Understanding STIs: Diagnosis and Treatment Advances

Show Notes

Table of Contents

(1:49) Chlamydia 

(3:31) Gonorrhea

(4:50) PID

(6:14) Syphilis

(8:08) Neurosyphilis 

(9:13) Tertiary Syphilis

(10:06) Trichomoniasis 

(11:13) Herpes

(12:49) HIV

(14:10) PEP

(15:13) Mycoplasma Genitalium 

(18:00) Take Home Points

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Chlamydia:

• Prevalence:

• • • Most common STI.
    • High percentage of asymptomatic cases (40% to 96%).

• Presentation:

• • • Urethritis, cervicitis, pelvic inflammatory disease (PID), prostatitis, proctitis, pharyngitis, arthritis.
    • Importance of considering extra-genital sites (oral and rectal infections).

• Testing:

• • • Gold Standard: Nucleic Acid Amplification Test (NAAT) via PCR.

• Sampling Sites:

• • • • Endocervical or urethral swabs preferred over urine samples due to higher sensitivity.
      • Triple-site testing (genital, rectal, pharyngeal) recommended for comprehensive detection.

• Treatment Updates:

• • • Previous Regimen: Azithromycin 1 g orally in a single dose.
    • Current First-Line Treatment: Doxycycline 100 mg orally twice daily for 7 days.

• Alternatives:

• • • Azithromycin remains an option for patients unlikely to adhere to a 7-day regimen or for pregnant patients.
  • Note: PID treatment differs and will be discussed separately.

Gonorrhea:

• Presentation:

• • • Similar to chlamydia; can be asymptomatic.
    • Symptoms include urethritis, cervicitis, PID, prostatitis, proctitis, pharyngitis.

• Testing:

• • • Gold Standard: NAAT.

• Sampling Sites:

• • • • Endocervical swabs are more sensitive than urine samples.
      • Triple-site testing is crucial to avoid missing infections.

• Treatment Updates:

• • • Previous Regimen: Ceftriaxone 250 mg IM plus azithromycin 1 g orally.
    • Current Recommendation: Ceftriaxone 500 mg IM single dose.
      • Adjusted due to rising azithromycin resistance and updated pharmacokinetic data.

• Co-Infection Considerations:

• • High rates of chlamydia and gonorrhea co-infection (20% to 40%).
  • CDC recommends empiric treatment for chlamydia when treating gonorrhea to prevent complications like PID and infertility.

Pelvic Inflammatory Disease (PID):

• Etiology:

• • • Not solely caused by chlamydia and gonorrhea; about 50% of cases involve other pathogens like bacterial vaginosis (BV) organisms and anaerobes.

• Treatment Changes:

• Expanded Coverage Regimen:

• • • Ceftriaxone 500 mg IM once.
    • Doxycycline 100 mg orally twice daily for 14 days.
    • Metronidazole 500 mg orally twice daily for 14 days.
  • Inclusion of metronidazole addresses anaerobic bacteria contributing to PID.

Syphilis:

• Stages and Presentation:

• Primary Syphilis:

• • • Painless chancre on genitals.
    • Treatment: Penicillin G 2.4 million units IM single dose.

• Secondary Syphilis:

• • • Rash (often diffuse), mucocutaneous lesions, nonspecific joint pain.
    • Treatment: Same as primary syphilis.

• Latent Syphilis:

• • • Asymptomatic phase; divided into early (<1 year) and late (>1 year).

• Treatment for Late Latent:

• • Penicillin G 2.4 million units IM once weekly for 3 weeks.
  • Recommended when the timing of infection is unclear.

Neurosyphilis:

• Can occur at any stage.
• Symptoms include visual changes, severe headaches, neurological deficits.

• Diagnosis: Requires lumbar puncture (LP) for confirmation.
• Treatment: Admission for intravenous penicillin G.

Tertiary Syphilis:

• Rare, advanced stage with severe manifestations (e.g., gummas, cardiovascular complications, neurological signs).
• Treatment: Extended penicillin therapy similar to late latent syphilis.

Trichomoniasis:

• Presentation:

• • • Often asymptomatic.
    • In women: Vaginal discharge.
    • In men: Urethritis.

