What are the risk factors, presenting symptoms, diagnostic strategies, treatment planning, and follow-up management for Sexually Transmitted Infections (STIs) in patients with various demographics and medical histories?

Sexually Transmitted Infections (STIs): Comprehensive Clinical Management

Risk Factors

The most significant modifiable risk factors for STI acquisition are multiple or new sexual partners, inconsistent condom use, and substance use during sexual activity. 1

High-Risk Demographics

• Age: Sexually active individuals under 25 years have the highest STI prevalence rates, with persons as young as 12 years potentially requiring screening 1
• Men who have sex with men (MSM): This population requires comprehensive screening at all anatomic sites of exposure (urogenital, rectal, oropharyngeal) 1, 2
• Geographic and racial disparities: African Americans have the highest STI prevalence of any racial/ethnic group, followed by American Indians, Alaska Natives, and Latinos; southern states and urban centers demonstrate higher rates 1
• Socioeconomic factors: Poverty, incarceration, low education level, and living in communities with high STI prevalence significantly increase risk 1, 3

Behavioral Risk Factors

• Sexual practices: Condomless vaginal, oral, or anal intercourse; multiple concurrent partners; anonymous partners 1, 4
• Substance use: Sex while using drugs or alcohol, particularly methamphetamine use 1
• Transactional sex: Exchanging sex for money or drugs 1
• Previous STI history: Prior or coexisting STI significantly increases risk of subsequent infections 1, 3

Critical Pitfall

Do not assume marital status provides protection—married men tested for gonorrhea and chlamydia were more than twice as likely to test positive compared to married women, though both groups had lower rates than single individuals 5

Presenting Symptoms

Most STIs are asymptomatic, making symptom-based diagnosis unreliable and emphasizing the critical importance of risk-based screening. 1

Symptomatic Presentations When Present

• Urethritis/cervicitis: Urethral or vaginal discharge, dysuria, mucopurulent cervical discharge 6
• Genital ulcers: Painless ulcers (syphilis), painful ulcers with lymphadenopathy (chancroid, herpes) 1, 7
• Systemic syphilis: Cutaneous or mucosal rashes, hair loss, lymphadenopathy, neurologic symptoms 1
• Pelvic inflammatory disease: Lower abdominal pain, cervical motion tenderness (complication of untreated chlamydia/gonorrhea) 6

Extragenital Manifestations

• Pharyngeal infections: Typically asymptomatic; may present as pharyngitis 1, 2
• Rectal infections: Often asymptomatic; may cause proctitis, rectal discharge, or pain 1, 2

Diagnostic Strategies

Nucleic acid amplification tests (NAATs) are the gold standard for diagnosing chlamydia, gonorrhea, and trichomoniasis due to superior sensitivity (86.1%-100%) and specificity (97.1%-100%) compared to culture or wet mount. 2, 6

Specimen Collection by Population

Women Under 25 Years or At-Risk

• Preferred: Vaginal swab NAAT for chlamydia and gonorrhea 1, 2, 6
• Acceptable: Cervical specimens 1, 2
• Additional: Vaginal swab NAAT for trichomoniasis 2

Men Who Have Sex With Men

• Urogenital: Urine NAAT for chlamydia and gonorrhea 2, 8
• Rectal: Rectal swab NAAT for chlamydia and gonorrhea (if engaging in receptive anal intercourse) 1, 2, 8
• Pharyngeal: Pharyngeal swab NAAT or culture for gonorrhea (if engaging in receptive oral sex) 1, 2, 8

Heterosexual Men

• Urogenital: Urine NAAT for chlamydia and gonorrhea 2

Syphilis Testing

Use the reverse algorithm approach: begin with treponemal-specific test (T. pallidum antibody via immunoassay), followed by nontreponemal testing (RPR or VDRL) to confirm active disease. 2

HIV Testing

• Fourth-generation testing: Combines HIV antibodies and p24 antigen detection, allowing earlier detection (2-4 weeks post-exposure versus 3-6 weeks for antibody-only tests) with automatic reflex to confirmatory testing if positive 2

Critical Diagnostic Pitfalls

• Do not rely on wet mount microscopy for trichomoniasis—it misses 30-40% of infections; use NAAT instead 2
• Do not perform urogenital testing only in MSM—extragenital infections account for 6-10% of infections and are frequently asymptomatic 8
• Do not assume negative screening provides ongoing protection—reassess sexual risk factors at each clinical encounter 2

