Managing Sexually Transmitted Infections

---
name: managing-sexually-transmitted-infections
language: en
description: Guides STI screening, treatment, and partner notification using CDC guidelines. Use when managing STIs, selecting treatment regimens, or documenting STI screening.
tags:
  - management
  - obstetrics-and-gynecology
  - treatment
metadata:
  author: casemark
  practice_areas:
    - Obstetrics
    - Gynecology
    - Maternal-Fetal Medicine
  document_types:
    - Management Report
  skill_modes:
    - Management
    - Coordination
---

# Managing Sexually Transmitted Infections

Guides STI screening, diagnosis, treatment, and partner notification using CDC STI Treatment Guidelines (2021, with 2023–2024 updates) within the OB/GYN clinical context.

## Why This Skill Exists

Sexually transmitted infections (STIs) affect approximately 26 million new cases annually in the United States. In OB/GYN practice, STI management is critical across multiple contexts: routine screening, prenatal care (where untreated infections cause congenital syphilis, neonatal herpes, ophthalmia neonatorum, and preterm birth), infertility evaluation (tubal factor from Chlamydia), and abnormal cervical cytology workup. The CDC STI Treatment Guidelines are the definitive reference for screening intervals, diagnostic testing, and antimicrobial regimens.

Antimicrobial resistance — particularly in Neisseria gonorrhoeae — has narrowed treatment options and mandates strict adherence to current regimens. This skill ensures that screening is age- and risk-appropriate, treatment follows current CDC recommendations, and partner management is addressed.

---

## Checkpoint A: Pre-Draft Intake (Mandatory)

1. **Clinical presentation** — symptoms (discharge, dysuria, genital lesions, pelvic pain) or asymptomatic screening? (Default: from chief complaint)
2. **Sexual history** — number of partners, partner sex (MSM, MSW, WSW), condom use, new partner in past 60 days? (Default: use 5 P's framework — Partners, Practices, Protection, Past STIs, Pregnancy prevention)
3. **Pregnancy status** — pregnant? Gestational age? (Default: from chart — critical for regimen selection)
4. **HIV status** — known positive, negative with last test date, or unknown? (Default: from lab records)
5. **Prior STI history** — prior infections, treatments, complications (PID, ectopic)? (Default: from history)
6. **Drug allergies** — cephalosporin allergy, penicillin allergy (relevant for syphilis treatment)? (Default: from allergy list)
7. **Age** — determines routine screening recommendations. (Default: from demographics)
8. **Vaccination status** — Hepatitis A, Hepatitis B, HPV vaccine? (Default: from immunization record)

### Documents to Request

- Prior STI test results
- Current test results (NAAT for CT/GC, RPR/VDRL, HIV, Hep B/C serologies, HSV serologies if applicable)
- HIV status documentation
- Immunization records (HBV, HPV, HAV)
- Pregnancy test results
- Drug allergy documentation
- Partner treatment records (if available)

---

## Step 1: Apply CDC Screening Recommendations

### Routine Screening by Population

| Population | Recommended Screening |
|---|---|
| All women < 25 years (sexually active) | Chlamydia and gonorrhea annually |
| Women ≥ 25 with risk factors | Chlamydia and gonorrhea annually (new partner, multiple partners, partner with STI) |
| All pregnant women (first prenatal visit) | Chlamydia, gonorrhea, syphilis (RPR/VDRL), HIV, Hepatitis B (HBsAg) |
| Pregnant women at high risk | Repeat chlamydia/gonorrhea/syphilis in 3rd trimester (28–36 weeks) |
| MSM (all sexually active) | Chlamydia, gonorrhea (pharynx, rectum, urine), syphilis, HIV — at least annually; q3 months if high risk |
| HIV-positive individuals | Syphilis, chlamydia, gonorrhea at least annually; more frequent if high risk |
| All adults 15–65 | HIV screening at least once (opt-out); repeat if risk factors |

