Sexually Transmitted Disease

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Epidemiology
Risk Factors: High Risk Groups for STD
Pathophysiology: Transmission
Causes
Findings: Genitourinary Gonorrhea or Chlamydia (Male)
Findings: Genitourinary Gonorrhea or Chlamydia (Female)
Findings: Extra-Genital Gonorrhea or Chlamydia
Precautions
Labs: Screening First-Line
Differential Diagnosis
Management
Management: Expedited Partner Treatment
Prevention: Including Post-exposure Prophylaxis
Prevention: Doxycycline Post-Exposure Prophylaxis (Doxy PEP)
Prevention: Screening Asymptomatic Patients (USPTF guidelines)
Resources: Patients
References
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II. Epidemiology

More than 20 million Sexually Transmitted Infections in the U.S. per year (as of 2022)
Human Papillomavirus (HPV) is the most common U.S. Sexually Transmitted Infection (and preventable with the HPV Vaccine)
Trichomonas vaginalis is the most common non-viral U.S. Sexually Transmitted Infection
Chlamydia trachomatis and Mycoplasma Genitalium are the first and second most common U.S. Sexually Transmitted Infection

III. Risk Factors: High Risk Groups for STD

Adolescents and young adults (ages 15 to 24 years old)
1. Multiple partners
2. Sequential monogamy
3. Unconcerned
4. Uniformity
5. Inconsistent Condom use
Racial or ethnically skewed
1. Black: Chlamydia more common
Homosexual men (or Men who have Sex with Men)
Transgender Person
Coasts or Ports of entry
Prostitutes
Teenage runaways
Immigrants
Low income in urban setting
Prison Inmate (current or former)
Military recruits
Mental Illness
Injection drug user (IV Drug Abuse)
Sexual Abuse history
Sexually Transmitted Infection history

IV. Pathophysiology: Transmission

Contact
1. Secretions
2. Mucus membrane
3. Skin Abrasion
Intercourse not necessary for STD transmission
1. Herpes Simplex Virus
2. Condyloma
3. Gonorrhea
4. Chlamydia

V. Causes

Sexually Transmitted Disease Genital Ulcers
1. See Genital Ulcers (Mnemonic: CHISEL)
  1. E in CHISEL is Drug Eruption
2. Painful Ulcers
  1. Chancroid
  2. Herpes Genitalis
  3. Trichomonas may also cause labial ulcerations
3. Non-Painful Ulcers
  1. Granuloma Inguinale
  2. Syphilis (Early)
  3. Lymphogranuloma venereum
Sexually Transmitted Disease Non-ulcerative
1. Bacterial
  1. See Non-Gonococcal Urethritis
  2. Pelvic Inflammatory Disease
  3. Gonorrhea
  4. Chlamydia
  5. Syphilis (Secondary or tertiary)
2. Viral Infections
  1. Human Papillomavirus (HPV) and Cervical Dysplasia
  2. Human Immunodeficiency Virus (HIV)
  3. Hepatitis B Virus
3. Parasitic Infection
  1. Pediculosis Pubis
  2. Scabies (pruritic genital bumps awaken patient)
Emerging Sexually Transmitted Infections
1. Monkeypox
2. Hepatitis A Virus
3. Mycoplasma Genitalium
4. Zika Virus
5. Lymphogranuloma venereum (LGV)
  1. Presents with Inguinal Lymphadenopathy or Proctitis
6. Shigella flexneri
  1. Associated with anal sex and oro-anal sex, and presents with severe Diarrhea
  2. Multi-drug resistant and treatment requires susceptibility testing
  3. Associated with HIV Infection
7. Neisseria Meningitidis
  1. Colonizes oropharynx of up to 10% of the U.S.
    1. Colonization of the Urethra, Cervix and Rectum has been found
    2. As of 2023, symptomatic localized infection responds to single dose Azithromycin or Ceftriaxone
  2. Cohorts of STI
    1. Urethritis in men who have sex with women
    2. Invasive meningococcal disease in Men who have Sex with Men

VI. Findings: Genitourinary Gonorrhea or Chlamydia (Male)

Symptoms
1. Dysuria
2. Urinary Frequency
3. Urethral meatus discharge
4. Urethral Pruritus
5. Painful ejaculation
Signs
1. Mucopurulent Urethral discharge
2. Unilateral Testicular Pain
Complications
1. Acute Prostatitis
2. Epididymitis

VII. Findings: Genitourinary Gonorrhea or Chlamydia (Female)

Symptoms
1. Vaginal Discharge
2. Postcoital spotting
3. Dyspareunia
Signs
1. Genital Ulcers
2. Cervicitis
  1. Erythema of Cervix
  2. Mucopurulent discharge from Cervical os
Complications
1. Pelvic Inflammatory Disease
  1. Fever, uterine and Adnexal tenderness, cervical motion tenderness, Vaginal Discharge
2. Perihepatitis (Fitz-Hugh-Curtis Syndrome)
  1. Pelvic Pain and right upper quadrant pain with fever, Vomiting and abnormal LFTs