• Testing:

• • • Shift from wet mount microscopy to NAAT for improved detection.
    • Swab samples preferred over urine for higher sensitivity.

• Treatment Updates:

• • • Previous Regimen: Metronidazole 2 g orally in a single dose.

• Current Recommendations:

• • • Women: Metronidazole 500 mg orally twice daily for 7 days.
    • Men: Single 2 g dose remains acceptable.

Herpes Simplex Virus (HSV):

• Types and Transmission:

• • • HSV-1 and HSV-2: Both can cause oral and genital infections.
    • Increasing crossover between oral and genital sites.

• Testing:

• • • Serum IgG testing not useful for acute diagnosis due to widespread prior exposure.
    • Preferred Method: PCR testing from lesion swabs.
  • Clinical Tip: If the lesion is characteristic, clinicians may start treatment without waiting for test results.

• Treatment:

• • • Preferred Medication: Valacyclovir (Valtrex) for ease of dosing.

• Dosage:

• • • Initial episode: 1 g orally twice daily for 7 to 10 days.
    • Recurrence: 1 g daily for 5 days.
  • Alternative: Acyclovir for cost considerations.

Human Immunodeficiency Virus (HIV):

• Testing Limitations:

• Window Periods:

• • • • Fourth-generation tests have a window period of 2 to 4 weeks.
      • Negative results during this period may not rule out recent infection.

• Acute HIV Infection:

• • • Presents with flu-like symptoms: malaise, joint pains, fatigue.

• Diagnosis Challenges:

• • • Standard HIV tests may be negative during the window period.

• Options:

• • • • Empiric treatment with follow-up testing.
      • Order an HIV viral load test (more sensitive but expensive and delayed results).

• Post-Exposure Prophylaxis (PEP):

• • • Timing: Initiate ideally within 72 hours of potential exposure.
    • Duration: 28-day regimen.

• Pre-Treatment Testing:

• • Baseline HIV test to rule out existing infection.
  • Renal and hepatic function tests to monitor for medication side effects.
• Follow-Up: Reassess renal/hepatic function in 2 weeks.

Mycoplasma genitalium:

• Recognition:

• • • Newly recognized STI by the CDC in 2021.
    • Causes cervicitis and urethritis.
    • Possible associations with PID and proctitis, but not definitively established.

• Testing:

• When to Test:

• • • • Only in patients with persistent symptoms after standard STI testing and treatment.
      • Not recommended for initial screening.
    • Method: NAAT.

• Treatment:

• • • Step 1: Doxycycline 100 mg orally twice daily for 7 days.
    • Step 2: Moxifloxacin 400 mg orally once daily for 7 days.
    • Addresses antibiotic resistance concerns and ensures comprehensive treatment.

• General Management and Patient Counseling:

• Partner Notification:

• • • • Encourage patients to inform sexual partners for testing and treatment.

• Medication Adherence:

• • • • Emphasize the importance of completing the full course of prescribed medications.

• Prevention Measures:

• • • • Discuss the use of barrier protection (e.g., condoms) to prevent transmission and reinfection.

• Follow-Up Care:

• • • Advise patients to return if symptoms persist, indicating possible infections like Mycoplasma genitalium.

Key Take-Home Points:

• Chlamydia Treatment Update:

• • • Doxycycline 100 mg orally twice daily for 7 days is now first-line treatment for cervical infections.
    • For epididymitis, extend doxycycline to 10 days.

• Gonorrhea Treatment Update:

• • • Treat with a single 500 mg IM dose of ceftriaxone.

• PID Management Update:

• • • Expanded antimicrobial coverage includes:
      • Ceftriaxone 500 mg IM once.
      • Doxycycline 100 mg orally twice daily for 14 days.
      • Metronidazole 500 mg orally twice daily for 14 days.

• Mycoplasma genitalium Recognition:

• • • Test in patients with persistent symptoms after standard treatment.
    • Treat with doxycycline followed by moxifloxacin.

• HIV Testing and PEP:

• • Be aware of HIV test window periods; negative results may not rule out recent infection.
  • Consider HIV viral load testing if acute infection is suspected.
  • Initiate PEP within 72 hours for a 28-day course, ensuring clear discharge planning and patient support.