Treatment Planning

Chlamydia and Gonorrhea Treatment

Non-Pregnant Adults

For cervicitis or urethritis, provide presumptive treatment before test results are available in high-prevalence settings (>5% gonorrhea prevalence). 6

• Chlamydia: Azithromycin 1 g orally single dose OR doxycycline 100 mg orally twice daily for 7 days 6, 9
• Gonorrhea: Requires dual therapy per current CDC guidelines (specific regimens not detailed in provided evidence but azithromycin is FDA-approved for gonorrhea) 9

Pregnant Women

• Treatment options: Azithromycin or amoxicillin for chlamydia or gonorrhea 6

Partner Management

All sex partners from the past 60 days must be notified, examined, and treated for the same STDs as the index patient, with presumptive treatment provided before test results when indicated. 1, 2

• Notification methods: Patient referral, provider referral, or public health official notification 1, 2
• Expedited partner therapy: Consider where legally permissible 1
• Abstinence requirement: Patients and partners must abstain from sexual intercourse for 7 days after single-dose therapy or until completion of 7-day regimen 6

Syphilis Treatment Considerations

Azithromycin at recommended doses should not be relied upon to treat syphilis; antimicrobial agents used for non-gonococcal urethritis may mask or delay symptoms of incubating syphilis. 9

• Mandatory serologic testing: All patients with sexually-transmitted urethritis or cervicitis require serologic testing for syphilis at diagnosis 9

Follow-Up Management

Post-Treatment Rescreening

Mandatory retesting at 3 months after treatment for all patients diagnosed with chlamydia or gonorrhea, regardless of whether partners were treated, due to reinfection rates of 25-40%. 1, 2, 6

• Chlamydia/gonorrhea: Retest at 3 months, or whenever patients next present for care within 12 months if 3-month testing not possible 1
• Trichomoniasis: Consider rescreening at 3 months for women previously diagnosed 1, 2

Ongoing Screening Frequency by Risk Group

Annual Screening

• All sexually active women under 25 years: Annual screening for chlamydia, gonorrhea, HIV, and syphilis 1, 2, 6
• Women 25 years and older with risk factors: Annual screening for chlamydia, gonorrhea, HIV, and syphilis 6
• Sexually active men at increased risk: Annual HIV and syphilis screening 1, 2
• MSM with standard risk: Annual screening for chlamydia, gonorrhea, syphilis, and HIV at all exposure sites 1, 8

Intensive Screening (Every 3-6 Months)

MSM and HIV-infected individuals with high-risk behaviors require screening every 3-6 months. 1, 2

• High-risk criteria: Multiple or anonymous partners, methamphetamine use, sex in conjunction with drug use, unprotected intercourse, or partners with these behaviors 1, 2, 8

Pregnancy-Specific Screening

All pregnant women require universal screening at first prenatal visit for hepatitis B, HIV, and syphilis. 1, 2, 6

• First prenatal visit: Hepatitis B surface antigen, HIV, syphilis for all pregnant women 2, 6
• Additional screening: Chlamydia and gonorrhea for pregnant women under 25 years or at increased risk 1, 2, 6
• High-risk women: Repeat syphilis testing in third trimester and at delivery 2, 6
• Critical requirement: No infant should be discharged without determination of mother's syphilis status at least once during pregnancy 2

Reporting Requirements

Syphilis, gonorrhea, and AIDS are reportable in every state; chlamydia is reportable in most states. 2, 6

• Clinicians must be familiar with local STD reporting requirements 2
• Contact local or state health departments for assistance with partner notification and community prevalence data 1

Prevention Counseling

Intensive behavioral counseling interventions (≥2 hours contact time) demonstrate the greatest effectiveness in reducing STI acquisition, with moderate-intensity interventions (30-120 minutes) showing less consistent benefit. 1

• Core components: Basic STI information, personalized risk assessment, skills training (condom use, communication, problem-solving, goal-setting) 1
• Delivery methods: Face-to-face counseling, videos, written materials, telephone support 1
• Preexposure vaccination: Hepatitis B vaccination recommended for all unvaccinated patients evaluated for STDs 1, 2