VIII. Findings: Extra-Genital Gonorrhea or Chlamydia

Oropharyngeal Findings
1. Pharyngitis
2. Oropharyngeal exudate
3. Cervical Lymphadenitis
Anorectal Findings (also caused by syphillis, HSV, in addition to GC and Chlamydia)
1. Anal Pruritus
2. Rectal Pain
3. Pain with anorectal intercourse
4. Rectal Bleeding
5. Rectal discharge
6. Tenesmus
Reactive Arthritis (Reiter's Syndrome)
1. Aseptic Arthritis
2. Conjunctivitis
3. Urethritis
Lymphogranuloma venereum (Chlamydia)
1. Unilateral, swollen and tender inguinal or femoral Lymph Nodes
2. Ulcer or Papule overlying Lymph Nodes may be present
3. Fever
4. Rectal symptoms
  1. Rectal Bleeding
  2. Rectal mucoid discharge
  3. Rectal Pain
  4. Tenesmus
  5. Constipation
Disseminated Gonococcal Infection
1. Migratory polyarthritis (asymmetric, Pauciarticular)
2. Tenosynovitis
3. Fever
4. Dermatitis (distal extremity necrotic lesions)
5. May be complicated by endocarditis or Meningitis

IX. Precautions

Only 30% of Sexually Transmitted Infections are symptomatic
Dysuria is not synonymous with Urinary Tract Infection (UTI)
1. Consider Sexually Transmitted Infection (STI) in sexually active women presenting with Dysuria
2. Urine White Blood Cells and positive Leukocyte esterase are seen in both UTIs as well as STIs
Extra-genital sites of Gonorrhea and Chlamydia infection are often missed
1. Ask a Sexual History including practices, and screen oropharynx and Rectum as indicated
2. Urine-Only screening may miss Sexually Transmitted Infection in >80% of patients
  1. Marcus (2011) Sex Transm Dis 38(10): 922-4 [PubMed]
3. Pharyngeal Gonorrhea in Men who have Sex with Men
  1. Morris (2006) Clin Infect Dis 43: 1284-9 [PubMed]
4. Pharyngeal and Rectal Gonorrhea, and Rectal Chlamydia in women who have sex with men
  1. Bamberger (2019) Sex Transm Dis 46(5): 329-34 [PubMed]
Pregnancy-related Sexually Transmitted Infection
1. See Chorioamnionitis
2. See Postpartum Endometritis
3. See TORCH Infection
4. STI in pregnancy is high risk for complications (e.g. IUGR, PROM, Stillbirth, preterm birth, neonatal infection)
5. Universal screening in all pregnant women under age 25 years at first Prenatal Visit (and often in all women)
6. Rescreen pregnant women in 4 weeks after completing STI treatment, and again in 3 months, and third trimester
Neonatal and Perinatal Sexually Transmitted Infection
1. See Perinatal HIV Transmission
2. See Neonatal Herpes Simplex Virus
3. See Perinatal Hepatitis B Exposure
4. See Congenital Syphilis
5. Gonorrhea
  1. Perinatal Gonorrhea infection affects up to 0.4 cases in 100,000 U.S. live births
  2. Risk of gonococcal Ophthalmia Neonatorum (risk of newborn blindness if prophylaxis is not used)
  3. Risk of Disseminated Gonorrhea infection in newborns (e.g. Septic Arthritis, Meningitis, Pneumonia)
6. Chlamydia
  1. Risk of chlamydia Ophthalmia Neonatorum (later presentation than with Gonorrhea)
  2. Risk of Neonatal Chlamydia Pneumonia

