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Sexually Transmissible Infections

Approximately 12 million patients are diagnosed with a sexually transmissible infection (STI) annually in the United States. Sequella of STIs include infertility, chronic pelvic pain, ectopic pregnancy, and other adverse pregnancy outcomes.

I. Clinical evaluation

Diagnosis and Treatment of Bacterial Sexually Transmissible Infections


Diagnostic Methods

Recommended Treatment


Chlamydia trachomatis


Direct fluorescent antibody

Enzyme immunoassay

Nucleic acid hybridization (DNA probe)

Cell culture

DNA amplification

Doxycycline 100 mg orally 2 times a day for 7 days or

Azithromycin (Zithromax) 1 g orally

Ofloxacin (Floxin)300 mg orally 2 times a day for 7 days or

Erythromycin base 500 mg orally 4 times a day for 7 days or erythromycin ethylsuccinate 800 mg orally 4 times a day for 7 days.

Neisseria gonorrhoeae

Gram stain of endocervical smear


DNA probe

Ceftriaxone (Rocephin) 125 mg IM or

Cefixime 400 mg orally or

Ciprofloxacin (Cipro) 500 mg orally or

Ofloxacin (Floxin) 400 mg orally


Doxycycline 100 mg 2 times a day for 7 days or azithromycin 1 g orally

Spectinomycin 2 g IM or injectable cephalosporins given single IM dose such as ceftizoxime 500 mg, cefotaxime 500 mg, cefotetan 1 g IM, and cefoxitin (Mefoxin) 2 g IM with probenecid 1 g orally; or quinolones given single oral dose such as enoxacin 400 mg, lomefloxacin 400 mg, or norfloxacin 800 mg


Treponema pallidum

Clinical appearance

Dark-field microscopy

Nontreponemal serologic test

Rapid plasma reagin


Treponemal test



Primary and secondary syphilis and early latent syphilis (<1 year duration):

benzathine penicillin G 2.4 million units IM in a single dose.

Late latent syphilis or latent syphilis of unknown duration and late syphilis (gumma or cardiovascular syphilis, but not neurosyphilis): Benzathine penicillin G 7.2 million units total, as 3 doses of 2.4 million units IM, at 1-week intervals.

Neurosyphilis: Aqueous penicillin G, 18-24 million units a day, as 3-4 million units IV q4h for 10-14 days.

Penicillin allergy in patients with primary, secondary, or early latent syphilis (<1 year of duration): doxycycline 100 mg orally 2 times a day for 2 weeks.

Penicillin allergy in patients with late latent syphilis or latent syphilis of unknown duration: doxycycline 100 mg orally 2 times a day for 4 weeks. (If duration of infection is known to be <1 year, administer for 2 weeks.)

Neurosyphilis: procaine penicillin 2.4 million units IM daily, plus probenecid 500 mg orally 4 times a day, both for 10- 14 days


Diagnosis and Treatment of Viral Sexually Transmissible Infections


Diagnostic Methods

Recommended Treatment Regimens

Herpes simplex virus

Clinical appearance (confirm with culture)

Cell culture

First clinical episode: Acyclovir 400 mg orally 5 times a day for 7-10 days, or famciclovir 250 mg orally 3 times a day for 7-10 days, or valacyclovir 1 g orally 2 times a day for 7-10 days.

Recurrent episodes: acyclovir 400 mg orally 3 times a day for 5 days, or 800 mg orally 2 times a day for 5 days or famciclovir 125 mg orally 2 times a day for 5 days, or valacyclovir 500 mg orally 2 times a day for 5 days

Daily suppressive therapy: acyclovir 400 mg orally 2 times a day, or famciclovir 250 mg orally 2 times a day, or valacyclovir 250 mg orally 2 times a day, 500 mg orally 1 time a day, 1,000 mg orally 1 time a day

Human papilloma


Clinical appearance of condyloma papules


External warts: Patient may apply podofilox 0.5% solution or gel 2 times a day for 3 days, followed by 4 days of no therapy, for a total of up to 4 cycles, or imiquimod 5% cream at bedtime 3 times a week for up to 16 weeks. Treatment area should be washed with mild soap and water 6- 10 hours after application. Provider may administer cryotherapy with liquid nitrogen or cryoprobe, repeat every1-2 weeks; or podophyllin resin 10-25% in compound tincture of benzoin in small amounts to each wart, repeat weekly if necessary; or TCA or bichloracetic acid 80-90% in small amounts to each wart, repeat weekly if necessary; or surgical removal.

Vaginal warts: cryotherapy with liquid nitrogen, or TCA 80-90%, or podophyllin 10-25%

Human immuno

deficiency virus

Enzyme immunoassay

Western blot (for confirmation of enzyme


Polymerase chain reaction

Antiretroviral agents

Centers for Disease Control and Prevention. 1998 Guidelines for the treatment of sexually transmitted diseases. MMWR 1998;47(RR-1)


 Treatment of Pelvic Inflammatory Disease





Cefotetan (Cefotan) 2 g intravenously every 12 hours; or cefoxitin (Mefoxin) 2 g intravenously every 6 hours plus doxycycline 100 mg intravenously or orally every 12 hours.