### Testing Methods
- **Chlamydia and gonorrhea:** NAAT (nucleic acid amplification test) — urine, endocervical, vaginal, pharyngeal, rectal as indicated
- **Syphilis:** RPR or VDRL (screening) → treponemal test (FTA-ABS or TP-PA) for confirmation; OR reverse algorithm (treponemal first)
- **HIV:** 4th generation Ag/Ab combo test (preferred) → confirmatory HIV-1/HIV-2 differentiation
- **Herpes:** Type-specific serology (HSV-1 IgG, HSV-2 IgG) only if clinical indication; NOT recommended as routine screen
- **Trichomoniasis:** NAAT (preferred) or wet mount; screen all HIV-positive women annually

---

## Step 2: Treatment Regimens (CDC 2021 with Updates)

### Chlamydia (Chlamydia trachomatis)

| Setting | Regimen |
|---|---|
| Non-pregnant | Doxycycline 100 mg PO BID × 7 days (preferred — now first-line per 2021 update) |
| Pregnant | Azithromycin 1 g PO single dose |
| Test of cure | Not routine except in pregnancy (repeat NAAT at 4 weeks after treatment) |
| Rescreening | Retest at 3 months (high reinfection rate) |

### Gonorrhea (Neisseria gonorrhoeae)

| Setting | Regimen |
|---|---|
| Uncomplicated (cervical, urethral, rectal) | Ceftriaxone 500 mg IM single dose (1 g if weight ≥ 150 kg) |
| Pharyngeal | Ceftriaxone 500 mg IM single dose |
| If cephalosporin allergy | Gentamicin 240 mg IM + azithromycin 2 g PO (consult ID) |
| Pregnant | Ceftriaxone 500 mg IM single dose |
| Co-treatment for chlamydia | Doxycycline 100 mg PO BID × 7 days (unless pregnant → azithromycin 1 g PO) |
| Test of cure | Pharyngeal gonorrhea: test of cure NAAT at 7–14 days; cervical/urethral: only if concern for treatment failure |

### Syphilis (Treponema pallidum)

| Stage | Regimen |
|---|---|
| Primary, secondary, or early latent (< 1 year) | Benzathine penicillin G 2.4 million units IM × 1 dose |
| Late latent (> 1 year or unknown duration) | Benzathine penicillin G 2.4 million units IM weekly × 3 doses |
| Tertiary (gummatous, cardiovascular) | Benzathine penicillin G 2.4 million units IM weekly × 3 doses |
| Neurosyphilis / ocular / otic | Aqueous crystalline penicillin G 18–24 million units/day IV × 10–14 days |
| Pregnant (any stage) | Penicillin G (stage-appropriate dose) — penicillin is the ONLY acceptable treatment in pregnancy; desensitize if allergic |
| Jarisch-Herxheimer reaction | May occur within 24 hours of treatment; supportive care; in pregnancy, may trigger preterm labor — monitor |

### Genital Herpes (HSV)

| Scenario | Regimen |
|---|---|
| First episode | Valacyclovir 1 g PO BID × 7–10 days |
| Recurrent episodes | Valacyclovir 500 mg PO BID × 3 days (or 1 g daily × 5 days) |
| Suppressive therapy | Valacyclovir 500 mg PO daily (for ≥ 6 episodes/year or to reduce transmission) |
| Pregnant (≥ 36 weeks) | Acyclovir 400 mg PO TID or valacyclovir 500 mg PO BID from 36 weeks to delivery to reduce recurrence and cesarean need |

### Trichomoniasis (Trichomonas vaginalis)

| Setting | Regimen |
|---|---|
| Non-pregnant women | Metronidazole 500 mg PO BID × 7 days (preferred per 2021 update; single dose now NOT recommended for women) |
| Pregnant | Metronidazole 500 mg PO BID × 7 days (safe in all trimesters) |
| Men | Metronidazole 2 g PO single dose |
| Treat partners | Simultaneous treatment of all sexual partners |

---

## Step 3: Pelvic Inflammatory Disease (PID) Management

PID is a clinical diagnosis; do not wait for culture confirmation.

