NGU are asymptomatic
        • Up to 75% of women with chlamydial infection can be asymptomatic.
      • Mycoplasma genitalium
        • Most infected patients are symptomatic, but ≈25% may have asymptomatic urethral infection
    • Labs
      • Nucleic acid amplification tests (NAATs) performed on urine
        • Can be used to look for gonorrhoeae and chlamydia
          • All patients should be tested for both gonorrhea and chlamydia, given the high association of co-infection.
        • Culture and hybridization tests that require urethral swab specimens are available. However, NAATs are preferred because of their higher sensitivity, and urethral swabs are no longer recommended for evaluation of urethritis
        • Culture for Mycoplasma genitalium is very difficult, and the diagnosis is made by NAATs or polymerase chain reaction (PCR)
        • NAAT has replaced wet mounts and culture for diagnosis of trichomonas vaginalis
• Management
  • Antibiotics
    • Current treatment of uncomplicated gonococcal infections involves ceftriaxone 250 mg IM single dose with
      • Azithromycin 1 gm PO x single dose or
      • Doxycycline 100 mg PO BID x 7 days
    • Dual therapy is required for both N. gonorrhoeae and chlamydia because of the high rate of coinfection
  • All persons with gonorrhea should be tested for other STIs including syphilis and HIV