X. Labs: Screening First-Line

Genitourinary Gonorrhea and Chlamydia Testing
1. Tests
  1. Chlamydia DNA Probe
  2. Gonorrhea DNA probe
2. Sources
  1. First-Stream Urine without Urethral Cleansing ("Dirty Urine")
    1. Preferred sample in men and women (equivalent to endocervical, vaginal or Urethral swabs)
  2. Other sources
    1. Endocervical swab on female speculum exam
    2. Provider or patient performed vaginal swabs
    3. Urethral swabs (men)
  3. References
    1. Lunny (2015) PLoS One 10(7): e0132776 [PubMed]
    2. Ronn (2019) BMJ Open 9(1): e022510 [PubMed]
Extragenital Testing (pharynx, Rectum) for Gonorrhea and Chlamydia
1. Several DNA and NAAT are approved for extragenital testing (e.g. Aptima Combo 2, Xpert CT/NG)
Point-of-care tests are available for Gonorrhea and Chlamydia genitourinary and extra-genital testing
1. Binx IO Point-Of-Care Test for female cervical swabs and male urine tests
  1. High accuracy with results in 30 minutes
  2. Clebak (2022) Am Fam Physician 106(5): 575-7 [PubMed]
Vaginal Exam
1. Trichomonas DNA probe
  1. Replaces Wet Prep which only has a 50 to 65% Test Sensitivity for Trichomonas
2. Vaginal Wet Prep
  1. Positive: Polymorphonuclear Leukocytes (PMNs) >10/hpf
    1. Positive test should be followed by specific DNA testing for Chlamydia and Gonorrhea
  2. Efficacy
    1. Test Sensitivity: 90%
    2. Test Specificity: 87%
  3. Reference
    1. Bohmer (1999) Am J Obstet Gynecol 181:283-7 [PubMed]
Broad STI Screening in those at risk, including those testing positive for Gonorrhea and Chlamydia
1. HIV Test
2. Syphilis (RPR)
3. Hepatitis B Testing (if not immunized)
Other Testing to consider
1. Consider Urinalysis
2. Consider Urine Pregnancy Test

XI. Differential Diagnosis

Conjunctivitis
1. See Bacterial Conjunctivitis
2. See Conjunctivitis in Newborns
Urethritis
1. See Urethritis
2. See Urethritis in Women
3. See Urethritis in Men
4. See Epididymitis
5. See Acute Prostatitis
Vaginitis
1. See Vaginitis
2. See Acute Cervicitis
3. See Pelvic Inflammatory Disease
Other Findings
1. See Pharyngitis Causes
2. See Proctitis
3. See Inguinal Lymphadenopathy
4. See Polyarticular Arthritis

XII. Management

Emergency department empiric treatment
1. Initiating empiric treatment for suspected STD prior to results (often delayed days) is appropriate
2. Despite risk of overtreatment, treat for suspected Chlamydia and Gonorrhea (prevents spread, complications)
  1. Gonorrhea management
    1. Ceftriaxone 500 mg IM/IV for 1 dose (1 gram IM/IV if weight > 150 kg, dose increased in 2020) OR
    2. Gentamicin 240 mg IM and Azithromycin 2 g orally for one dose OR
    3. Cefixime 800 mg orally once is an alternative but NOT recommended due to Antibiotic Resistance
  2. Chlamydia management if not excluded (not indicated for Gonorrhea treatment without Chlamydia as of 2020)
    1. Doxycycline 100 mg twice daily for 7 days (preferred as of 2020) OR
    2. Azithromycin 1 g orally for 1 dose
  3. References
    1. Cyr (2020) MMWR Morb Mortal Wkly Rep 69(50): 1911-6 [PubMed]
      1. https://www.cdc.gov/mmwr/volumes/69/wr/mm6950a6.htm
3. Avoid sexual contact until Antibiotic course is completed
Rescreening
1. Routinely Rescreen positive STD cases in 3 months to identify new STD infections
2. Rescreen pregnant women in 4 weeks after completing treatment, and again in 3 months, and in third trimester
3. Only other indicated early rescrening at 7 to 14 days (screening for cure) is for pharyngeal Gonorrhea
4. Peterman (2006) Ann Intern Med 145:654-72 [PubMed]
Clinic Visits
1. Symptomatic patients should have in-person clinical examinations
2. Consider Telemedicine for Sexually Transmitted Infection screening in asymptomatic patients
  1. At-home Chlamydia trachomatis and Neisseria Gonorrhea tests are available (not FDA approved)
  2. Medical provider or nurse instructed sample self-collection can be instructed on Telemedicine
  3. At home Test Sensitivity may be lower, but allows for screening more patients with fewer barriers
  4. Canevale (2021) Sex Transm Dis 48(1): e11-4 [PubMed]
  5. Fajardo-Bernal (2015) Cochrane Database Syst Rev (9):CD011317 [PubMed]
  6. Kersh (2021) J Clin Microbiol 59(11): e0264620 [PubMed]