Ofloxacin (Floxin) 400 mg orally twice a day for 14 days

plus metronidazole 500 mg orally twice a day for 14 days.


Clindamycin 900 mg intravenously every 8 hours plus gentamicin loading dose intravenously or intramuscularly (2 mg/kg of body weight), followed by a maintenance dose (1.5 mg/kg) every 8 hours.

Ceftriaxone (Rocephin) 250 mg intramuscularly once; or cefoxitin 2 g

intramuscularly plus probenecid 1 g orally; or other parenteral third-generation cephalosporin (eg, ceftizoxime, cefotaxime) plus doxycycline 100 mg orally twice a day for 14 days.


II. Chlamydia Trachomatis

A. Chlamydia trachomatis infection is the most prevalent STI in the United States. About 4 million cases occur annually. The incidence of infection is two to three times higher among African-American women compared with white women. Chlamydial infections are most common in women age 15-19 years is recorded.

B. Routine screening of asymptomatic, sexually active adolescent females undergoing pelvic examination is recommended. Annual screening should be done for women age 20-24 years who are either inconsistent users of barrier contraceptives or who acquired a new sex partner or had more than one sexual partner in the past 3 months. Women age 25 years and older who meet both criteria should be screened annually. Women with mucopurulent cervicitis, women undergoing induced abortion, women attending STI clinics, and women in detention facilities also should be screened.

III. Gonorrhea

A. Gonorrhea has an incidence of 800,000 cases annually. Rates of gonorrhea are highest in the southeastern United States and in large cities. Rates are higher among African Americans than among whites or other racial groups.

B. Routine screening for gonorrhea is recommended among women at high risk of infection, including prostitutes, women with a history of repeated episodes of gonorrhea, women under age 25 years with two or more sex partners in the past year, and women with mucopurulent cervicitis. Women with gonorrhea also should be tested for chlamydia and offered testing for HIV infection.

IV. Syphilis

A. Over the past five decades, syphilis has decreased dramatically in the United States, with a current incidence of 100,000 cases annually. The rates are highest in the South, among African Americans, and among those in the 20- to 24-year-old age group.

B. Prostitutes, persons who exchange sex for money or drugs, persons with other STIs, and sexual contacts of persons with active syphilis should be screened.

V. Herpes simplex virus and human papillomavirus

A. An estimated 200,000-500,000 new cases of herpes simplex occur annually in the United States, and 25-31 million individuals are infected with the virus. New infections are most common in adolescents and young adults. Routine screening for genital herpes simplex in asymptomatic patients is not recommended.

B. About 500,000 to 1 million new cases of human papillomavirus infection occur annually, and an estimated 24 million Americans are infected. About 30% of young, sexually active individuals are infected. Routine screening is not indicated.

VI. Human immunodeficiency virus

A. More than 513,000 cases of AIDS have been reported in the United States, and more than 62% of these individuals have died. Women account for 19% of adult and adolescent AIDS cases. Eighty-five percent of cases in adult women are among those aged 15-44 years old. Thirty-eight percent of women were exposed through heterosexual contact.

B. Risk factors for HIV should be assessed in all patients by obtaining a sexual history and information about drug use. Women at high risk of HIV infection should be offered testing. Women at risk for HIV infection include past or present intravenous drug users; those seeking treatment for an STI infection; those exchanging sex for drugs or money or whose sexual partners do; those whose past or present partners were HIV infected, bisexual, or injection drug users; and persons with a history of transfusion between 1978 and 1985.

VII. Pelvic inflammatory disease

A. About 1 million cases of PID occur in the United States annually. Risk factors for PID include young age, low socioeconomic status, unmarried status, residence in an urban area, douching, and smoking. Pelvic inflammatory disease is a polymicrobial infection, but in 65-70% of cases either C trachomatis, N gonorrhoeae, or both are isolated.

B. N gonorrhoeae is usually a symptomatic infection. PID attributable to C trachomatis frequently may be asymptomatic or associated with atypical symptoms such as intermenstrual bleeding or vaginal discharge.

Criteria for Hospitalization of Pelvic Inflammatory Disease

$ The diagnosis is uncertain and surgical emergencies such as appendicitis and ectopic pregnancy cannot be excluded

$ Pelvic abscess is suspected

$ The patient is pregnant

$ The patient is an adolescent (among adolescents, compliance with therapy is unpredictable)

The patient has human immunodeficiency virus infection

$ Severe illness or nausea and vomiting preclude outpatient management

$ The patient is unable to follow or tolerate an outpatient regimen

$ The patient has failed to respond clinically to oral antimicrobial therapy

$ Clinical follow-up within 72 hours of starting antibiotic treatment cannot be arranged.