141.1 🎓 醫孞生版

141.1.0.1 📌 䞀頁重點

  • 流行病孞 (US 2023-24): STIs at record highs — Chlamydia > Gonorrhea > Syphilis > HIV
  • STI 症候矀分類:
    • Urethritis / cervicitis: GC, Chlamydia, M. genitalium, Trichomonas
    • Genital ulcer: HSV (#1), syphilis (#2), chancroid, LGV
    • PID: GC, Chlamydia, polymicrobial
    • Vaginitis: Candida, BV, Trichomonas
    • Genital warts: HPV
    • Systemic: HIV, syphilis, HBV, HCV, mpox
  • Empirical 治療 for symptomatic (don’t wait for results):
    • Urethritis/Cervicitis: Ceftriaxone 500 mg IM + Doxycycline 100 mg BID × 7 d (covers GC + Chlamydia)
    • PID: Ceftriaxone 500 IM + Doxycycline 100 PO × 14 d + Metronidazole 500 BID × 14 d
  • Screening (CDC 2024):
    • Sexually active women < 25: annual Chlamydia + GC
    • MSM: annual / q3-6 mo (depending risk)
    • HIV +: annual + at HIV diagnosis
    • Pregnant: HIV, HBV, HCV, syphilis, GC, Chlamydia (1st trim, repeat 3rd if risk)

141.1.0.2 1⃣ Major Pathogens — Quick Reference

病原 症候矀 治療
N. gonorrhoeae Urethritis, cervicitis, PID, DGI, conjunctivitis Ceftriaxone 500 mg IM × 1 + Doxy 100 BID × 7d
C. trachomatis Urethritis, cervicitis, PID, LGV Doxycycline 100 BID × 7 d (preferred 2021); Azithro 1g × 1 alt
Treponema pallidum Syphilis: 1° chancre / 2° rash / 3° gummas / neuro Penicillin G IM (1°, 2°, early latent: single dose 2.4 MU; late: 3 weekly; neuro: IV × 14 d)
HSV 1/2 Genital ulcer (painful, vesicular, recurrent) Acyclovir / Valacyclovir / Famciclovir
HPV Warts, cervical / anal cancer Cryotherapy / TCA / podophyllin; vaccine 預防
Trichomonas vaginalis Vaginitis (女) / urethritis (男) Metronidazole 2g single OR 500 BID × 7 d
M. genitalium Urethritis / cervicitis (NGU) Doxy 7d → Azithro 4d (sequential) or Moxifloxacin if resistance
Haemophilus ducreyi Chancroid (painful ulcer + adenopathy) Azithromycin 1g single
Mpox Anogenital lesions, lymphadenopathy Supportive + tecovirimat (severe)
HIV (See Ch HIV) ART (TAF/FTC + DTG-based)

141.1.0.3 2⃣ Genital Ulcer Differential

病原 疌痛 邊緣 æ·‹å·Žè…«
HSV +++ painful Vesicular cluster Mild bilateral tender
Syphilis 1° Painless Indurated, clean base Painless, non-tender
Chancroid (H. ducreyi) Painful Ragged, purulent Painful, suppurative buboes
LGV (Chlamydia L1-L3) Painless (early) Small, transient Tender, “groove sign”
Granuloma inguinale Painless Beefy red, friable None
Behçet’s (not STI) Painful Aphthous Variable

141.1.0.4 3⃣ Urethritis / Cervicitis

141.1.0.4.1 Etiology
  • N. gonorrhoeae
  • C. trachomatis (60-70% of NGU non-gonococcal urethritis)
  • M. genitalium (15-25% of NGU)
  • Trichomonas, HSV, adenovirus
141.1.0.4.2 Diagnosis
  • NAAT (PCR) for GC + Chlamydia (urine 1st-catch or urethral / cervical / pharyngeal / rectal swab)
  • M. genitalium NAAT for persistent NGU
  • Gram stain urethral discharge (Gram - intracellular diplococci = GC)
141.1.0.4.3 Treatment (CDC 2021)
  • Gonorrhea: Ceftriaxone 500 mg IM × 1 (was 250; doubled 2020 for resistance) + Doxy 100 BID × 7 d if Chlamydia not ruled out
  • Chlamydia: Doxycycline 100 mg BID × 7 d (preferred 2021; replaces azithro 1g single)
  • M. genitalium: doxy 7d → azithro 4d sequential OR moxifloxacin (resistance)
141.1.0.4.4 Disseminated Gonococcal Infection (DGI)
  • Tenosynovitis + migratory polyarthralgia + pustular dermatitis (triad)
  • Ceftriaxone 1g IV q24h × 7-14 d

141.1.0.5 4⃣ Syphilis (Treponema pallidum)

141.1.0.5.1 Stages
Stage Time Features
Primary 3 wks-3 mo Chancre (painless ulcer); regional adenopathy
Secondary 4-10 wks Rash (palms + soles), condyloma lata, mucous patches, generalized adenopathy
Latent Months-years Asymptomatic; early latent < 1 yr, late latent > 1 yr
Tertiary 5-30 yrs Gummas, neurosyphilis, cardiovascular (aortitis)
141.1.0.5.2 Diagnosis
  • Treponemal test (FTA-ABS, TP-PA, EIA): first positive forever
  • Non-treponemal (RPR, VDRL): titer follow-up; converts to negative with treatment
  • Reverse algorithm (now standard): treponemal screen → non-treponemal confirm + titer
  • LP for neuro: CSF VDRL, FTA-ABS, lymphocytic pleocytosis, protein ↑
141.1.0.5.3 Treatment
Stage Treatment
Primary / Secondary / Early latent Benzathine penicillin G 2.4 MU IM single
Late latent / Latent unknown duration / Tertiary (non-CNS) Benzathine PCN 2.4 MU IM weekly × 3
Neurosyphilis / Ocular / Otosyphilis Aqueous PCN G 18-24 MU IV daily × 10-14 d
PCN allergy (non-pregnant) Doxycycline 100 BID × 14 d (early); × 28 d (late)
PCN allergy pregnant Desensitize + PCN (no alternative for fetal protection)
141.1.0.5.4 Jarisch-Herxheimer reaction
  • Fever, chills, myalgia 2-12 hr after first PCN dose
  • Treat with antipyretic; warn patient

141.1.0.6 5⃣ HSV (Genital Herpes)

141.1.0.6.1 Clinical
  • HSV-2 (more genital), HSV-1 rising (oral-genital)
  • Primary: severe; multiple painful vesicles; fever; adenopathy
  • Recurrent: milder, less frequent
  • Asymptomatic shedding: 倚 transmission source
141.1.0.6.2 Treatment
情境 Regimen
Primary (first episode) Acyclovir 400 TID × 7-10 d OR Valacyclovir 1g BID × 7-10 d OR Famciclovir 250 TID × 7-10 d
Recurrent Acyclovir 800 TID × 2 d OR Valacyclovir 500 BID × 3 d (episodic)
Suppression (frequent recurrences) Daily Valacyclovir 500 daily OR Acyclovir 400 BID
Pregnant (from 36 wks) Acyclovir suppression to reduce shedding at delivery