### Diagnostic Criteria (CDC)
Minimum: uterine tenderness, adnexal tenderness, OR cervical motion tenderness in a sexually active young woman with no other identifiable cause.

### Treatment

| Setting | Regimen |
|---|---|
| Outpatient | Ceftriaxone 500 mg IM × 1 + doxycycline 100 mg PO BID × 14 days + metronidazole 500 mg PO BID × 14 days |
| Inpatient | Cefotetan 2 g IV q12h + doxycycline 100 mg IV/PO q12h; OR cefoxitin 2 g IV q6h + doxycycline 100 mg IV/PO q12h |

Inpatient criteria: surgical emergency not excluded, tubo-ovarian abscess, pregnancy, severe illness, unable to tolerate PO, failure of outpatient therapy.

---

## Step 4: Partner Management and Reporting

- **Expedited partner therapy (EPT):** Prescribe treatment for partner(s) without clinical evaluation — legal in most states; check state law
- **Partner notification:** Recommend patient inform partners from the past 60 days (CT/GC) or based on staging (syphilis)
- **Reportable diseases:** Chlamydia, gonorrhea, syphilis, and HIV are reportable to the state health department in all US states
- **Congenital syphilis:** report maternal and neonatal cases; inadequately treated maternal syphilis requires neonatal evaluation and treatment

---

## Checkpoint B: Post-Draft Alignment (Mandatory)

1. **Is the correct test type used** — NAAT for CT/GC, serology for syphilis/HIV?
2. **Does the treatment regimen match** the current CDC guidelines (2021 with updates)?
3. **Is pregnancy status confirmed** and the regimen pregnancy-safe?
4. **Is partner management addressed** — EPT offered and/or partner notification counseled?
5. **Is rescreening scheduled** at 3 months for CT/GC per CDC recommendation?

---

## Quality Audit

- [ ] Sexual history documented using structured framework (5 P's)
- [ ] Age- and risk-appropriate screening performed per CDC recommendations
- [ ] Correct test methodology used (NAAT for CT/GC, serology for syphilis/HIV)
- [ ] Treatment regimen matches current CDC guidelines (drug, dose, route, duration)
- [ ] Pregnancy status confirmed before treatment selection
- [ ] Drug allergies checked (penicillin allergy documented for syphilis cases)
- [ ] Co-treatment for chlamydia included with gonorrhea treatment (if not tested)
- [ ] Partner management addressed (EPT, partner notification, or both)
- [ ] Rescreening at 3 months documented for CT and GC
- [ ] Test of cure scheduled when indicated (pregnancy, pharyngeal GC)
- [ ] Reportable conditions reported to health department
- [ ] HIV testing offered (if not recently tested)
- [ ] Hepatitis B vaccination offered (if non-immune)
- [ ] HPV vaccination offered (if eligible, up to age 45)
- [ ] Condom counseling documented

---

## Guidelines

1. **Doxycycline is now first-line for chlamydia** — the 2021 CDC update changed the preferred regimen from azithromycin 1 g to doxycycline 100 mg BID × 7 days due to rising azithromycin resistance and better rectal CT cure rates.
2. **Single-dose metronidazole is no longer recommended for women with trichomoniasis** — the 7-day regimen has significantly better cure rates in women.
3. **Penicillin is the ONLY acceptable treatment for syphilis in pregnancy** — if the patient has a penicillin allergy, she must be desensitized and treated with penicillin; no alternative is adequate.
4. **Treat PID empirically** — the diagnosis is clinical; waiting for culture results delays treatment and risks tubal damage and infertility.
5. **Screen all prenatal patients for syphilis at intake** — congenital syphilis cases have increased dramatically; repeat screening in the third trimester in high-risk populations.
6. **Report all reportable infections** — chlamydia, gonorrhea, syphilis, and HIV are legally reportable in all jurisdictions; this is not optional.
7. **Offer HIV testing universally** — opt-out screening is recommended for all patients aged 15–65 and all pregnant women.