XIII. Management: Expedited Partner Treatment

Empiric STI treatment for an asymptomatic sexual partner of a patient being seen for STI
1. Patient positive for Chlamydia or Gonorrhea in last 60 days (or last sexual partner if >60 days)
2. Symptomatic sexual partners should be medically evaluated
Precaution: Legality of Expedited Partner Treatment varies by State in the United States
1. http://www.cdc.gov/std/ept/legal/
2. As of 2022, permitted in 46-49 states (not legal in South Carolina)
Patients may anonymously notify their partner
1. https://tellyourpartner.org/
Ideally sexual partners are seen for their own medical evaluations
1. However, delaying their treatment until evaluation risks re-exposing treated patients
CDC asks physicians to consider treating sexual partners of STD patients without a visit
1. Employ in cases where sexual partner is unlikely to present for medical care
2. Prescription for sexual partner's STD treatment is given to the patient being treated
3. Some states may allow prescription labeled for "EPT" or "partner"
4. Do not double up on prescription quantity for one patient (write 2 separate prescriptions)
Example protocol for partner (prescriptions given to patient to bring to partner)
1. Provider should ask about partner's medication allergies, other medications and pregnancy
2. Written instructions should be given to the patient to convey to their sexual partner
3. Patient and their partner should abstain from sex until both have completed Antibiotic course
Regimen
1. Cefixime 800 mg (if partner will be seen, Ceftriaxone 500 mg IM/IV is preferred) AND
2. Azithromycin 1 gram orally (or preferred option is Doxycycline 100 mg twice daily for 7 days)
References
1. (2015) Presc Lett 22(8)
2. Golden (2005) N Engl J Med 352:676-85 [PubMed]
3. (2015) MMWR Recomm Rep 64(RR-03): 1-137 +PMID:26042815 [PubMed]

XIV. Prevention: Including Post-exposure Prophylaxis

Consistent Condom Use
Vaccination
STI Postexposure Prophylaxis
1. See Sexual Assault
2. See Doxy PEP below
3. HIV Postexposure Prophylaxis
Other measures
1. HIV Preexposure Prophylaxis (HIV PrEP)
2. Expedited Partner Treatment (see above)

XV. Prevention: Doxycycline Post-Exposure Prophylaxis (Doxy PEP)

Encourage safe sex practices (e.g. Condoms, and other PEP/PREP)
Indications
1. Bacterial STI in the last year (Syphilis, Gonorrhea, Chlamydia) AND
2. Specific high risk patients
  1. Men who have Sex with Men (MSM)
  2. Transgender women (TGW)
Protocol
1. See Doxycycline for precautions (take with 8 oz fluid, avoid with Antacids, use Sunscreen)
2. Patient takes 200 mg Doxycycline as soon as possible after sex (oral, vaginal, anal) and within 72 hours
3. Limit to one dose in 24 hours
Efficacy
1. NNT 3 to prevent one Bacterial STI per year
References
1. Stewart (2022) Trials 23(1):495 +PMID: 35710444 [PubMed]
2. Luetkemeyer (2022) AIDS 2022 Conference Abstract
  1. https://programme.aids2022.org/Abstract/Abstract/?abstractid=13231

XVI. Prevention: Screening Asymptomatic Patients (USPTF guidelines)

See Risk Factors listed above
Behavioral counseling (proper Condom use, safe sex, difficult sexual situations)
1. All sexually active adolescents
2. Adults at risk for Sexually Transmitted Infection
3. Emphasize barrier protection (e.g. Condoms) as best method to prevent Sexually Transmitted Infection during sex
Gonorrhea and Chlamydia screening
1. All sexually active adolescents 24 years old and younger every year (and repeated 3 months after positive testing)
2. Women at risk for Sexually Transmitted Infection
3. Pregnancy age <= 24 years or any age if high risk (at first visit, and if risk then repeat in third trimester)
4. Men who have Sex with Men (consider rectal and pharyngeal screening as well)
5. Correctional facilities at intake (men age <30 years, women age <35 years)
HIV Screening
1. All patients ages 15 years old to 65 years old (or if risks)
2. All pregnant women at first Prenatal Visit (or at time of delayed presentation)
Hepatitis B Virus Screening
1. All pregnant women at first Prenatal Visit (or at time of delayed presentation)
2. Patients at risk of infection
  1. Immigrants from sub-sahara Africa, Central and Southeast Asia, China (esp. unimmunized)
  2. Household HBV Contacts
Syphilis Screening
1. All pregnant women at first Prenatal Visit (or at time of delayed presentation)
2. Patients at risk of infection
Herpes Simplex Virus Infection Screening
1. USPTF and AAFP
  1. Do NOT routinely screen HSV Serology in asymptomatic patients
2. CDC and ACOG
  1. Consider type-specific Serology in women at time of STI evaluation (esp. if multiple partners)
References
1. Lee (2016) Am Fam Physician 94(11): 907-15 [PubMed]

XVII. Resources: Patients

CDC National STD Hotline (CDC)
1. http://www.cdc.gov/std/
2. Phone: 800-232-4636
Expedited Partner Treatment (CDC)
1. http://www.cdc.gov/std/ept/
Information from your Family Doctor: Prevent AIDS
1. http://www.familydoctor.org/healthfacts/005/
Inspot.Org (annonymously notify others of STD exposure)
1. https://inspot.org/
DontSpreadIt.Com (annonymously notify others of STD exposure)
1. https://dontspreadit.com/

XVIII. References

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